Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine by N.D.
Nxumalo, T. Field..............................................................................................
This paper reviews mine closure planning at Tshikondeni coal mine, which commenced in 2014. The review presents the mine closure processes as regulated by South Africa’s principal mining legislation, the Mineral and Petroleum Resources Development Act 28 of 2002, and other relevant regulatory frameworks. The results are utilised to acquire a better understanding of mine closure planning with the potential to transition a mining economy into an eco-tourism economy that could preserve livelihoods and generate self-reliant communities.
A novel index for resilience measure of critical infrastructure systems in underground coal mines based on the operating environment: Case-study by R.N.
Masir, M. Ataei, F. Sereshki
This paper aims to evaluate the resilience of the underground coal mining environment using historical data and expert judgment. The study serves as a framework for optimising the utilisation of critical infrastructure to minimise operational disturbances. To achieve this, a practical methodology has been developed. A case study is conducted to demonstrate the real-world applicability of the proposed method, and the resilience index is introduced providing a clear metric for resilience assessment.
Assessing the status quo of artisanal and small-scale mining in South Africa: Opportunities, challenges, and future directions by N. Rembuluwani, L. Diko-Makia
This paper presents an overview of the South African artisanal and small-scale mining sector and its current status quo. The paper identifies ways in which artisanal and small-scale mining can support local development, create employment opportunities, and reduce poverty. The future will largely depend on improved legislation, enhanced personnel capacity, and more sustainable practices to ensure that the positive outcomes of the industry outweigh the negative ones.
Identifying strategic gaps and opportunities in sustainable development initiatives within the South African mining industry by T.C. Maswanganyi, G.L. Smith, R.C.A. Minnitt
In contributing towards the advancement of sustainable development in mining host communities, mining companies will not only fulfil a legal requirement in terms of the Minerals and Petroleum Resources Development Act, but will also prevent negative social and economic impacts in those communities. This paper identifies innovative and cost-effective ways of advancing sustainable development by integrating strategic supply chain management, strategic long-term planning, and sustainability planning.
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1 under varying process conditions by C.N. Eze, N.M. Ugwoju, O. Nnabuife, S.C. Enemuor, V. Okechukwu, C.K. Ezeh
In this study, the efficacy of Providencia vermicola KUBT-1 in the leaching and beneficiation of Agbaja iron ore, a Nigerian low-grade ore containing about 43%–52% iron, was evaluated under varying conditions of temperature, ore particle size, and pH. Correlation analysis of the results with Pearson’s correlation model showed a positive correlation between iron upgrading and sulphur-phosphorus removal (r =1.000, and r =0.967), respectively. These results present Providencia vermicola KUBT-1 as a promising candidate for large scale leaching and beneficiation of Agbaja iron ore.
A review of circular economy opportunities in the mining sector by S. Khan, F. Magweregwede 719
In this paper the challenges of implementing a circular economy in the mining sector are discussed. Circular economy opportunities were identified and categorised according to the three circular economy principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems. The most implementable circular economy opportunities are those aligned with the second principle of keeping materials in use. The high impact opportunities aligned with the first and the third principles are more difficult to implement as they require large investments.
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia by F. Agyemang, J.C.N. Ashukem
This article hypothesises that effectively managed financial provision could be valuable for rehabilitating ownerless legacy mines. Using a qualitative, comparative methodology, the article analyses the financial provisions for mine rehabilitation in South Africa and Western Australia. The article recommends that South Africa adopt a levy-based financial mechanism, strengthen legislative enforcement, improve financial oversight, and integrate proactive mine closure strategies to accelerate rehabilitation, reduce environmental hazards, and promote sustainable development in mining-affected communities.
The blast-induced noise and ground vibration structural and human response: A case for the South African mud house homes by X. Gumede
This paper evaluates the currently adopted safe limit criteria used in South Africa for a mud house. The aim of the study was to measure the magnitude of blast-induced triggers experienced at the aggrieved homestead and to establish if an irritation or damage may be caused by these triggers. Results showed that the seismicity was below the perceptible vibrations obtained from daily home activities. Noise, rather than seismicity, was found to be the more likely cause of damage to the structure assessed. A new approach is proposed based on relating safe limits to structural and human responses.
Journal Comment
Environmental, social, and governance (ESG) considerations have become increasingly important in the business world and contribute to long-term sustainability and responsible corporate behaviour. An ESG-driven strategy is not only a responsible approach to business but also an imperative for long-term success. It can contribute to risk mitigation, enhance reputation, attract capital, foster innovation, and engender social license to operate, making it an enduring competitive advantage. Despite varied acceptance and interpretation, ESG considerations are crucial for addressing environmental and social challenges and ensuring sustainable development of the mineral industry.
The role of the Southern African Institute of Mining and Metallurgy (SAIMM), in the promotion of ESG, is based on the premise that sustainability, and the contribution of the mining and minerals industry to society, is dependent on the professional and ethical conduct of minerals industry professionals – our members.
This journal edition is a wide-ranging collation of environmental, social, and governance sustainability topics intended to broaden perspective on the penetration of ESG sustainability considerations across the minerals industry.
The paper by Nxumalo and Field describes an approach to improve understanding of mine closure planning at Tshikondeni coal mine and identifies closure processes that achieve post-mining land use that aligns with a post-closure strategy to transition from a mining to an eco-tourism economy that can preserve livelihoods and self-reliant communities.
Masir et al. present a framework to optimise the utilisation of critical infrastructure and minimise operational disturbances to coal longwall mining operations, whilst introducing a system resilience index to optimise equipment use and longevity.
The opportunities and challenges associated with the nature of artisanal and small-scale mining are explored by Rembulwani and Dikio-Makia.
Maswanganyi et al. explore gaps and opportunities in sustainable development initiatives within the South African mining industry.
Bioleaching of metals is not new technology, however the paper by Eze et al. highlights the presence and application of indigenous ore-hosted microbes with bioleaching and beneficiation potentials that can be exploited to upgrade an iron ore resource with phosphorus and sulphur content.
Khan and Magweregwede explore circular opportunities in the mining sector and conclude that the most implementable circular economy opportunities are those aligned with the second principle of keeping materials in use. High impact opportunities are aligned with the first principle of designing out waste and pollution, whilst application of the third principle of regenerating natural systems, is more difficult to implement owing to large investment requirements.
A comparative consideration of environmental law in South Africa and Australia by Agyemang and Ashukem results in a conclusion that an approach based on a managed financial provision would be appropriate for effective rehabilitation of legacy mining operations. However, the approaches differ between countries in that South Africa, guided by the Mineral and Petroleum Resources Development Act of 2002, depends on state budget allocations, leading to funding inconsistencies and slow progress. Whilst, in contrast, the Western Australia’s Mine Rehabilitation Fund Act of 2012 relies on a levy-based system, ensuring continuous financial support for mine rehabilitation.
The study by Gumede on blast induced noise and ground vibration on mud house homes identified gaps in current regulatory instruments and established that current safe limit criteria focus on general structural damage with little regard to human impact and response. A new approach is proposed, based on relating limits to the structural and human response.
The diversity of these topics and the associated insights highlight the inherent complexity of effectively dealing with ESG sustainability matters. However, whilst effectively addressing ESG matters involves investment, it will create long-term value for all stakeholders, build resilience, and position mining companies for success in an increasingly sustainability-conscious world.
G.L. Smith
President’s Corner
AThe first one hundred days and beyond
s I write this December President’s Corner, it has been 114 days since my inauguration on 14 August 2025. This is a good moment to reflect on an exceptional period of progress, and what we have achieved, thanks to the dedication of the SAIMM Secretariat, Council, office bearers, and all our committee volunteers.
It has been a time of focused leadership, deep engagement with external partners, and the early steps in shaping a clear and compelling SAIMM value proposition.
Strengthening our foundation
At my inauguration, I committed to strengthening the SAIMM Operating Model and that remains central to everything we are doing. Our aim is simple: to deliver value consistently and reliably to our members, corporate partners, collaborators, universities, and the broader industry.
A strong operating model is the foundation that allows us to honour this responsibility, grow the Institute, and expand our impact in the minerals sector.
Governance in action
A key part of this journey has been to reinforce the role of Council. As the governing board of the SAIMM, Council is responsible for strategic direction and effective oversight. For many newly elected members, this is their first experience serving in a formal governance role and it mirrors the responsibility of company directors. It is a powerful developmental opportunity for individuals and for the industry.
The day after the AGM, we held a comprehensive Council induction, designed to clarify the responsibilities of council members under the constitution and align these roles with the King IV principles. Each council member has committed to fulfilling these duties with care, clarity, and professionalism.
The office bearers form the executive team of the Institute. They are responsible for executing strategy and managing daily operations. This group includes the immediate past president, current president, president-elect, senior and junior vice-presidents, honorary treasurer, finance manager, and general manager.
Building the SAIMM Operating Model
Together with the leadership team, we have developed a functional framework for the operating model, which continues to be refined through ongoing feedback and beyond my presidency. A visual representation is now available and serves as a central reference across the Institute. It connects our constitution, by-laws, and terms of reference and allows every volunteer to quickly find the terms of reference and objectives of every one of our committees through a single point of access.
Every meeting, whether council, office bearers, the 22 committees, or weekly management meetings, now operate with a planned agenda. Each one sets out its purpose, expected outcomes, required results, and the approach to achieving the result. Feedback has been overwhelmingly positive. The change has been immediate, meetings are more focused, and outcomes are being achieved. We now also close each meeting with plus-delta feedback to ensure continuous improvement of every meeting. The days of long meetings without impact are behind us.
We have also begun to use data to support operating model priorities and guide decision-making in the appropriate meetings.
Growing our membership and reach
Our membership data clearly showed the need for deeper student engagement. Together with YPC Chairperson Connie Chijara, I visited several universities and presented to over 500 students. This effort has already led to a 45% increase in student membership over the past 10 weeks.
We have also learned that student chapters need to be re-established at each university to strengthen ongoing engagement. February, with no exams, is ideal for this. In 2026, we will visit Wits, UJ, UP, NWU, UL, and UNIVEN, supported by a SAIMM activation table to assist with registration. This process is now formally embedded into our operating model, with a clear procedure, timeline and accountability. The Young Professionals Council has set a bold target of 1 000 student members by the end of 2026.
President’s Corner (continued)
In parallel, the Membership Committee has set a strategic goal to double overall membership by 2026. This has put a spotlight on the registration process, where many new applicants are delayed by missing documents or proposer/seconder issues. The Head of Membership is streamlining the process and addressing gaps in our membership software with the vendor.
Journal, events, marketing and professional registration
The SAIMM Journal continues to be a respected, international publication. It is led by a professional and committed committee. However, a significant backlog of papers has emerged, driven by a manual and inconsistent review process. This is now being fully mapped to identify and resolve the bottlenecks.
Standard operating procedures are also being developed across all functions, from membership to events and finance, to ensure consistency and reliability in how we deliver. This is being supported by a digital strategy and roadmap, which will integrate membership, event, and financial data to enable more targeted event marketing and member engagement.
On the communications side, we have sharpened our content and improved visibility. Our LinkedIn following grew by 6 000 this year, and Facebook by 500. This reflects stronger outreach, better messaging and a renewed energy around the SAIMM brand.
We are also aligning our efforts with the new ECSA Identification of Engineering Work (IDoEW) requirements. The SAIMM is well positioned to support engineers through this transition, from structured mentoring across the 11 defined competencies, to professional registration support and continuing professional development (CPD). As a recognised voluntary association, our technical programme and membership contribute directly to the 25 CPD points required over a five-year cycle.
Industry engagement and conferences
I have had the privilege of engaging with many stakeholders this quarter, giving presidential openings and addresses at events including AfriRock 2025, the 13th International Heavy Minerals Conference, the International Mineral Asset Valuation Conference, the Geometallurgy Conference, the Student Colloquium, the 9th International PGM Conference, AI for Leaders, 2025 Mine Safe and Industry Awards Day, and the SAIMM Limpopo Branch Technical Conference.
It has been encouraging to see increased attendance at all these events. The PGM Conference, which I have been attending for the past 16 years, reached its highest-ever turnout, with over 300 delegates. These events are a vital part of the SAIMM’s value proposition and continue to play a central role in knowledge sharing and professional growth.
Meeting young engineers at the Limpopo Branch Conference, professionals who work underground every day, left me feeling inspired and confident in the future of our industry. Their commitment, optimism and drive were truly energising.
A word of thanks
A heartfelt thank you to our corporate partners, Ukwazi, Valterra Platinum, Sibanye Stillwater, SRK Consulting, Impala Platinum, and Sound Mining Solutions, for their continued support of the SAIMM.
Although I have served the SAIMM for more than 20 years across committees and Council, I never fully appreciated the full extent of the Institute’s activities. The Secretariat, a team of 18 full-time employees, and 4 interns, go above and beyond, often working weekends to support university events. And our Council, office bearers and 22 committees are made up of more than 200 committed volunteers who also occupy full-time roles across the mining sector.
A special mention to our branch chairpersons and their respective committees that are ensuring we reach all our members and stakeholders across Zambia, Zimbabwe, Namibia, Botswana, Limpopo, Zululand, Western Cape, North West, Northern Cape, Johannesburg, and Pretoria.
To all of you and to every member of the SAIMM community, thank you for your support over the past 114 days. I am excited about what we will accomplish together in 2026.
Wishing you a peaceful festive season. Please travel safely and return refreshed for the year ahead.
Warm regards
G.R. Lane President, SAIMM
Affiliation:
1University of the Witwatersrand, South Africa.
Correspondence to:
N.D. Nxumalo
Email:
9606378a@students.wits.ac.za
Dates:
Received: 17 Jun. 2022
Revised: 24 Oct. 2022
Accepted: 22 Aug. 2025
Published: December 2025
How to cite:
Nxumalo, N.D. Field, T. 2025. Review of mine closure planning, processes, and post-closure strategy at Tshikondeni coal mine. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 675–682
DOI ID: https://doi.org/10.17159/2411-9717/2175/2025
ORCiD:
N.D. Nxumalo http://orcid.org/0009-0007-3959-1695
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
by N.D. Nxumalo1, T. Field1
Abstract
Since the discovery of gold on the Witwatersrand in 1886, mining has been at the centre of South Africa’s development. Although mining continues to contribute significantly to the country’s economy, it is a temporary land-use activity, and mine closure is inevitable. This paper reviews mine closure planning at Tshikondeni coal mine, which commenced in 2014 with the initiation of mine closure. The review presents the mine closure processes undertaken at the Tshikondeni coal mine as regulated by South Africa’s principal mining legislation, the Mineral and Petroleum Resources Development Act 28 of 2002, and other relevant regulatory frameworks. To compile this review: (1) A desktop study was conducted; (2) empirical data was collected through one-on-one interviews with research participants at Tshikondeni coal mine; and 3) physical observations were made of the rehabilitation at various mine operations within the Tshikondeni coal mine complex. Research participants consisted of mine officials from different departments, i.e., human resources, and environmental, social, and business strategy, who were directly involved with the Tshikondeni coal mine closure. A questionnaire with semi-structured questions was developed. It was utilised to acquire a better understanding of mine closure planning at Tshikondeni coal mine and identify mine closure processes that aim to achieve post-mining land uses and align with Tshikondeni coal mine’s post-closure strategy, namely the Tshikondeni Legacy Project, with a post-closure strategy that has the potential to transition a mining economy to an eco-tourism economy that can preserve livelihoods and selfreliant communities.
Mineral resources are finite. When they are exploited through mining activities, the mine will eventually reach the end of its life or a level at which mining is no longer economically viable. At that stage, mine closure is inevitable, and mine operators need to initiate a mine closure process. The concept of mine closure dates to the nineteenth century. It has since developed differently across mining jurisdictions and is driven primarily by environmental impacts (Field, 2019). As the concept of mine closure progressed, it shifted from the core idea of reclamation towards remediation and mine closure has become a critical phase in the life cycle of mining operations (Field, 2019). Historically, mining has left a legacy that affects natural and social aspects negatively. Therefore, future mining activities, rightly or wrongly, will be judged against the legacies of past and current poor performers (Worrall et al., 2009). Unplanned or poorly planned mine closures often lead to environmental liability associated with unrehabilitated mine sites (Cowan et al., 2010). The success of mine closure relies primarily on planning with a clear understanding of the key closure hazards and associated risks for the mining site (McCullough, 2016) and, additionally, on well-defined mine closure processes and the allocation of financial resources (Butler, Bentel, 2011).
To undertake proper mine closure planning, several national and international industry guides have been developed (Butler, Bentel, 2011). These planning frameworks and guidelines began to develop in the early 2000s as sufficient attention to mine remediation/rehabilitation started to be recognised increasingly as a key aspect of sustainability in the mining industry (Cowan et al., 2010).
In general, major mining jurisdictions regulate mine closure primarily under their principal mining and environmental legislation, as is the case in South Africa. The first introduction of mine closure in
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
South Africa, particularly in mining legislation, was in the Minerals Act 50 of 1991 for surface rehabilitation. As mining legislation evolved, the provisions for mine closure have expanded and extended beyond the construct of surface rehabilitation.
Tshikondeni coal mine (TCM) is a South African mine owned by Exxaro Resources Ltd. TCM presents one of the recent cases of mine closure. A review of the TCM mine closure aims to provide insight into the approach undertaken through mine closure planning and mine closure processes towards a sustainable postclosure economy that can support self-reliant mining communities.
Tshikondeni coal mine
TCM is situated in the northern region of the Limpopo Province within the Vhembe District Municipality and the Mutale Local Municipality, and it is adjacent to the northern boundary of the Kruger National Park (KNP), as indicated in Figure 1 (TCM Social and Labour Plan, 2018). TCM is a metallurgical coal mine owned by Exxaro Resources, which is also the mining right holder.
The mine has a lease area of 22,027 ha, made up of two portions namely the eastern portion and the western portion (Exxaro Mineral Resources and Ore Reserves Report, 2014). The western portion is where the majority of TCM activities are located, and it is approximately 16,500 ha. TCM started operating in 1984 as an underground coal mine using the bord and pillar mining method. The mine comprised six shafts, namely Nyala, Eland, Duiker, Nari, Mopani, and Kremetart (Exxaro Mineral Resources and Ore Reserves Report, 2014).
The mine further had three opencast mini pits that were mined from 2011 to 2014. Since its inception in 1984, TCM mined up to 580 kilotonnes per annum of premium metallurgical coal, which was supplied solely to ArcelorMittal for steel production. TCM’s mineable coal reserves have since been depleted and the mine has been undergoing closure since 2015 (Exxaro Mineral Resources and Ore Reserves Report, 2014). Hence, Exxaro Resources has developed a post-closure economic strategy to transform the area from mining to ecotourism by taking advantage of the proximity of the mine to both the Makuya Nature Reserve and KNP.
Background – Makuya Nature Reserve
Makuya Nature Reserve is part of the Vhembe Biosphere Reserve. It is internationally renowned for its wildlife, cultural diversity, and unique biological resources. Makuya shares a fenceless border with the Kruger National Park (KNP), which is within the Greater Limpopo Transfrontier Conservation Area (GLTFCA), bordering Pafuri, as represented in Figure 1 (Vhembe District Municipality IDP Review, 2019/2020). The nature reserve is managed in terms of a co-management agreement between the Limpopo Department of Economic Development, Environment and Tourism (LEDET) and the Makuya Tribal Council.
Makuya Nature Reserve is strategically positioned within the GLTFCA, which is a socio-economic development node for two activities, namely conservation and tourism. Before it being declared a nature reserve, the land was used for grazing, hunting, and collecting thatching grass and medicinal plants (Webster, 2007). Currently, three tribal communities derive some economic value from the land through hunting activities and the LEDET, which pays the community conservation levies for the land. LEDET pays an annual conservation levy of R12/ha and the hunting activities at Makuya Nature Reserve generate an annual income more than R2 million (DEFF, 2003). The funds generated from both the hunting activities and the conservation levy are intended for the benefit of community development as well as conservation activities. The conservation levy is transferred to the tribal authorities for the development and benefit of the communities.
Methodology
Mine closure planning is implemented by undertaking several processes that include closure planning, stakeholder engagement (community and employees), progressive rehabilitation, financial provisioning, compliance and monitoring, and relinquishment. This review was performed in three steps: 1) A desktop study was conducted; 2) empirical data was collected through one-on-one interviews with research participants at Tshikondeni coal mine; and 3) physical observations were made of the rehabilitation at
Figure 1—Tshikondeni coal mine location and lease boundary (TCM Social and Labour Plan, 2018)
Review of mine closure planning,
processes, and a
various mine operations within the Tshikondeni coal mine complex. Research participants consisted of mine officials across different departments (i.e., human resources, environmental, social, and business strategy) who were directly involved with the Tshikondeni coal mine closure. A questionnaire with semi-structured questions was developed. It was utilised to acquire a better understanding of mine closure planning at Tshikondeni coal mine.
Furthermore, the findings from the interviews and observations at the TCM site are juxtaposed to the mine closure provisions in South Africa’s mining legislation. These provisions are in the principal mining legislation, the Minerals and Petroleum Resources Development Act 28 of 2002 (MPRDA), the National Environmental Management Act 107 1998 (NEMA), and National Water Act 36 of 1998 (NWA) that have provisions for environmental management, including rehabilitation and mine water management, respectively, as well as financial provisioning for rehabilitation, decommissioning, and closure activities in the Financial Provisions Regulations 2015 under the NEMA and the recently gazetted draft National Mine Closure Strategy (NMCS) under the MPRDA. According to the strategy, regional mine closure plans are intended to align the individual mines’ closure plans that are situated close to one another. Thus, regional mine closure plans aim to ‘‘prevent or minimise adverse long-term environmental and socioeconomic impacts and create a self-sustaining natural ecosystem or alternative land use’’ (Draft NMCS, 2021). This will also encourage collaboration among mining companies in mine closure planning and develop sizeable alternative economies that will sustain mining communities post-closure. In addition to the legislation above are provisions for addressing downscaling and retrenchments for any company with employees, as per the Labour Relations Act (LRA) 66 of 1995.
Findings and observations
Mine closure planning at TCM
Mine closure planning for TCM began approximately three years before the actual closure commenced. When initiating the mine closure process, the mining right holder generally undertakes several activities that include addressing the legal obligations, developing the mine closure plan, collecting data for analysis, and engaging with relevant internal and external stakeholders.
Initiating mine closure at TCM
TCM began downscaling its operations in 2011 in preparation for mine closure, which was planned to commence in 2014/2015. Thereafter, the mine initiated section 189(1) of the LRA process as per the prescripts of the law when an employer intends to institute retrenchments. TCM eventually ceased to operate in late 2014 when the viable coal resources had been exhausted. In December 2016, the mining right holder submitted TCM’s environmental management plan for closure to the then Department of Mineral Resources. The environmental management plan was approved in December 2017. Additionally, as required by law, each mine operation with a mining right has the legal obligation to implement social labour plans (SLP) for the mining communities as per regulation 41 of the Amended Mineral and Petroleum Resources Development Act 28 of 2002 (MPRDA). An SLP allows the mining right holder to contribute positively to the long-term sustainability of its communities through social and economic projects. As part of the social strategy toward mine closure, TCM conducted a situational analysis of the surrounding communities of Mukomawabani, Mutele B and Sanari. Independent consultants
post-closure strategy at Tshikondeni coal mine
were appointed to undertake the study in 2017. The findings were used as input into the SLP. A top critical need observed amongst the three surrounding villages was access to water. Consequently, findings from the situational analysis report were implemented as social infrastructure projects that included three crèches (one in each village), a community hall in Mukomawabani Village, and 56 houses (twenty houses in Mukomawabani Village and eighteen houses in both Sanari and Mutele B villages, respectively).
Developing a mine closure plan
TCM’s mine closure plan was developed by independent consultants who took guidance from the relevant regulatory frameworks to comply with the mine closure requirements of various regulatory bodies. This reiterates findings from a survey by Milaras et al. (2014) indicating that mining companies often outsource mine closure plan development to independent consultants instead of using in-house personnel.
Stakeholder (community and employees) engagement
The stakeholders most affected by mine closure are the employees and communities. Employees are at risk of losing employment, and communities that have secured economic opportunities with the mine as a supplier or service provider are at risk of losing employment, and also lose benefits from social projects initiated by the mine under the SLP. Thus, when TCM initiated mine closure, stakeholders, including employees and communities, were engaged.
Community engagement
During mine closure planning, communities can be engaged using an SLP as an instrument that registers their expectations for post-mining land uses, aiming to achieve self-reliance. However, the key to value creation and self-reliance in mining communities is their ability to be organised. The Royal Bafokeng Nation (RBN), although not a traditional community where Tshikondeni coal mine is located, presents a great model of the importance of organised mine communities with clear balanced governance structures. RBN is a native Setswana-speaking community of approximately 150,000 people who live on their ancestral land of 1,400 km² near Rustenburg, in the North-West Province, South Africa.
The fundamental building blocks on which the RBN's governance structure is built are kgosi (king), morafe (nation/ community) and land. The structure does not apportion any hierarchical status between kgosi and morafe but realises that kgosi ke kgosi ka morafe. This means the community maketh the king; therefore, without the community, there can never be a king. RBN engagements with external stakeholders are built precisely on this principle and communal decisions are made through their threelegged governance structure, as presented in Figure 2, during internal engagements.
According to Ostrom (2000), ‘‘in self-organised regimes the rules have to be clear to all participants and the members need to know with whom to cooperate’’. Furthermore, a research study conducted by Medvey (2010) at Makuya Nature Reserve about surrounding communities found that communities are often faced with the challenge of striking the right balance between their traditional practices and democratic institutions. Although, traditional communities such as the Makuya have a form of communication structure through their tribal authority, communities have expressed their dissatisfaction with tribal authorities who made decisions on their behalf without in-depth engagement (Medvey, 2010).
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
Hence, based on Ostrom’s (2000) self-organised regimes and Medvey’s (2010) findings, the Makuya traditional community, as one of the surrounding communities of the Makuya Nature Reserve, may be perceived and categorised as not being a self-organised traditional community. This may pose a risk to the success of Tshikondeni Legacy Project (TLP) to deliver a sustainable postclosure economy after relinquishment. Makuya Nature Reserve is co-managed by LEDET and the Makuya traditional community, thus the institutional arrangement between the two parties needs to be solid for a successful post-closure economy. Proper management structures and commitment are critical for driving TLP postclosure, otherwise, an alternative economy envisioned to deliver a sustainable future is at risk to fail. Whilst organised communities are a key factor to the success of projects, it is also critical for communities to take ownership of projects.
The Makuya community has adopted the motto of “Nothing on our land about us for us without us”; therefore, the community expects their needs and their presented projects to be considered during mine closure planning without feeling that certain projects are imposed on them (Mazibila, 2015).
SLP projects, particularly those developed to support communities’ livelihoods post-mine closure, need to be inclusive and consider communities’ inputs. Communities often suggest developmental projects that address their immediate social needs. If those needs are considered, it may be easier for communities to commit and take ownership of the economic projects that are implemented by mining companies (Medvey, 2010). Therefore, continuous engagements with communities to empower them may lead to communities accepting these economic projects. In turn, this may lead to communities taking ownership of these projects after relinquishment and becoming self-reliant
Employee engagement
The employee engagement as per section 189 is presented in the closure planning, and the section 189 profit-to-revenue ratio of the relevant mine to be less than 6 per cent on average for an agreement was signed to protect the people. Section 52(1) of the MPRDA requires the holder of a mining right to notify the Minister of Mineral Resources in the prescribed manner where prevailing economic conditions cause the continuous period of twelve months. Additionally, if any mining operation is to be scaled down or cease with the possible effect that 10 per cent or more of the labour force or more than 500 employees, whichever is the lesser, are likely to be retrenched in any twelve months, the holder of the mining right remains responsible for managing the retrenchment processes because of its obligations in terms of section 52 of the MPRDA.
At TCM, the process of equipping employees in low-skilled positions with portable skills to pursue alternative employment and participation in meaningful economic activity has been ongoing during the mine closure phase. The portable skills provided include training in poultry farming, tiling, and plumbing. TLP, as a postclosure strategy, also includes skills development aligned with SLP initiatives that will provide communities with training and skills that will serve the biodiversity, economy, and conservation of the area.
Progressive rehabilitation
At the TCM site, rehabilitation of areas that were once opencast pits and openings was observed. The pits were filled with soil and left to be revegetated naturally with native vegetation that aligns with its post-mining land uses. Thus, rehabilitated areas that were covered with soil were left to revegetate naturally with grass and mopane trees, as can be observed in Figures 3 and 4. Although quantifying
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
the amount of rehabilitation conducted at TCM is beyond the scope of this study, observations of the physical rehabilitation confirm that progressive rehabilitation was conducted to return the land to its original state before mining. The rehabilitation of box cuts and mini pits began in 2016. During a site visit in November 2018, the holes were filled and covered with topsoil. A desktop study on land rehabilitation revealed that 198 ha of land was disturbed because of mining activities at TCM. By the end of Exxaro’s 2020 financial year 139 ha of land had been rehabilitated.
Figure 5 illustrates the previous TCM coal-processing plant infrastructure at the mine complex. All the coal-processing plant infrastructure was decommissioned and dismantled to make way for land rehabilitation as per mine closure provisions in the MPRDA and its regulations. The area was rehabilitated completely and covered with topsoil, returning the land to the wilderness that it was prior to mining activities, as indicated in Figure 6.
Financial provisions
The desktop study indicated that the financial provisioning at TCM was calculated as per the Financial Provision Regulations 2015. The results were first published in December 2015 and amended in September 2018 to align with the new financial regulations. According to Exxaro’s Environmental, Social and Governance (ESG) Report of 2021, all business units within Exxaro review their financial provisions for mine closure and rehabilitation on an annual basis. At this point, amendments to rehabilitation
plans and closure objectives are in line with the environmental management plan. Quarterly, the mining company makes financial contributions to the trust based on closure cost estimates for the remaining life of the mine (Exxaro Resources, 2021). Exxaro has established a groupwise rehabilitation fund, rehabilitation and other environmental liabilities, an environmental rehabilitation fund, and a coal central trust fund. In addition to these financial vehicles, an amount of R4,242 million is provided as a bank guarantee to cover shortfalls in financial provisions and any other environmental liabilities that may arise (Exxaro Resources, 2020). Table 1 presents the mine closure financial provisioning for TCM as extracted from Exxaro’s ESG report of 2020 (Exxaro Resources, 2020).
An accurate calculation of the total amount anticipated for financial provision is critical and a prerequisite for achieving mine closure objectives, including rehabilitation. The survey of Milaras et al. (2014) on mine closure planning found that mine closure planning is usually conducted poorly and that inadequate funds are allocated towards the process. A survey conducted (Intellidex, 2018) to assess the financial provisions of several South African mining companies found that the disclosure by mining companies regarding rehabilitation and mine closure does not provide adequate, meaningful, and comparative information. The sufficiency of financial provision allocated by companies cannot be confirmed based on the information disclosed in their annual integrated reports.
Therefore, Intellidex’s survey could not conclude definitively on the sufficiency of financial provisioning. The information disclosed by mining companies, as also noted in TCM’s mine closure, included: (1) The financial instruments used to provide for future rehabilitation obligations; (2) estimated amounts for
Figure 3—Photograph of rehabilitated Mutale box cut at the TCM complex
Figure 4—Photograph of rehabilitated mini pit 3 with cattle grazing at the TCM complex
Figure 5—Tshikondeni coal-processing plant during its life of mine (Cornish, 2012)
Figure 6—Rehabilitated land where the coal-processing plant had been situated
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
environmental rehabilitation and mine closure obligations, and funds and guarantees available to meet those obligations (Table 1); and (3) responsible individual/entity for estimating the quantum of the environmental rehabilitation and mine closure obligations.
Compliance and monitoring
The legislation and regulatory framework set provisions for mine closure planning. Furthermore, it provides compliance parameters for processes undertaken during mine closure, such as stakeholder engagement, rehabilitation, and financial provisioning. Compliance with these processes is regulated in the MPRDA, NEMA, EIA, and Financial Provisions Regulations. Firstly, a mining right holder needs to submit a mine closure plan to the Department of Mineral Resources and Energy as per section 43 of the MPRDA. NEMA section 24 and EIA Regulations 2017 present provisions for rehabilitation compliance. The desktop study found that the progressive rehabilitation undertaken at TCM was conducted in terms of the current legislation and regulatory framework and is continuously monitored to comply with the desired/planned final land use. The allocation of financial provision for closure was also compiled as per the Financial Provisions Regulations of 2015 (Exxaro ESG Report, 2022).
Relinquishment and monitoring
When TCM reaches its final stage, the Makuya Tshikondeni Development Fund intends to relinquish the mine site gradually to the final land user, namely the Makuya Tribal Council, through the TLP. To mitigate against the failure of the project, TCM intends to relinquish and transfer the TLP progressively to the final land user, to deliver an alternative economy. The following section discusses the economic activities proposed in the TLP that leverage the infrastructure that was invested during the life of Tshikondeni coal mine.
Post-closure strategy
Tshikondeni Legacy Project (TLP) is a mine closure strategy developed by Exxaro Resources. The project is administered under a section 21 company, named Makuya Tshikondeni Development Fund, which comprises representations from Exxaro, the Makuya Tribal Council, and ArcelorMittal. The project is funded by a partnership between Exxaro and ArcelorMittal to the value of R16 million. The project is part of the Post-mining Investment Programme within the Limpopo Province, valued at R228 million. TLP is positioned as a post-closure alternative economy strategy that is implemented in partnership with relevant stakeholders.
Tshikondeni Legacy Project
Tshikondeni Legacy Project (TLP) proposes ecotourism as an
economic activity to replace mining. The project further intends to address the socio-economic aspects of the surrounding communities to preserve their livelihoods post-closure. The economic and developmental initiatives planned in the TLP are intended to deliver sustainable post-closure livelihoods based on integrated final land use. Post-closure economic activities to be delivered through the TLP are based on mined land that, although it has been rehabilitated to its original use, is better resourced to transition to an alternative economy. Over the duration of the life of mine, mining companies invest in varying infrastructure, some of which will be optimised for the post-closure economy. During mine closure at TCM, some of the invested infrastructures were demolished (Figure 7 and Figure 8), whilst another infrastructure was included to fulfil post-closure outcomes (Figure 9 and Figure 10).
Therefore, the combination of infrastructure and the Makuya Nature Reserve present a viable opportunity for the surrounding communities to derive sustainable value that can preserve their livelihood. Throughout the life of mine (LoM), TCM further invested in developmental projects such as photovoltaic solar panels (Figure 9) and water reticulation (Figure 10).
Figure 7—Prefabricated housing at Tshikondeni mine village
Figure 8—Demolished prefabricated house at Tshikondeni mine village
Table 1 Financial provisioning for TCM closure 2019-2021
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
When TCM was still operational, photovoltaic solar panels were erected to supply renewable energy for mining operations and household use at the mine employees’ village. The water project was a joint venture between the Mutale Local Municipality and Exxaro TCM as an SLP initiative to supply four surrounding communities with portable water.
These two projects fulfil the developmental needs of the communities by supplying basic services, electricity, and water. They are also drivers of the economic activities planned in the TLP to establish an alternative economy.
Alternative economy
Findings from the one-on-one interviews with research participants highlight the importance and need to educate communities on the feasibility and viability of SLP projects, particularly those intended to be sustainable post-mine closure. To preserve livelihoods, communities must be engaged in the objectives of SLP projects and their role in economic contribution. The TLP is TCM’s closure strategy and incorporates some of the SLP projects with the potential of being sustainable beyond closure.
The SLP projects that were implemented at TCM before initiating mine closure include Musunda Citrus Farm, Makuya Cattle Lot and Sanari Skills Development Centre. These projects have been identified to survive post-closure, but to be sustainable, the communities must be committed to managing the projects to preserve their non-mining livelihoods. However, the Makuya community claims that these projects have been imposed on them (Medvey, 2010). The community voiced their dissatisfaction about TCM not considering their projects, which include classrooms and a science laboratory at Makuya Secondary School, as SLP initiatives. This highlights a critical point of misalignment between the mining company’s plan and the community’s expectations and desires.
By including communities in project development engagements and during mine closure planning, mining companies can address the communities’ dissatisfaction. This will allow mining companies to incorporate the communities’ developmental needs as best as possible into economic projects that are planned to support a postclosure future and mitigate against the risk of an ‘artificial economy’.
An example of such an artificial economy is a De Beers-owned diamond mine in the Northern Cape. Kleinzee, once a thriving diamond-mining town owned by De Beers, underwent mine closure in 2010. During mine closure, De Beers invested approximately R90 million towards post-closure socio-economic projects in Kleinzee and another neighbouring town, Koingnaas. De Beers invested significant financial resources as part of their post-closure strategy to preserve the livelihoods of the people of Kleinzee and those previously employed at the mine, ensuring that they would not become financial burdens to their respective local municipalities. Several projects, such as an enterprise development hub, a wind farm to generate clean energy, and a small-scale abalone farm, were proposed as alternative economy projects. Mine infrastructure was repurposed for some closure projects, and pumps were converted to reticulate seawater for an oyster farming enterprise. The alternative economy projects were envisioned to create a total of 5 000 jobs and contribute to the local economy as per the De Beers mine closure plan. In 2012, De Beers transferred the town of Kleinzee to the local municipality and proclaimed it a public town. However, alternative economy projects under the local municipality failed to reach planned targets in terms of employment and a sustained post-closure economy, which resulted in some community members leaving town in search of employment elsewhere. The collapse and failure of this post-closure alternative economy could be attributed to the insufficient time frame allocated between the implementation of the projects for the alternative economy and the relinquishment and misalignment of proposed post-closure economic activities.
Furthermore, whilst communities’ developmental needs are urgent and immediate, economic projects suggested by mining companies are geared to drive an alternative economy post-closure and sustain communities’ livelihoods. To transition to an alternative non-mining economy, the TLP proposes projects that will transform Tshikondeni from a mining economy to an ecotourism economy. Ecotourism, as the proposed alternative post-closure economy, intends to deliver a dual purpose: biodiversity and economy conservation.
Proposed projects under the TLP align with the government’s National Biodiversity Economy Strategy (NBES) as documented in the integrated development plans for the Vhembe District. NBES has identified and demarcated the Tshikondeni Biodiversity Economy Node within the Makuya Nature Reserve. The economic activities will be supported through a partnership between government departments (Department of Forestry, Fisheries and Environment, SANParks, LEDET, and the Department of Rural Development and Land Reform) and the Peace Parks Foundation, a non-governmental organisation.
Wildlife hunting, including trophy hunting, is an old-fashioned activity still being practised by the Makuya traditional community. This is one of the significant drivers of the biodiversity economy within the Tshikondeni Biodiversity Economy Node. Associated industries such as taxidermy and the sale of game meat are also planned as economic activities that will support ecotourism. The NBES strategy as documented in the IDPs for the Vhembe District, identifies the sale of live game at auctions as a potentially lucrative business where the price paid for any animal ranges between
Figure 9—Photovoltaic solar panels (1,037 kWp) at TCM
Figure 10—Joint venture water reticulation project
Review of mine closure planning, processes, and a post-closure strategy at Tshikondeni coal mine
R10,000 and R800,000, with an average price of R225,224 per animal. This unlocks economic opportunities for the sale of game meat, animal skin for leather, bones, and horns. Furthermore, including local entrepreneurs in ecotourism presents opportunities to create employment for the Makuya communities who will ultimately become self-sufficient.
Conclusion
The TCM, in undertaking mine closure, has considered and complied with the legal obligations presented in various South African legislative frameworks. As indicated in the aforementioned, TCM initiated mine closure 5 to 10 years before the end of LoM, which is regarded to be too close to the end of LoM in terms of mine closure planning frameworks (ICMM, Integrated Mine Closure: Good Practice Guide, 2019). The TLP proposes sustainable land-use initiatives with the potential to transition a mining economy to an alternative post-closure economy that will deliver self-reliant communities.
According to Kretschmann (2018), an effective postmining strategy like the TLP can potentially provide several opportunities to reinvent previous mine operations and create new jobs. The successful control and management of post-mining risks are fundamental to the effective use of these opportunities (Kretschmann 2018), and failing to do so may create an ‘artificial post-closure economy’ that ultimately yields undesirable results, as seen in the case of the Kleinzee mine closure.
An economy that can replace a mining economy is not only critical but also a necessity for the survival of mining communities that have depended on the mining economy for their livelihoods. An effective progressive rehabilitation for proposed land use choices is a prerequisite to transitioning a mining economy to an alternative post-closure economy. Therefore, during mine closure planning, the proposed final land uses must drive the type of progressive rehabilitation that supports post-mining land uses, enabling a sustainable post-closure economy. TCM also needs to allow the communities and final land users to propose and present their desired economic projects for an alternative post-closure economy. The TCM rehabilitation is on a path to delivering the expected land uses that will carry the proposed economic closure projects for an alternative economy of ecotourism. However, to realise a sustainable post-closure economy, TCM must consider affording sufficient time to initiatives in the TLP to progress from the project phase and to become self-funding from income generated from the proposed ecotourism activities. This is to shift their dependency on the funding from the mine operator to avoid creating an artificial economy that cannot sustain itself post-closure.
Thus, the relinquishment criteria for the TCM must be registered in the TLP to mitigate against the risks that often result from premature and abrupt withdrawal of project funding. Abrupt withdrawal from projects may lead to project failure; ultimately resulting in an unsustainable post-closure alternative economy (Gardiner et al, 2015). In conclusion, planning mine closure closer to final relinquishment fails to recognise that closure planning is a process and not an event. Implementing alternative economy projects closer to relinquishment may lead to an artificial economy and, ultimately, the failure of the post-closure economy.
References
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Intellidex. 2018. Financial provisioning for rehabilitation and mine closure: a study of South African platinum and coal mining companies. Johannesburg, South Africa.
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Milaras, M., Ahmed, F., McKay, T.J.M. 2014. Mine closure in South Africa: a survey of current professional thinking and practice. Weiersbye, I.M., AB Fourie, A.B., Tibbett, M., and Mercer, K. (eds.). Proceedings of the Eighth International Conference on Mine Closure, Cornwall, England. pp. 1–13.
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Webster, W. 2007. Trans-Boundary Natural Resources Management in Southern Africa: Local Historical and Livelihood Realities within the Great Limpopo Trans-Frontier Conservation Area. Worrall, R., Neil, D., Brereton, D., Mulligan, D. 2009. Towards a sustainability criteria and indicators framework for legacy mine land. Journal of Cleaner Production, vol. 17, no. 16, pp. 1426–1434. u
Affiliation:
1Faculty of Mining Engineering, Petroleum and Geophysics, Shahrood University of Technology, Shahrood, Iran
Correspondence to:
R.N. Masir
Email: Raziyh_Norouzi@yahoo.com
Dates:
Received: 16 Oct. 2022
Revised: 16 Feb. 2025
Accepted: 14 Aug. 2025
Published: December 2025
How to cite:
Masir, R.N., Ataei, M., Seresjki, F. 2025. A novel index for resilience measure of critical infrastructure systems in underground coal mines based on the operating environment: Case-study. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 683–694
DOI ID: https://doi.org/10.17159/2411-9717/2396/2025
A novel index for resilience measure of critical infrastructure systems in underground coal mines based on the operating environment: Case-study
by R.N. Masir1, M. Ataei1, F. Sereshki1
Abstract
Given the inherent risks and disruptions in underground coal mining operations, strengthening the resilience of critical infrastructure has become a vital priority. This paper aims to evaluate the resilience of the underground coal mining environment using historical data and expert judgment. The study serves as a framework for optimising the utilisation of critical infrastructure to minimise operational disturbances. To achieve this, a practical methodology has been developed, incorporating nearly two and a half years of collected operational data, a hierarchical structure, and a systematic approach. Furthermore, a case study is conducted to demonstrate the real-world applicability of the proposed method. Finally, the resilience index is introduced as a straightforward summation of ranked impact factors, providing a clear metric for resilience assessment.
The mining industry plays a crucial role in the global economy, holding a significant share in international trade (Da Silva et al., 2021). Mining and its associated industries contribute positively to economic and social development by generating employment and wealth (Brücker, Preuße, 2020; Cruz et al., 2021). Among mineral resources, energy supply sources hold a particularly prominent position, as no industry can sustain itself without a reliable energy supply (Tu et al., 2021; Norouzi Masir et al., 2021). Given coal’s essential role in producing steel, cement, lime, aluminum, and other industrial materials, energy remains a key driver of industrial growth (Kurama et al., 2009; Wu et al., 2012). However, coal mining systems are highly vulnerable to various threats and disruptions that directly impact production capacity (Masir, 2021). These disturbances often stem from system failures (Madni, Jackson, 2009), posing risks to employee safety, health, and security while causing substantial annual economic losses (Hossain et al., 2019). For decades, ensuring the stability and reliability of coal mines has been a fundamental priority in the development of mining infrastructure (Lim-Camacho et al., 2021).
For years, researchers have extensively studied resilience across various engineering industries. However, these studies have notable limitations. Most existing research has primarily focused on energy systems (Hossain et al., 2019; Sabouhi et al., 2019; Zeng et al., 2021), transportation networks (Cerè et al., 2019; Li et al., 2020), and water supply networks (Behzadian et al., 2014), along with quantitative analyses in mining and coal. Despite this, coal mining operations are inherently vulnerable to numerous disruptions, which remain insufficiently explored in the literature. Furthermore, most existing studies primarily present conceptual frameworks and evaluation approaches rather than practical applications. Likewise, methodologically, current resilience measurement approaches often lack sufficient data and fail to account for the work environment. Overlooking operational conditions in resilience analyses can significantly distort results, as environmental factors not only influence system behaviour but also disrupt decision-making processes.
Moreover, effective management decisions from a production perspective require a comprehensive understanding of the interplay between operational capacity, system behaviour, and environmental conditions. Another critical aspect often neglected in resilience calculations is the impact of key influencing factors, such as commitment, sense of ownership, monitoring and prediction, lessons learned, scheduling status, and employment conditions.
A novel index for resilience measure of critical infrastructure systems in underground coal mines
To address these gaps, this paper calculates resilience by integrating environmental failure data and identifying key influencing factors. Specifically, the study assesses critical infrastructure resilience through a three-step process. Firstly, operational environment data is collected. Secondly, the key resilience factors of critical infrastructure and their hierarchical relationships are systematically identified using a multi-criteria decision-making (MCDM) approach, providing a theoretical foundation for understanding resilience impacts. Thirdly, a new resilience indicator for critical infrastructure is introduced, offering a structured framework for resilience assessment.
Literature review
Resilience, derived from the Latin ‘resilire’ (to bounce back), initially emerged in ecosystem studies and has since expanded into multiple disciplines (Hossain et al., 2019). It is generally categorised into four approaches: empirical, conceptual framework, simulation, and index-based methods (Rød, 2020). Empirical models analyse resilience quantitatively using failure behaviour and recovery curves, subdivided into deterministic and probabilistic frameworks (Bruneau et al., 2003; Youn et al., 2011). However, most empirical studies assume system homogeneity and overlook environmental influences. Conceptual frameworks qualitatively assess resilience, though their application in engineering systems remains limited (Komljenovic et al., 2020). Simulation-based methods model resilience behaviour via fuzzy models, Monte Carlo simulations, optimisation algorithms, and Bayesian networks (Tepes, Neumann, 2020; Tong et al., 2020). While widely used in critical infrastructure, they require extensive data and expertise, making them impractical for universal implementation (Karakoc et al., 2019; Ouyang, Wang, 2015). Conversely, index-based approaches provide a semi-quantitative assessment by aggregating predefined resilience metrics (Rehak et al., 2019; Guo et al., 2020). Studies have explored index models for community resilience (Kammouh et al., 2017; Renschler et al., 2019) and technical infrastructure (Storesund, et al., 2018; Guo et al., 2020), considering factors such as redundancy and response capacity. Given these methods, this study introduces a resilience index tailored to underground coal mining, integrating technical, economic, and organisational parameters with fuzzy methodologies to address uncertainties.
Methods
Resilience in systems is categorised into two main components: hard (technical performance) and soft (organisational and human factors in preparedness and recovery). Both aspects must be evaluated to ensure robust resilience. Reliability is a key measure of system preparedness (Youn et al., 2011; Rød et al., 2016), while maintainability (M), supportability (S), organisational resilience (OR), and economic resilience (ER) contribute to recovery (Yoon et al., 2017). Reliability ensures sustained performance under specific conditions (Yoon et al., 2017; Afrin, Yodo, 2019), and maintainability reflects the ability to restore operations within a given timeframe (Sarwar et al., 2018; Rød et al., 2016). Supportability refers to inherent system features enabling effective maintenance, divided into passive (spare parts, logistics) and active (workforce availability, diagnostics) elements (Sarwar et al., 2018; Hosseini, Barker, 2016). Organisational resilience helps maintain stability after disturbances (Omer et al., 2014), while economic resilience mitigates losses and supports sustainable growth (Wang et al., 2020; Rose, 2007).
This study introduces a resilience index based on these five fundamental aspects. In Step 1, reliability and maintainability are assessed using operational data. In Step 2, due to limited direct data, organisational resilience, economic resilience, and supportability are analysed using multi-criteria decision-making methods.
Steps to implement reliability and maintainability based on historical data
To quantify resilience, system constraints—such as repair feasibility, production capacity in different states, maintenance duration, and environmental conditions—must be defined. Reliability analysis involves collecting failure data, that is, time between failures (TBF) and time to failure (TTF) from various sources, alongside key covariates like maintenance type, shift schedules, and working conditions (Tortorella, 2015).
Various models assess the impact of these covariates on hazard rates. This study employs the proportional hazard model (PHM) for time-independent factors and the stratified Cox regression method (SCRM) for time-dependent influences. If the PH assumption holds, PHM is used; otherwise, SCRM is applied for data analysis. [1]
Where (t, z) are reliability functions; (column vector) shows the regression coefficient of the relevant n covariates, (z) (row vector) represents the impact of every variable on the hazard function, and R0 (t) is baseline reliability. In Equation 2, Rs (t,z) and R0s (t) show the hazard rate and baseline hazard in the i layer, respectively.
Finally, the baseline reliability function is determined. In general, when applying the baseline hazard rate, the risk factors do not affect the failure pattern; for this reason, the rate of baseline hazard is considered to be the same as the rate of hazard. This paper uses parametric models and stochastic processes to model the baseline hazard rate (Kumar, Klefsjö, 1994).
Historical data from the field, including TBF, must be gathered to determine baseline reliability. Then, to choose the best model to fit the TBFs data, the assumption of independent and identically distributed (iid) of the data must be determined. Using analytical or graphic methods can analyse the trend test (Barabady, Kumar, 2008). Hence, trend (Military handbook, Laplace, Anderson Darling, and Mann-Kendall) and autocorrelation (graphical method) tests must be done. If there is a trend in the data, the non-homogeneous Poisson process (NHPP) technique, such as the power law process (PLP), can be used for analysis. When there is no sign of trends in the database, and they are correlated, the homogeneous Poisson process (HPP), like the branch Poisson process (BPP), can be used. Otherwise, the classical statistics method, that is, the renewable process (RP), can analyse the collected data. In this research, to do trend tests, Minitab software was applied. According to this software, for each trend test, if its p-value value is more than a significant level (0.05), the null hypothesis of the test (the null hypothesis of all tests is the absence of the trend) is accepted; otherwise, the null hypothesis is not accepted, and the data has a trend. In the following, to do a series correlation test, the ith data of TBF is drawn in terms of (i − 1) h data of TBF in a two-dimensional space. If the drawn points do not have a specific order and are distributed sparsely, then the data are not correlated; in other words, if the drawn data are located along a line, they will be correlated (Garmabaki et al., 2016).
A novel index for resilience measure of critical infrastructure systems in underground coal mines
Operating environment and covariates such as reliability affect system maintainability. In this index, the proportional repair model (PRM) and the SCRM are used to consider the impact of environmental situations in the repair estimation. PRM is an extended PHM used to predict the extent to which a part is repaired according to covariates. As can be seen in Figure 1, if the PH assumption is not rejected, the PRM is chosen; otherwise, if time-dependent covariates can be classified, it can be applied to the SCRM for data assessment. PRM and SCRM are calculated based on Equations 3 and 4, respectively (Barabadi et al., 2011):
Where M(t, w) represents the repair and maintainability function, ε denotes the regression coefficient of the corresponding covariates (w), and M0 (t) defines the baseline repair rate and maintainability (the cumulative distribution function of time to repair, TTRs). In Equation 4, M0g (t) (t) indicates the baseline maintainability in the gth stratum. Finally, the same procedure was applied to reliability to determine the baseline maintainability function, and TTR data were utilised for maintainability analysis.
The code developed in Python software was used to perform all the steps mentioned in the reliability and maintainability indices.
Steps to implement supportability and organisational resilience-based expert judgment
In this section, a questionnaire must first be designed to collect the necessary data to analyse organisational resilience and supportability. Questions should be asked to determine the underlying factors' current status at the hierarchy's lowest level. People selected for interviews and surveys, in addition to having adequate knowledge about infrastructure, must also have sufficient experience in interacting with infrastructure. In the next step, the feedback received must be quantified. After quantifying the opinions of experts using the MCDM approach, these opinions
should be merged to reach a consensus on the current status of the factor.
The calculation method is as follows: when the number of experts is equal to Z, the fuzzy number representing the opinion of expert z regarding the condition of the i th most effective base factor is defined as:
where aiz, biz, ciz denote the lower, middle, and upper bounds of the expert’s assessment of factor i
The calculation method is as, when the number of experts is equal to Z. the fuzzy number from the point of view of z's expert on the condition of i's the most effective base factor is equal to piz = (aiz,biz,ciz) in the opinion of the most expert on the status of the first effective factor i, The output of aggregation of expert opinions on the current situation of the effective factor of i at the K level is obtained from Equation 5 (Zadeh, 1968).
Where, ai, bi, and ci show the lower, the middle, and the upper bound, respectively, which is the current situation of the i effective base factor at the K's level. Defuzzification is obtained from Equation 6 . The output of Equation 5 is considered as the probabilities of the effective base factor of the i at the K level
[5]
[6]
The probabilities of the influential factor j at the K-1 level are is also estimated using the weighted average of the probabilities of the base factors affecting that factor at the K-level level point as follows
In Equation 7, Pj indicates the probabilities of the influential factor j at the K-1 level, and n represents the number of effective
[7]
Figure 1—Process for calculating system resilience
A novel index for resilience measure of critical infrastructure systems in underground coal mines
base factors connected to the influential factor j at the K-1 level. Also, Wi represents the normalised weight of the effective base factor of the i at the K level. The weight coefficients of different levels show the importance of influencing factors. To calculate the weight of impacting factors, the fuzzy decision-making trial, and evaluation laboratory (Fuzzy DEMATEL) method as an MCDM approach were used. The calculation steps are detailed in Appendix A (Gabus, Fontela, 1972).
Case study
Shields in underground coal mines play a vital role in ensuring safe and efficient extraction of coal seams within the longwall system. Designed to support controlled roof caving while simultaneously protecting miners, these critical infrastructure (CI) systems provide structural stability and operational reliability. In this study, the shield system of the Tabas Longwall coal mine in Iran is examined using the proposed methodology (Figure 2). The mining shield—FAZOS 10/28 Poz, 10/28Poz/BSN—is engineered to function in longwall faces with longitudinal inclinations exceeding 12°, incorporating additional stabilising devices for enhanced performance. The system operates seamlessly in seams with longitudinal inclinations up to 12°, stabilising devices up to 30°, and transverse inclinations ranging from ± 15°. Its backward advance functionality ensures continuous efficiency in longwall mining operations. This shield system is meticulously designed to automate key mining processes, including:
➤ Establishing roof support with initial load-bearing capacity.
➤ Maintaining continuous load-bearing stability for roof protection.
➤ Releasing and advancing the support following each mining cycle.
➤ Adjusting the armored face conveyor (AFC) machine for optimal operation.
➤ Correcting canopy and support positions for improved structural integrity.
➤ Shielding the longwall front to ensure worker safety.
➤ Lifting the bases and stabilising the AFC for sustained performance.
A schematic representation of the shield system is presented in Figure 3, highlighting its core components, such as the canopy, wooden blocks, base, advancing ram, hydraulic legs, and other essential elements.
Figure 2—The location of the Tabas Longwall coal mine
Figure 3—A schematic view of the mine shield system
A novel index for resilience measure of critical infrastructure systems in underground coal mines
Resilience analysis of the shield system
Reliability, and maintainability indices
In the initial phase, data pertaining to the reliability and maintainability indices of the shield system must be systematically gathered. This dataset includes time-related parameters and covariates, which have been meticulously recorded over a period of approximately two and a half years. Table 1 presents the failure data of the shield system, while Table 2 provides details on the repair data, offering valuable insights into the system’s overall performance and maintenance trends.
As illustrated in Table 2 and Table 3, respectively, the columns TBF and TTR provide insights into the shield system’s performance across various environments. In the status column, a cell with a value of zero indicates a censored failure, whereas a value of one represents a confirmed shield failure. The remaining columns in the tables display covariates, which were collected through both quantitative and qualitative methods. For quantitative data, numerical values such as cut length (metres) and cut average (metres) were recorded. In contrast, qualitative data were gathered from multiple sources, including archived statistics, official documents, direct observations, and interviews with key personnel.
To accurately define the subsystem covariates, a comprehensive approach was taken—leveraging the expertise of managers and operators, conducting observations, analysing repair shop records
collected failure data of the shield system
1
Table 2
The collected repair data of the shield system
and reports, consulting maintenance teams, and incorporating field data. The categorised covariates are presented in Tables 3 and 4, detailing failure covariates and repair covariates, respectively.
The covariates of failure and repair operating environment of the shield system are statistically formulated, as shown in Table 5.
To evaluate the reliability and maintainability indices of the shield system, it is essential to consider the proportional hazards (PH) assumption and conduct the required tests outlined in Step 1 of Figure 1. Accordingly, all calculations were performed using custom-developed Python code to ensure precise analyses. The computed results for the reliability and maintainability indices of the shield system, based on the PH model, are systematically presented in Tables 6 and 7.
Table 3
Classification and quantification of failure covariates for the shield system
Covariates
Shift
Working place
Type of delay
Type of maintenance
Table 4
Classification (Qualification)
Morning (1)
Midday (2)
Night (3)
E0.face (1)
E3.face (2)
Mineral (1)
Mechanical (2)
Electric (3)
Strap (1)
Frame (2)
Classification and quantification of repair covariates for the shield system
Covariates Classification (Qualification)
Morning (1)
Shift
Working place
Type of delay
Table 5
Covariates
Midday (2)
Night (3)
E0.face (1)
E3.face (2)
Mineral (1)
Mechanical (2)
Electric (3)
Personnel
Classification (Qualification)
Captain (1)
Take care of the cable (2)
Mineral (3)
Mechanical (4)
Electric (5)
The covariates for the shield system failure and repair operating environment
Failure covariates Repair covariates
Shift (z1)
Working place (z2)
Type of delay (z3)
Type of maintenance (z4)
Cut (m) (z5)
Cut average height (m) (z6)
Shift (w1)
Working place shift (w2)
Type of delay shift (w3)
Personnel (w4)
Table 1
The
A novel index for resilience measure of critical infrastructure systems in underground coal mines
Table 6
Results rate proportional hazards model of reliability
Table 7
Results rate proportional hazards model of maintainability
The test statistic follows a Chi-square (1) distribution under the null hypothesis, where the covariate complies with the proportional hazards (PH) assumption. According to this hypothesis, the expected value of the test statistic is zero, and any deviation from zero may be statistically significant at predetermined significance levels, such as 0.01 or 0.05. If the p-value falls below these thresholds, the stratified Cox regression method (SCRM) should be employed instead. However, as indicated in Table 7, the p-values exceed both 0.05 and 0.01, confirming the validity of the proportional hazards model (PHM) for this analysis.
Following this confirmation, the actual reliability function for the shield system was derived using Equation 8. Ultimately, the resulting reliability curve for the shield system is depicted in Figure 4, providing valuable insights into its long-term operational performance. [8]
As illustrated in Figure 4, the reliability of the shield system decreases to 50% after 29 hours of operation, factoring in the influence of environmental conditions. Furthermore, after 100 hours of continuous operation, the system’s reliability declines to zero, indicating the need for maintenance or intervention to restore functionality.
As shown in Table 8, the p-values exceed 0.05 and 0.01, indicating that the PRM is accepted. Additionally, the
maintainability value of the shield system was obtained using Equation 9. Finally, the maintainability curve of the shield system based on the operating environment, is illustrated in Figure 5.
Figure 4—Shield system reliability
Figure 5—Shield system maintainability
A novel index for resilience measure of critical infrastructure systems in underground coal mines
As illustrated in Figure 6, the maintainability of the shield system has remained above 90% after 100 hours of operation, taking into account the effects of the operating environment. This stability highlights the system's resilience and reliability under various operational conditions.
Organisational resilience, supportability, and economic resilience indices
The concept of resilience plays a crucial role in enabling organisations to effectively respond to unanticipated events, particularly in volatile and uncertain environments (Mosoarca et al., 2019). The resilience of systems is influenced not only by the technology they incorporate but also by the organisations that manage those (Rehak et al., 2019). In this regard, considering the frequency of usage in previous studies, expert recommendations, and analytical assessments, the relevant factors of this index in underground coal mining were stratified (Appendix B) based on the following criteria: (a) Limited selection of impacting factors (b) Avoidance of redundant impacting factors (c) Preference for easily measurable parameters.
The organisational resilience index was structured around five key aspects: response and recovery (Luthans et al., 2015), absorption and reduction (Rehak et al., 2019), sense of ownership (Luthans et al., 2015), monitoring and prediction (Baroud et al., 2014), and commitment and resilience (Brown et al., 2017). If these aspects do not meet the desired standards within an organisation, both material and human resources may be ineffectively utilised in critical situations. Therefore, managers must take these influencing factors into account to enhance organisational resilience. To execute Step 2 of Figure 1 for analysing organisational resilience in underground coal mining based on the operating environment, questionnaires were distributed among personnel from 25 organisations, yielding 19 responses. Experts were then asked to evaluate the direct influence of row-based factors on column-based factors, as depicted in Table 1.
Subsequently, the Fuzzy DEMATEL method was employed to determine the weight of each factor. This was followed by calculating the probabilities of the impacting factors, resilience aspects, and overall organisational resilience. As illustrated in Figure 6, expert judgments indicate that response and recovery are the most critical aspects of resilience. However, nearly all aspects and influencing factors require improvement. Based on the findings, if the mine organisation experiences disruption (e.g., failure of the shield system), the probability of demonstrating resilience is 40.2%.
In alignment with the organisational resilience index rules, the aspects and influencing factors of the supportability index were carefully selected. Here, operational conditions (Hosseini, Barker, 2016; Sarwar et al., 2018; Tortorella, 2015) and system design (Tortorella, 2015) serve as the fundamental components of the supportability index (Appendix C). To establish the hierarchical structure of the shield system's supportability index, a comprehensive questionnaire consisting of 14 questions was developed to assess the state of key impacting factors. This questionnaire was completed by 14 preventive maintenance specialists and shield system operators. Subsequently, leveraging the outcomes of the survey, the probabilities of the primary influencing factors were determined. Additionally, using the Fuzzy DEMATEL technique, the weights of both aspects and individual impacting factors were calculated. Finally, in accordance with the proposed methodology, the probabilities of the supportability index and its generic aspects were computed. Figure 7 presents the calculation results, illustrating the weights and probabilities assigned to each parameter within the system. The analysis reveals that both aspects are equally significant and require improvements. Based on the findings, if the mine support section experiences disruptions— such as failures within the shield system—the probability of demonstrating resilience is estimated at 65. 7%.
Building upon the principles established for organisational resilience and supportability indicators, the aspects and influencing factors of the economic resilience index were carefully selected.
Figure 6—The results of the shield system organisational resilience index estimation
A novel index for resilience measure of critical infrastructure systems in underground coal mines
As illustrated in Appendix D, fixed pricing (Da Silva et al., 2021; Czaplicka-Kolarz et al., 2015; Wu et al., 2018) and employment (Da Silva et al., 2021; Klank, 2011) serve as the fundamental components of this index. Following the methodology outlined in previous steps, a structured questionnaire consisting of 12 questions was developed to assess the primary influencing factors within the shield system. This questionnaire was completed by 18 experts from the economic sector relevant to the study. Using the responses obtained from the survey, the probabilities of the basic influencing factors were calculated. Additionally, the weights of the aspects and impacting factors were estimated through the fuzzy mathematical technique. Finally, applying the proposed methodology, the probabilities of the generic aspects and the overall economic resilience index were determined. Figure 8 presents the calculated economic resilience index results for the case study, depicting the weight and probability of each parameter within the system. The findings indicate that both aspects hold nearly equal significance and require improvement. Based on the results, if the mine's economic sector faces disruption—such as a failure in the shield system—the probability of exhibiting resilience is estimated at 49.7%.
Presentation of the main shield system resilience index
The estimated values for resilience concepts were utilised to calculate the resilience index (Ri), as presented in Table 8. This table distinguishes between reliability and maintainability indicators, which are assessed over time (up to 100 hours), and organisational resilience, support capability, and economic resilience, which are evaluated at fixed time intervals. To establish a structured resilience assessment, five classes were defined. The ideal class—representing the highest level of resiliency—is assigned 100% of the weight, while the lowest class receives 10% of the total weight. Consequently, the Ri is computed as the summation of index probabilities, as formulated in Equation 10. A higher Ri value signifies greater resilience, whereas lower values indicate a more vulnerable state. Using the Ri computational model, the minimum resiliency rating is 10, and the maximum possible is 100. In the case of the shield system within the Tabas underground coal mine, resilience levels
were categorised into five distinct groups based on the Ri values, as detailed in Table 9.
According to Table 10 and Figure 9, the shield system demonstrates poor resilience, with its stability gradually declining over time. After 100 hours of operation, only 20%–30% of system failures are expected to be recoverable, allowing the water installation to resume normal functionality. Among the key indicators, reliability, maintainability, and supportability are in relatively good condition. However, organisational and economic resilience indexes exhibit major weaknesses, with most aspects and influencing factors falling below acceptable standards. Several contributing factors have led to this decline, including the absence
Table 8
Calculation of Ri for the shield system in the Tabas underground coal mine
Table 9
Classification of Ri
Figure 7—The results of the shield system supportability index estimation
Figure 8—The results of the shield system economic resilience index estimation
A novel index for resilience measure of critical infrastructure systems in underground coal mines
of coordinated and integrated policies, price intervention measures affecting the parts supply chain, weak economic diplomacy, and sanctions limiting access to essential replacement components.
To address these challenges, organisations must take proactive steps such as engaging mining personnel in company goal discussions, fostering a positive organisational atmosphere, and considering political and economic constraints. By implementing these strategies, the resilience of these indexes can be significantly improved.
Given the shield system's poor resilience, a series of corrective measures must be taken, including comprehensive training programmes, the employment of experienced professionals, and swift responses to spare parts maintenance and repair. Additionally, mine management should establish a specialised initiative to strengthen industry-academia collaboration, recognising that universities serve as critical foundations for developing skilled and specialised workforces. When academic expertise is effectively integrated into industrial production, it accelerates innovation, technological advancement, and economic growth.
Conclusion
This study introduced a novel resilience index (Ri) to assess resilience in underground coal mining, considering the impact of the operating environment. The analysis incorporated historical data and expert judgment, with data processing facilitated through a Python-based computational model. Additionally, the fuzzy set theory was applied to address potential uncertainties in expert evaluations. The proposed methodology accounts for multiple resilience indicators, including reliability, maintainability, supportability, organisational resilience, and economic resilience. To demonstrate its practical application, the model was implemented for the shield system in the Tabas Longwall coal mine, a vital component of underground mining operations.
Key findings from the study include:
➤ The operating environment significantly influences the shield system’s resilience.
➤ The shield system’s resilience declines over time.
➤ Organisational and economic resilience indicators exhibit weaker performance compared to reliability, maintainability, and supportability, leading to a substantial impact on overall resilience. Therefore, project managers should prioritise improvements in these two areas to enhance the shield system’s stability within the production system.
➤ Between 20% and 30% of system failures are likely recoverable.
➤ Based on the Ri, the shield system in the Tabas underground coal mine is classified as having poor resilience.
These findings underscore the critical need for strategic interventions to improve resilience in underground mining operations. Strengthening organisational and economic resilience, along with proactive maintenance strategies, will be key to ensuring sustainable and reliable mining performance.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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A novel index for resilience measure of critical infrastructure systems in underground coal mines
Appendix A
Obtaining average direct-relation matrices: utilizing fuzzy triangular number (TFN) (displayed in Table I and Figure 1), experts show the direct influence that parameter i exerts on parameter j. The TFN computes are that in first, second and third terms indicate the lower, middle, and upper bounds of TFN that shows the direct influence of parameter i on parameter j based upon the opinion of kth expert. The average direct relation matrix can be estimated by averaging the h expert’s value matrices as Equation 1:
Table 1
The correspondence of linguistic terms and linguistic values
Linguistic terms
Linguistic value
Very High Influence (VH) (0.75, 1.0, 1.0)
High Influence (H) (0.5, 0.75, 1.0)
Low Influence (L) (0.25, 0.5, 0.75)
Very Low Influence (VL) (0, 0.25, 0.5)
No Influence (NO) (0, 0, 0.25)
Obtaining normalised direct-relation matrix. Based on the matrix , the normal direct-relation matrix can be obtained (Equation 2) as follows:
Let be the elements of X and describe three crisp matrices, whose elements are obtained from X ~ as follows:
Drive the total relation matrix. The total relation matrix T is calculated as follows (Equation 4), where the identity matrix is indicated as I.
1—Linguistic variables
The elements of the matrix contain fuzzy triangular numbers as presented in the following Equation.5: [5]
Where elements are . According to the crisp case, the crisp elements of total relation matrices can be calculated as:
Set up the causal diagram. After acquiring matrix T, the sum of rows (D) (Equation 6) and the sum of columns (R) (Equation 7) of the total relation matrix can be calculated as follows:
Calculating the weight of the factor (Equation 8). The fuzzy weight of each parameter (w ~ i) can be calculated as follows:
[8]
Defuzzification weight of factors: to defuzzify weights of, the Best Non-fuzzy Performance (BNP) method (Equation 9) was used to defuzzify the values of D, R, and W ~ i as follows: [9]
Where l, m, and u show lower, middle, and upper bounds of TFN values, respectively
Figure
A novel index for resilience measure of critical infrastructure systems in underground coal mines
Appendix B
Appendix C
Appendix D
Figure 2—Factors for organisational resilience index
Figure 3—Factors for supportability index
Figure 4—Factors for economic resilience index
Affiliation:
1University of Venda, Department of Earth Sciences, Venda
Correspondence to: N. Rembuluwani
Email:
ndivhudzannyi.rembuluwani@univen. ac.za
Dates:
Received: 1 Aug. 2024
Revised: 12 Sep. 2025
Accepted: 10 Nov. 2025
Published: December 2025
How to cite:
Rembuluwani, N., Diko-Makia, L. 2025.
Assessing the current status quo of artisanal and small-scale mining in South Africa: Opportunities, challenges, and future directions. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 695–702
DOI ID:
https://doi.org/10.17159/2411-9717/3530/2025
ORCiD:
L. Diko-Makia
http://orcid.org/0000-0001-8101-0224
Assessing the status quo of artisanal and small-scale mining in South Africa: Opportunities, challenges, and future directions
by N. Rembuluwani1, L. Diko-Makia1
Abstract
Artisanal and small-scale mining is crucial for the mineral sector in South Africa, but it also presents both opportunities and challenges. This paper presents an overview of the South African artisanal and small-scale mining sector, the socio-economic significance of artisanal and smallscale mining, the regulatory environment, and the environmental impacts, which are currently the status quo of this sector in South Africa. The paper identified ways in which artisanal and small-scale mining can support local development, create employment opportunities, and reduce poverty. The case of informatisation, ecological damage, and social insecurity has shown social conflicts, potential land degradation, and criminal behaviour. Finally, the paper discusses the future of artisanal and small-scale mining in South Africa, which will largely depend on improved legislation, enhanced personnel capacity, and more sustainable practices to ensure that the positive outcomes of the industry outweigh the negative ones. These propositions include recommendations to all stakeholders, including the government, industry, and civil society, such as stricter environmental regulations, improved working conditions for miners, and the promotion of responsible mining practices.
Keywords
artisanal and small-scale mining; socio-economic significance; regulatory environment; local development; poverty alleviation
Introduction to artisanal and small-scale mining in South Africa
Artisanal and small-scale mining (ASM) plays a significant role in South Africa's mining landscape, contributing to employment, economic development, and mineral extraction. In the fourth quarter of 2023, the unemployment rate in South Africa was 32,1% (StatsSA, 2023), and the poverty level was at 55% of the general population (World Bank, 2020). Most mining communities are located in the poorest areas of South Africa, where alternative livelihoods are particularly complex (DMR, 2018). The ASM sector has the potential to employ these disadvantaged communities. However, ASM operations face various challenges, including informal practices, environmental degradation, and inadequate regulation. The sector's sustainability can help enhance the country's economic position by generating royalties and taxes (DMRE, 2022). Understanding the status quo of ASM in South Africa is crucial for identifying opportunities for improvement and sustainable development. While there is no universally recognised definition of artisanal and small-scale miners, the 2022 Artisanal and Small-Scale Mining Policy in South Africa, which outlines the rights and responsibilities of ASM operators, provides the following definitions for these terms:
Artisanal mining means traditional and customary mining operations using traditional or customary ways and means. This includes the activities of individuals who mainly use rudimentary mining methods and manual tools to access mineral ore, which is usually available on the surface or at shallow depths.
Small-scale mining means a prospecting or mining operation that does not employ specialised prospecting, mechanised mining technologies, chemicals, including mercury and cyanide, or explosives, or the proposed prospecting or mining operations do not involve investment or expenditure which exceeds such amount as may be prescribed (DMRE, 2022).
Overall, these definitions clarify the scale, methods, and technologies associated with artisanal and small-scale mining, helping to differentiate between these types of operations within the mining sector. Artisanal mining refers to a less formal and less sophisticated approach to mining, typically conducted by local communities or individuals with limited capital investment. Small-scale mining involves more organisation and planning than artisanal mining, but still requires a smaller scale compared to more extensive mining operations.
Assessing the status quo of artisanal and small-scale mining in South Africa
Artisanal and small-scale miners in South Africa extract a range of minerals, including clay, gravel, sand, aggregate, gold, diamonds, and gemstones. These miners typically work independently or in small groups, often in remote or rural areas where larger mining companies are absent. According to Munakamwe (2018), the population in the ASM sector generally comprises foreign nationals from Lesotho, Mozambique, and Zimbabwe, with their numbers exceeding that of locals. The demographics of the population in the sector include men, women, and children; Ledwaba et al. (2019) noted that these miners are of different ages and are primarily people of colour (Ledwaba, 2016). Their operations typically rely on manual labour, essential tools, and simple processing methods, and they are often informal, requiring formal regulation.
Historical background and evolution of ASM in South Africa
South Africa is renowned for its diverse range of minerals. It is the home to the largest deposits of chrome, manganese, platinum group metals, vanadium, and vermiculites (Debrah et al., 2014). However, artisanal and small-scale miners tend to focus more on gold, diamonds, and construction materials such as clay, gravel, sand, and aggregate (Mutemeri, Petersen, 2002). The ASM sector was first recognised post-apartheid in South Africa. The country's mining history mainly focused on large-scale mining companies, although there has been evidence of ASM operations (Mintek, 2016; Ledwaba, 2017).
ASM in South Africa was largely overlooked during apartheid (Solomon, 2012), however, it was identified by the Reconstruction and Development Programme (RDP) as one of the vital socioeconomic programmes to benefit from the new government (Government Gazette, 1994). In the spirit of stimulating entrepreneurial culture and better utilisation of mineral resources, ASM was earmarked to address the imbalances of apartheid (ANC, 1990; Kekana, 1999). The assistance to the ASM sector included skills development, financial support, technical aid, and access to mineral rights (Government Gazette, 1994).
In 1998, the white paper on the Minerals and Mining Policy of South Africa's small-scale mining section centred on the following pillars: developing the ASM sector, encouraging the participation of previously disadvantaged communities, and addressing the sector's challenges. In 2002, the Mineral and Petroleum Resources Development Act (MRPDA) was developed to formalise the ASM sector, focusing mainly on environmental issues, licensing, labour relations, and rehabilitation. The MPRDA was perceived to be biased towards large mining companies because the ASM sector lacked the resources to implement the requirements of the act (African et al., 1994; Solomons, 2012; Fakir, 2016), although some of the issues are being addressed (Ledwaba, Nhlengetwa, 2015).
The ASM sector has shown considerable growth since 1994, with several participants estimated to be between 10,000 and 30,000 (Mutemeri, Peterson, 2002; Buxton, 2013). According to the Department of Mineral Resources (DMRE), over 1,000 permits were issued between 2004 and 2010. In 2011, the Mine Health and Safety Council estimated that there were 1,030 registered smallscale miners. ASM activities in South Africa are primarily located in rural communities with access to mineral resources. However, there is a high involvement rate in poverty-stricken provinces, such as Limpopo, the Northern Cape, Northwest, and Eastern Cape (Ledwaba, 2017), where the unemployment rate is also high (StatsSA, 2016).
Importance of ASM to the South African economy and society
For 150 years, mining has been the backbone of the South African economy (Baxter, 2015; DMR, 2015). In 2023, the mining industry contributed R202.1 billion in gross domestic product and employed 475,561 South Africans (StatsSA, 2023). Large mining companies dominate 90% of the South African mining industry, with the artisanal and small-scale mining sectors comprising the remaining 10% (Lundu, 2014). In the past, the South African government had developed policies that disadvantaged ASM while favouring large mining companies (African et al., 1994; Solomons, 2012; Fakir, 2016). This limited employment opportunities for rural and poor communities, as they often lack the skills required by large mining companies (Ledwaba, 2017; Jansen, 2017; Hentschel et al., 2003). Before democracy, the policies mainly catered for a minority population. However, infusing ASM into the economy can help boost the local economy. The ASM sector is known to utilise rudimentary tools that are mostly locally crafted, which is essential for enhancing local purchasing power.
According to the fourth quarter of Stats SA (2023), the unemployment rate stood at 32.1%. The labour-intensive nature of the ASM sector can help to provide jobs for rural unemployed communities (Thwala et al., 2023). The sector is estimated to support 44 million people through direct employment and 136 million in industries that support the sub-sector worldwide (World Bank, 2022; IISD, 2017; Perks, McQuilken, 2020). In South Africa, the sector is estimated to employ 30,000 people, although it is believed that the number has grown substantially (Mutemeri, Peterson, 2002; Buxton, 2013; Ledwaba, 2015; Ledwaba, Nhlengetwa, 2016). Buxton (2013) states that the ASM sectors employ ten times more people than the extensive mining industry. The ASM sector focuses on minerals that are deemed uneconomic for large mining companies. Large mining companies primarily focus on exploiting large deposits, leaving a niche for the ASM sector to mine, which provides employment (Kaufmann et al., 2019; Kesari et al., 2020). This sector has the potential to contribute to addressing the country's unemployment rate.
Legal
and regulatory framework
Overview of the legal framework governing ASM in South Africa
The legislation that addressed mining issues in the past was the MPRDA of 2002; this legislation was biased in favour of large mining companies. DMRE, in March 2022, developed and published a policy for the ASM sector to legalise the industry; the policy has taken a holistic approach to addressing ASM-related issues, focusing on fostering industry sustainability. One of the most significant challenges of the MPRDA of 2002 was that it covered issues of both ASM and large mining companies under one umbrella, which could have been more favourable for the ASM sector. Section 27 of the MPRDA deals with licensing, which is prohibitive to the development and growth of the industry. The issues covered in the MPRDA include environmental management, water use, land use, health and safety, and the provision of required financial resources.
Analysis of relevant legislation, policies, and regulations affecting ASM operations
In 2022, the Ministry of Mineral Development developed a policy specifically addressing the ASM sector. The first point of the
Assessing the status quo of artisanal and small-scale mining in South Africa
ministry's call was to define the concepts of artisanal and smallscale mining, so as to gain a better understanding of the sector. The threshold for investment was one million rand for artisanal miners and 10 million rand for small-scale mining, with a provision for graduation between the categories based on increased levels of investment. The act also proposed a dual licensing process, which involved a first-come, first-served basis, with consultation with the Council of Geosciences (CGS). The CGS is mandated to provide geological data that may be used to demarcate areas where the ASM sector can mine. Furthermore, the council will also assess the water and land risks, minimising the possible risks that the ASM sector can pose to the environment. Preference will be given to South Africans and cooperatives during the area reservation process. Other pieces of legislation that ASM need to adhere to include the following:
Income tax
Mining companies are liable for various taxes, including income tax, capital gains tax, withholding tax, VAT, transfer duty, and securities transfer tax, as per the Income Tax Act of 1967. The Artisanal and Small-Scale Mining (ASM) industry is also required to pay taxes and royalties, contributing to socio-economic growth, despite the informal nature of the sector, which often obscures its revenue contributions.
Health and safety
The Mine Health and Safety Act of 1996 governs the health and safety practices in mines. The act primarily focuses on ensuring a safe working environment, including the provision of required health and safety equipment by mining companies, the appointment of a health and safety representative, and the development of mine health and safety policies. As attractive as all this may seem, some of the provisions of the act do not necessarily apply to the ASM sector, as they lack the expertise and resources to implement them.
Environmental management
A suite of legislation governs ecological issues in South Africa, including the National Environmental Management Act of 1998, the Mineral and Petroleum Resources Development Act of 2002, the Environmental Impact Assessment (EIA) guidelines of 1997, the Environmental Conservation Act of 1986, and the National Environmental Management Act of 1998. An application for environmental authorisation in South Africa can range from R1,000 to R10,000 per requirement, covering EIA, scoping, biodiversity assessment, integrated permitting system, and amendments. However, these costs do not include the expenses associated with hiring an environmental practitioner. Implementing this legislation is costly and is seen as a barrier to entry into the mining sector. Additionally, requirements include developing an environmental management plan and setting aside funds for rehabilitation.
Water management
The Department of Water Affairs has developed guidelines for water use in small-scale mining, with the National Water Act of 1998 serving as the primary legislation for enforcing water management. Best Practice Guideline A1 categorises water use depending on impact as high, medium, or low, where the water use activity with high impact requires a license to use water, medium impact requires general authorisation, and the one with low impact requires no license.
Labour
relations
South Africa's key employment law statutes include the Labour
Relations Act of 1995, the Basic Conditions of Employment Act of 1997, the Employment Equity Act of 1998, and the Skills Development Act of 1998. These laws safeguard workplace rights and promote economic development, fair labour practices, peace, democracy, and social development. While some requirements of these statutes pertain to fundamental human rights and are relatively straightforward to adhere to, the artisanal and small-scale mining (ASM) sector, due to its informal nature, often does not comply with any of these acts (Mutemeri, Peterson, 2002).
Challenges, gaps, and prospects in the regulatory framework and enforcement
The reasons for the ASM sector not adhering to the pertaining laws include a lack of knowledge of the laws, a limited understanding of the implications, and insufficient resources to implement such legislation (Ndlazi, 2021). On the government side, the main challenge with legislation is the lack of enforcement and monitoring. Small-scale miners also believe that there is a lack of institutional support, funding, market access, infrastructure, and land availability. Currently, the Directorate of Small-Scale Mining lacks collaboration with other government departments and resources to support the ASM sector.
The Artisanal and Small-Scale Mining Policy of 2022 will serve as a beacon of hope for the ASM sector. It addresses the issues overlooked in the MPRDA, the structure of this policy, and individual issues that have affected the ASM sector in the past. The issues addressed in this policy include application systems, resource constraints, limited access to DMRE offices, and difficulty in accessing information and securing funds. According to the speech given by the Minister of DMRE in 2022, Mintek trained 630 artisanal miners between 2019 and 2021 in four provinces: Gauteng, Mpumalanga, Northern Cape, and North-West. They are also training 200 women to operate as artisanal and small-scale miners. In January 2024, at the emerging miners' symposium, the deputy minister also indicated that the DMRE facilitated and opened funding opportunities for ASM, intending to fund 13 miners, with priority being given to women. This is being done in collaboration with the Industrial Development Corporation (IDC). In promoting inclusion, DMRE has committed R40 million towards exploring minerals for the ASM sector to access and mine ore bodies. With this level of government support, the ASM sector has a genuine opportunity to thrive in South Africa
Environmental, health, and social impacts of ASM
The ASM sector has shown substantial growth and benefits in poverty alleviation in poor communities. Still, it is also known to significantly impact the environment and the health of workers and the surrounding communities (Telmer, Stapper, 2007). Artisanal and small-scale mining (ASM) can have significant environmental impacts due to various factors inherent in its operations. The impacts include deforestation, land degradation, river siltation, solid waste disposal, landscape impairment, water pollution, acid mine drainage, and mercury and cyanide contamination (Elmes et al., 2014; Isidro et al., 2017; Lobo et al., 2015; Mhangara et al., 2020; Fianko, Boadua, 2021; Macháček, 2019).
Although it is acknowledged that health risks are significant and access to occupational health services is limited (Tsang, 2019; Hentschel, 2002), there remains a lack of comprehensive descriptions of the actual occupational hazards associated with artisanal and small-scale mining (ASM) (Howlett et al., 2023). Due to the lack of proper safety measures and equipment, miners
Assessing the status quo of artisanal and small-scale mining in South Africa
in ASM face numerous occupational hazards, such as accidents, injuries, and fatalities. Working in confined spaces, collapsing roofs, handling explosives, and operating machinery without adequate training can increase the risk of accidents (Kyeremateng-Amoah et al., 2015; Singo et al., 2022; ILO, 2015; Rupprecht, 2015).
Water pollution
ASM operations can contaminate water sources with chemicals such as mercury and cyanide, as well as other pollutants used in the extraction and processing of minerals (Hilson, 2003). Other impacts include the depletion of water resources, increased levels of siltation, turbidity, and heavy metal content, as well as disturbance of aquatic life and its habitats (Mujere, Isidro, 2016).
The pollution of water due to mining affects the health of the community, particularly the residents living near the mines, as rural communities often lack access to municipal water facilities and rely on river water for domestic purposes (Lobo et al., 2016; Heath et al., 2004; Taux, 2022).
Deforestation and habitat destruction
Before any mining activity commences, vegetation needs to be removed to access the ore. This removal of vegetation results in the loss of biodiversity and the destruction of local ecosystems and habitats, leading to the decline of wildlife (Harlow et al., 2019; Siqueira-GayJuliana et al., 2020; Sonter et al., 2018; Mhangara et al., 2016).
Soil erosion and land degradation
The ASM sectors is not known for rehabilitation, and the removal of vegetation can lead to soil erosion, which depletes the soil's fertility (Magidi, Machingo Hlungwani, 2022; Obodai et al., 2023).
Air pollution
Mining and processing activities, such as blasting and crushing, can release particles into the air, which can pollute the environment, resulting in respiratory problems for the public (White et al., 1991; Csavina et al., 2012; Schwarzenbach et al., 2010; Tavares et al., 2017; Silva-Rêgo et al., 2022).
Land reclamation and rehabilitation
The ASM sector does not invest in land reclamation and rehabilitation. They leave the mining sites dilapidated, leaving behind pits that pose a health and safety risk due to physical and chemical wastes (Mhlongo, Amponsah-Dacosta, 2016; Kim, Jung, 2004; Rodrıguez, 2011; Mhlongo, Akintola, 2021).
Economic contribution and challenges
Contribution of ASM to the South African economy
ASM is labour-intensive, enabling the sector to employ a large number of people. The sector is estimated to support 44 million people through direct employment and 136 million in industries that support the sub-sector worldwide (World Bank, 2022; IISD, 2017; Perks, McQuilken, 2020). South Africa is estimated to employ approximately 30,000 people, although it is believed to have grown substantially (Mutemeri, Peterson, 2002; Buxton, 2013; Ledwaba, 2015; Ledwaba, Nhlengetwa, 2016).
Most people involved in ASM are from impoverished communities with complex alternative livelihoods, so this sector provides them with an opportunity to support their families. In the current economic climate, where securing employment for graduates is daunting, it should be even more challenging for those without formal education, hence, people often turn to ASM at the
subsistence level. ASM sectors also focus on minerals extraction deemed uneconomic by large mining companies, resulting in minimal overlap between this sector and large mining companies (Zvarivadza, Nhleko, 2018).
Most families in Africa are led by women who must ensure that there is food on the table for the family; the ASM sector has shown substantial growth in employing women from rural communities (Hilson, Garforth, 2012, 2013; Arthur-Holmes, Abrefa Busia, 2022; Arthur-Holmes et al., 2022). The ASM sector in South Africa is contributing to improved living standards for low-income communities by providing affordable construction materials, including clay, aggregate, sand, and gravel (Kaufmann et al., 2019). Focusing on the diversity of minerals, the sector provides technical skills and employment opportunities for local communities (Kesari et al., 2020).
Challenges faced by the ASM sector
Over the years, challenges confronting the ASM sector have been well-documented. These problems include limited access to mineral deposits, lack of appropriate skills and technology, limited access to capital and markets, and lack of institutional support (Nellie, Petersen, 2002; Hoadley, Limpitlaw, 2004; Department of Mineral Resources (DMR), 2011; Ledwaba, Nhlengetwa, 2016; DMR, 1998; Love, 2015). These challenges are discussed in the following:
➤ Limited access to mineral deposits and markets – the absence of policies that address the ASM sector specifically has resulted in the sector operating outside the legal domain, which limits their access to mineral deposits and markets (Mutemeri, Peterson, 2010). Love (2015) noted that miners find the process cumbersome, even in countries where ASMspecific legislation is in place. The fact that these miners operate illegally leaves them vulnerable to intermediaries and forces them to sell their products at less than market value (Mutemeri, Peterson, 2002; Ledwaba, 2017; Nhlengetwa, 2019).
➤ Lack of appropriate skills and technology – the sector is primarily poverty-driven, resulting in minimum investment in mining and processing technologies (Mutemeri, Peterson, 2010; Mutemeri, Peterson, 2002; Ledwaba, 2017). These circumstances also result in a lack of finances for training. Hence, they rely on indigenous knowledge systems for mining, processing, and business management.
➤ Limited access to capital – artisanal and small-scale miners mainly operate outside the legal domain, which hinders them from getting financial support from lending institutions and governments (Ledwaba, 2017; Heath et al., 2004). This traps the miners in a vicious circle of poverty.
➤ Lack of institutional support – artisanal and small-scale miners are from the poorest communities and lack representation in senior government offices where policies are made (Nhlengetwa, 2019; Heath et al., 2004). This results in them being discriminated against.
Gender dynamics in ASM
According to the Mineral Council of South Africa (2020), women represent 12% of South Africa’s total mining labour force of 454,861 people. Of this number, there is no representation of women in small-scale mining. Although there is limited literature on women's involvement in ASM in South Africa, 40%–50% of the African workforce in ASM comprises women (Weldegiorgis et al., 2018; Ofosu et al., 2022). The ASM sector is often viewed as a
Assessing the status quo of artisanal and small-scale mining in South Africa
male-dominated industry in South Africa, with the involvement of women being overlooked (Bester, 2019; Munakawe, 2018; Chuma, 2021). The Word Bank (2019) also noted that no empirical data on women's involvement in ASM is available county-to-county. Women play various roles in ASM, contributing to the sector's operations and supporting livelihoods within mining communities. Women often engage in ore processing activities. However, women employees at ASM sites typically do not have access to the more profitable tasks, such as "digging or excavation" and "supervision," as noted by Koomson (2019). This is because such roles are often viewed as masculine (Danielsen, Hinton, 2020). Besides being miners, women are also engaged in various activities, including petty trading, food vending, bar management, and operating shops (Geenen et al., 2022).
Women are heads of households worldwide (Nwosu, Ndinda, 2018), with 42% of children living with their mothers only (StatsSA, 2021). Their involvement in artisanal and small-scale diamond mining (ASDM) also helps women generate income to support their families. The ASM sector accounts for 17.4% of the South African workforce (StatsSA, 2018), and nearly 50% of its workforce comprises women (Dladla et al., 2022). One of the benefits of women’s involvement in the ASM sector is that it enhances their resilience and ability to cope with potential economic shocks (Den Haan et al., 2020).
Women's challenges in the ASM sector include economic, legal, cultural norms and taboos surrounding sexuality, institutional, and decision-making (USAID, 2020). In Sub-Saharan Africa, men in the ASM sector feel that women are inferior, resulting in limited access to productive and management roles (Buss et al., 2019; Hinton, 2016). This results in an income gap between men and women in the ASM sector, with women working longer hours as well as facing challenges in accessing resources, finance, and ownership; hence, they get paid less than their male counterparts (Eshun, 2016; LahiriDutt, 2018; Buss et al., 2017, 2019; Yakovleva, 2007; GEM, 2012; AMDC, 2015). Hausermann et al. (2020) highlighted that women face exploitative challenges where they are coerced into sexual activities with miners, which not only violate women but leave them prone to severe physical and mental health challenges (USAID, 2019).
In numerous developing countries, subsurface mineral acquisition is governed by legal and customary tenure systems, where customary tenure takes precedence, and women face greater difficulties in obtaining mining and mineral rights (Deere, Leon, 2003; Buss et al., 2017). Hence, women opt to work illegally, which
SWOT
Strengths
• Provides employment and income.
• Resource accessibility.
• Community engagement.
• Health and safety issues.
leaves them more vulnerable to intermediaries. Even though there are numerous challenges for women in the ASM sector, they still forge their way in the industry; this is evident in Rwanda and Uganda, where women are showing potential to obtain higher income than men in the same contexts (IGF, 2018; Yakovleva, 2007; Buss et al., 2019).
Future directions and recommendations
Table 1 presents a SWOT analysis summarising the state of the ASM sector. It can assist stakeholders in understanding the dynamics of the sector, allowing them to leverage its strengths, address its challenges, capitalise on its opportunities, and mitigate threats.
After reflecting on the current state of the ASM sector in South Africa, the following future directions and recommendations are proposed. These include strategies to help develop the sector aim to address the identified challenges that the sector faces. The primary objective of this section is to lay the groundwork for the sustainable growth and success of the sector.
Formalisation and regulation
With the development of the new ASM policy in 2022, this policy is a ray of hope for the ASM sector because it covers a wide range of issues that used to hinder the sector's sustainability. The country will also be better positioned to benefit from the sector by collecting royalties and taxes. With the possibility that most artisanal smallscale miners will be registered, the government will be in a better position to enforce legislation that benefits the environment.
Gender-sensitive approach
Since most households in South Africa are headed by women, strategies that are gender-sensitive and can assist women’s growth in the industry need to be developed. More research is needed on women's involvement in ASM.
Capacity building
The government should support the sector by providing capacity-building initiatives to improve technical skills, promote entrepreneurship, and comply with legislation. In doing this, the sector stands a fighting chance in the current economic climate.
Stakeholder engagement
The government needs to facilitate dialogues between ASM miners, NGOs, large mining companies, and educational institutions in order to develop ways in which the sector can be assisted.
Weaknesses
• Informality and lack of regulation.
• Flexibility and adaptability.
• Environmental impact.
• Economic instability. Opportunities Threats
• Formalisation and regulation.
• Technological advancements.
• Market expansion.
• Community development.
• Regulatory challenges.
• Environmental and social risks.
• Market fluctuations.
• Health and safety risks.
Table 1
analysis for the ASM sector
Assessing the status quo of artisanal and small-scale mining in South Africa
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Affiliation:
1School of Mining, University of the Witwatersrand, South Africa
Correspondence to: T.C. Maswanganyi
Email: tinyikocm@yahoo.co.uk
Dates:
Received: 21 Sept. 2024
Revised: 3 Jun. 2024
Accepted: 25 Nov. 2025
Published: December 2025
How to cite: Maswanganyi, T.C., Smith, G.L., Minnitt, R.C.A. 2025. Identifying strategic gaps and opportunities in sustainable development initiatives within the South African mining industry. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 703–710
DOI ID:
https://doi.org/10.17159/2411-9717/3143/2025
ORCiD:
G.L. Smith
http://orcid.org/0009-0006-4799-4032
Identifying strategic gaps and opportunities in sustainable development initiatives within the South African mining industry
by T.C. Maswanganyi1, G.L. Smith1, R.C.A. Minnitt1
Abstract
This paper identifies the strategic gaps and opportunities for the South African mining industry’s contribution towards advancing sustainable development. Mineral resources companies are confronted by a range of complex social performance challenges, which largely manifest in sporadic community and labour unrest, undermining the sustainability and profitability of these companies. Integrating supply chain management, strategic long-term planning and sustainability planning is identified as a strategic gap that can contribute towards the sustainability of mining companies, if effectively implemented. Contributing towards sustainable development by the South African mining industry is not merely a voluntary requirement on the industry but a legal requirement in terms of the Minerals and Petroleum Resources Development Act No. 28 of 2002. This Act is legislation aimed at advancing socioeconomic development in communities that host mining operations and in areas that provide labour to the South African mining industry. In contributing towards the advancement of sustainable development in mining host communities, not only will mining companies fulfil a legal requirement in terms of the Minerals and Petroleum Resources Development Act, but they will also prevent negative social and economic impacts in those communities. This paper identifies innovative and cost-effective ways of advancing sustainable development by integrating strategic supply chain management, strategic long-term planning, and sustainability planning.
Managing mining operations in South Africa has never been so complex due to increased unemployment and deprivation in communities that host mining operations, higher mining operating costs, mining-related legislation, and the volatility of commodity prices. Social performance and the broader environmental, social and governance (ESG) requirements enacted upon the mining industry are increasing as the demand for minerals increases to support a transition to low-carbon energies amongst other requirements (Verrier et al., 2022).
According to Verrier et al. (2022), the mining industry should seek to go beyond obtaining the social licence to operate and integrate sustainable development (SD) into their strategic long-term plans and strategic supply chain plans.
This paper describes how key elements of strategic supply chain management and sustainability planning can be integrated into the strategic long-term planning process of mining operations to close a strategic sustainability gap that is required to advance SD.
According to Smith (2011), a strategic long-term plan is defined as “the anticipated life of mining operations across a mining right under a given set of long-term planning parameters and strategic intent”. Integrating SD into strategic long-term plans implies that mining companies should strategically include relevant, sustainable development goals (SDGs) as parameters when conducting feasibility studies on mining operations. Integrating SD into strategic long-term plans should happen during feasibility studies and throughout the life of mine (LoM) to leverage on scale benefits while maximising a mining company’s contribution towards advancing SD and preventing potential social unrest, which can be hugely disruptive to mining operations. It is imperative that mining companies develop strategic supply chain plans that seek to leverage their procurement spend to support employment and enterprise
Identifying strategic gaps and opportunities in sustainable development initiatives
development in host communities, as outlined in this paper. A strategic supply chain plan should be aligned with strategic long-term plans to be effective. Socio-economic development (SED) plans that are integrated into the LoM, on the other hand, will enable gradual but incremental transfers towards SD from the revenues of mines and those of their suppliers suppliers over the LoM. This notion is consistent with social and labour plans (SLP) legislated through the Minerals and Petroleum Resources Development Act No. 28 of 2002 (MPRDA). To be effective, these socio-economic parameters should be integrated during the development of a mineral asset and maintained throughout the LoM. It is in the best interest of mining companies and their suppliers to contribute towards advancing SD and sustainable mining operations to prevent detrimental.
Sustainability and sustainable development
The concept of sustainable development (SD) has attracted attention in different forms both at a global level, with the United Nations (UN) General Assembly adopting Sustainable Development Goals (SDGs) in 2012 at the Rio + 20 Summit (UN, 2012). According to the Brundtland Report (UN, 1987), sustainability is “meeting the needs of the present generation without compromising the ability of future generations to meet their own needs”. Sustainability and SD are used interchangeably in this document as they are in most sustainability literature and in practice.
In 2012 at the Rio + 20 Summit (“The Future We Want”), the UN General Assembly adopted the following expansive definition of sustainable development (UN, 2012):
“We also reaffirm the need to achieve sustainable development by: promoting sustained, inclusive and equitable economic growth, creating greater opportunities for all, reducing inequalities, raising basic standards of living; fostering equitable social development and inclusion; and promoting integrated and sustainable management of natural resources and ecosystems that support inter alia economic, social and human development while facilitating ecosystem conservation, regeneration and restoration and resilience in the face of new and emerging challenges.”
If the UN definition of SD and the related SDGs are to prevail, innovative approaches to SD must be sought. It is worth noting that the UN General Assembly’s expansive definition of SD as outlined in the aforementioned, incorporates the sustainable management of natural resources and ecosystems to support economic, social, and ecological imperatives. This indicates how broad and essential
the concept of sustainability is and how relevant it is to the South African mining industry. Sustainability can also be broadly defined as a continuance, and as such, this paper is inspired by the need for the much-needed continuance of South African mining activities and operations while advancing SD, resulting in mutually beneficial shared value for several stakeholders in the mining industry such as host communities and shareholders.
According to the aforementioned definitions of sustainability, the broader scope of SD includes economic, social, and environmental elements. The scope of this paper is, however, limited to the economic and social elements of SD. It also outlines the role of strategic supply chain management, sustainability planning, and strategic long-term planning in advancing SD by the South African mining industry.
Not only is extensive academic research on sustainability and sustainable development reliant on the UN’s SDGs and the related definitions of sustainability as defined in the aforementioned (Dvorakova, Zborkova, 2014; Cuba et al., 2014; Kopacz et al., 2017; Monteiro et al. 2019; Guillen-Gosalbez et al., 2019; Alves et al., 2019; Roukonen, 2020) but organisations also measure their performance against sustainability goals based on SDGs. To this end, most companies have increased their focus on SD to the extent of ensuring representation of the sustainability functions within executive structures of organisations up to board level and the integration of sustainability performance indicators into their annual reports over and above financial and productivity reporting. Good health and well-being (SDG 3), quality education (SDG 4), industry innovation and infrastructure (SDG 9), sustainable cities and communities (SDG 11), and partnerships for the goals (SDG 17) are key examples of SDGs that are of paramount importance to the mining industry as the industry needs a healthy and educated workforce from host communities and beyond.
Innovative solutions are key to ensuring that the mining industry remains sustainable and profitable while driving socio-economic development in communities that host mining operations. The UN’s 17 SDGs (UN, 2020) as adopted by 193 heads of state and governments at the 2015 UN Sustainable Development Summit (UN, 2015) are summarised in Figure 1.
The South African mining industry must therefore leverage partnerships with the government and its supplier base amongst other relevant stakeholders (SDG 9 and SDG 17). The ultimate goal should be to support social and economic development in mining host communities to reduce economic dependency on mines as mineral resources are depleted. Sustainability planning
Figure 1—United Nations 17 SDGs (Source: United Nations Department of Economic and Social Affairs, 2020)
Identifying strategic gaps and opportunities in sustainable development initiatives
within mining companies comprises, amongst other imperatives, identifying and financially providing for social and economic initiatives for the benefit of mining host communities and labour providing communities.
This sort of socio-economic development usually comprises infrastructure development (SGD11), clean water and sanitation (SDG 6), and decent work and economic growth enabled through enterprise and skills development. Leveraging sustainability planning parameters over the LoM will considerably advance SD in mining communities through infrastructure development and job creation.
Sustainable development from a South African perspective
The UN General Assembly’s definition of SD is even more relevant to South Africa’s socio-economic environment, which is characterised by inequalities, deprivation, and unemployment. According to the Organisation for Economic Co-operation and Development (OECD), South Africa’s unemployment rate reached 34.5% in 2022, while the country represents one of the highest inequalities in the world, with the wealthiest 10% holding 85.6% of the net wealth (OECD, 2022). According to Stats SA the unemployment rate has reduced slightly by 0.2% to 32.7% during the fourth quarter of 2022 (Department of Statistics, 2023). This represents one of the highest unemployment rates in the world, with the expanded definition of unemployment, including those who are not actively seeking employment, reaching 42.7% in the same period. The gravity of socio-economic challenges has increased in South Africa in recent years, and the impact of COVID-19 has reportedly regressed the SD efforts such as decent work and economic growth (SDG 8) achieved prior to the pandemic as the South African economy experienced a significant decline in gross domestic product (GDP), which is a measure of economic activity. South Africa’s GDP is reported to have declined by 6.4% in 2020 relative to a 0.2% growth in 2019, the largest decline in economic activity since 1946 (Department of Statistics, 2022).
In a journal article entitled, “Creating shared value as a business strategy for mining to advance the United Nations Sustainable Development Goals”, Fraser (2019), states that SDGs are reflective of goals that are common and beneficial to both the mining industry and host communities in a global context. Such goals, as stipulated in the 17 SDGs include educated and healthy communities, access to water, energy and infrastructure. Similarly, and in a South African context, Cole et al. (2021) have effectively demonstrated the consistency of the MPRDA with the SDGs by identifying 15 SDG dimensions that are also socio-economic levers in the MPRDA. Advancing SD is therefore not only consistent with advancing SDGs, but it also fulfils the requirement of the MPRDA, which is a legal requirement that seeks to reduce poverty and inequality both in communities that host mining operations and areas that provide labour.
Against this background, there are compelling reasons to embrace and be guided by the principle of the UN’s SDGs and the related definitions of sustainability to enable the much-needed contribution to sustainable development by the South African mining industry.
Accordingly, the International Council on Mining and Metals (ICMM) has developed 10 SDG-related principles for mining companies with several South African mining companies having become members of the ICMM. ICMM advocates for integrating the 10 principles, including the advancement of social performance and the engagement of stakeholders on SD, into the corporate strategies of mining companies (ICMM, 2003).
Despite several mining companies subscribing to ICMM principles and being members of the ICMM, mining companies have not been able to effectively implement ICMM principles for the advancement of SD (Tuokuu et al., 2019; Andrews, Essah, 2020). Andrews and Essah (2020) cite mining induced social and environmental issues to include social displacement, mass displacement, loss of livelihoods, acid mine drainage, noise, dust, air, and water pollution. These issues are consistent with those cited by Tuokuu et al. (2019) in a South African context.
Continual community protests prevalent in mining host communities and the numerous amendments to the Mining Charter and related court battles indicate increased expectations for the industry (Minerals Council South Africa, 2020).
Strategic supply chain management
According to Fawcett et al. (2007), an ideal supply chain value chain extends from an organisation’s suppliers’ suppliers to customers’ customers, where the supply chain of a focal organisation should manage the flow of information and materials across the entire supply value chain. Managers typically associate supply chain management (SCM) with better information exchange, shared resources, and win-win relationships among members of a supply chain (Fawcett et al., 2007). According to Monczka et al. (2018), “a supply chain is a set of three or more organisations linked directly by one or more of the upstream or downstream flows of products, services, finances, and information from a source to a customer”. Inevitably, supply chains involve a tremendous flow of funds, the value of which can be strategically managed to enable profitability and SD, including social performance. As such, this view of supply chains presents an opportunity to leverage the procurement expenditure across supply chains to support employment. Inclusive procurement is defined in Table 1 of this paper, and enterprise development, amongst other imperatives for the advancement of SD.
SCM has evolved from a transactional purchasing function into a strategic function to include sub-functions such as strategic sourcing, inventory management, environmental, social, and governance (ESG), enterprise and supplier development (ESD), and inclusive procurement, resulting in more complexity and a need for effective management and collaboration within supply chains. An organisation's supply chain management function has become a compelling source of competitiveness. More and more companies compete based on the efficiency of their supply chains (Gurzawska, 2019). Capabilities and opportunities that are prevalent within supply chain networks, including local industrialisation, enterprise and supplier development, and inclusive procurement amongst other supply chain related levers, can significantly support the advancement of SD.
Effectively integrating social performance objectives into feasibility studies, supply chain strategies, strategic long-term plans and the corporate strategies is therefore imperative for the sustainability of mining companies as it can result in cost-effective ways of contributing towards SD over an LoM.
The strategic long-term planning process integrates numerous long-term planning parameters to optimise the value of a mining business, and as such, the strategic integration of the corporate strategy, strategic supply chain, sustainability, and strategic longterm planning strategies of a mining business is imperative, as illustrated in Figure 2. The ultimate goal should be to develop robust and effective supply chain and sustainability strategies that contribute towards job creation, inclusive procurement,
Identifying strategic gaps and opportunities in sustainable development initiatives
enterprise development, and social performance through long-term planning, sustainability planning, and supplier partnerships. This approach will result in impactful and lasting SD beyond mining, contributing towards socio-economic development while reducing unemployment, poverty, and community unrest. Securing the social licence to operate by mining companies is imperative and can be achieved through the effective contribution towards SD by these companies.
Integrated framework for advancing SD through strategic supply chain management and strategic long-term planning
Strategic supply chain management can be an effective enabler of SD, more so when its strategic nature and potential long-term impact is leveraged and aligned with strategic long-term planning and sustainability planning processes, as reflected in Figure 3. Figure 3 depicts the key dimensions of the strategic SD enablers, being strategic long-term planning, strategic supply chain and sustainability planning. According to the conceptual framework reflected in Figure 3, strategic supply chain and sustainability planning requirements should be integrated into strategic long-term planning parameters. These key dimensions are further described in Table 1. Dimensions, such as long-term planning, can potentially contribute to a mineral asset's sustainability and economic value as sustainability parameters are added to the long-term plans of mining companies and provided for financially. Enhancing the existing strategic long-term planning framework to incorporate strategic supply chain and sustainability planning requirements effectively is therefore imperative for the sustainability of South African mining companies.
Through its procurement spend, which reached R451.9 billion in 2021 (Minerals Council, 2022), the mining industry can effectively advance SD by ensuring that an increased portion of this spend is directed towards skills development, enterprise development, job creation, and corporate social responsibility (CSR) in mining host communities.
1In clarifying the difference between corporate strategy, strategic long-term planning and sustainability planning – corporate strategy is the overall business strategy that defined business goals. Strategic long-term planning integrates numerous long-term planning parameters to optimise the value of a mining business and sustainability planning sets out goals to enable a mining company’s contribution to sustainability.
This can be achieved by placing contractual obligations on suppliers to the mining industry that requires them to direct a portion of this expenditure towards implementing the strategic supply chain dimensions reflected in Figure 3. Contractual obligations should not only be included in supply agreements between mining companies and their suppliers, but they should also be monitored.
Following here is an explanation of the lack of integration, which has been identified as a strategic gap and opportunity for improvement that needs to be addressed to enable the advancement of SD by the South African mining industry:
➤ Mining companies tend to apply a reactive approach to sustainable development due to the lack of proactive sustainable development and long-term sustainability planning (Katz, Pietrobelli, 2018; Fraser, 2019; Verrier et al., 2022). In addressing this gap, mining companies should provide for the advancement of SD in their strategic longterm plans to support the sustainability of mining operations throughout the LoM. This implies that each mining company should invest in adequate resources and partnerships to enable the advancement of SD and the sustainability and profitability of mining operations at the beginning of the LoM.
➤ Strategic long-term plans of mining companies focus largely on technical and commercial parameters that are aimed at maximising financial return on investment (ROI), and such plans do not effectively incorporate long-term sustainable development and strategic supply chain plans (Katz, Pietrobelli, 2018; Fraser, 2019; Soupajarvi, Kantola, 2020; Verrier et al., 2022). Ghost mining towns that remain after mining operations have ceased, high unemployment, and underdevelopment in mining communities in South Africa are testament to this assertion (Marais et al., 2018; Marais, De Lange, 2021). Figure 2 and Table 1 reflect the dimensions that should be integrated into strategic long-term plans to enable economic value and SD.
➤ Inherent misalignment between strategic long-term planning, strategic supply chain management, and sustainability planning in mining companies continue to undermine these companies’ potential to contribute towards SD (Soupajarvi, Kantola, 2020; Verrier et al., 2022). Strategic long-term
Figure 2—Transforming the supply chain management strategy into impactful SD strategy and plans1
Figure 3— An illustration of integrated sustainability management
Identifying strategic gaps and opportunities in sustainable development initiatives
Table 1
Dimensions of strategic supply chain management, strategic long-term planning, and sustainability planning
Organisational enabler/function
Strategic supply chain (SC) management
Dimension
Inclusive Procurement
Strategic long-term planning
Enterprise and supplier development (ESD)
Description
Inclusive procurement is aimed at increasing procurement spend with small businesses and those owned by previously marginalised individuals, thereby diversifying a company’s supply chain. Inclusive procurement is reported to have originated in the 1960s (MSDUK, 2014).
Enterprise development focuses on financial and non-financial support to small businesses that are not existing suppliers to a mining company to enable them to enter the supply chain of mining companies.
Supplier development focuses on supporting and growing procurement spend on small businesses that are in the supply chain of mining companies. This group of suppliers are supported mainly through preferential procurement and favourable payment terms, amongst other means.
Sustainability planning
Local employment
Supplier partnerships
Strategic cost management and competitiveness
Host community economic participation
Long-term planning
Business value optimisation
Scenario planning incl.
business case vs. social impact analysis
Economic factors and risk analysis
Socio-economic development (SED) plans
Stakeholder engagement plans
Social risk management
SED partnerships
Advancing local employment by placing a requirement on existing or prospective mining industry suppliers to include local labour as part of their staff compliment.
Defined as a requirement on suppliers to contribute towards skills development, local employment, enterprise development, preferential procurement and CSR.
Optimising the total cost of ownership of purchased goods and services within a supply chain.
Promoting economic activity in a mining host community by enabling supply chain activities closer to mining operations. Distribution, maintenance and repair operations, and certain manufacturing activities can be brought closer to mining operations.
Qualitative and quantitative consideration of long-term planning parameters pertaining to deriving value from a mineral asset over an LoM. Parameters such as metal prices and the cost of developing and operating a mineral asset are considered during long-term planning. It is imperative for mining companies to incorporate social performance, sustainability planning, and strategic supply chain parameters into their strategic long-term planning process (Smith, 2011)
Economic evaluation of a mineral asset in pursuit of an optimal NPV and ROI usually over the life of a mineral asset. NPV and ROI calculations should incorporate social performance and strategic supply chain management parameters.
Analysis and selection of various potential options to optimise NPV, ROI,SD and PESTLE analysis.
Consideration of economic factors such as the selling price of minerals and the risk analysis related to the minerals markets, countries that host mining operations.
The planning and implementation of infrastructure projects by a mining company (MPRDA, 2002).
In the context of the mining industry, a stakeholder engagement plan means the continual engagement of local community and government structures on social and developmental issues.
Effective risk assessment on social and developmental issues and on how these can impact mining operations.
Effective collaboration with potential partners such as local government, suppliers, universities and other companies is essential.
planning should incorporate social performance plans and performance monitoring of social plans throughout the LoM (Smith, Brooks, 2018; Suopajarvi, Kantola, 2020).
➤ According to Smith and Brooks (2018), the ability to balance the trade-off between a higher net present value (NPV)
estimate and social risk profiles can be of great value to decision makers in the development process of mining projects. More mining companies should also seek ICMM membership and implement ICMM principles within their organisations.
Identifying strategic gaps and opportunities in sustainable development initiatives
A combination of strategic long-term planning, strategic supply chain management and sustainability planning can be hugely instrumental in the advancement of SD, if effectively integrated and leveraged as potential enablers of SD by mining companies.
The strategic and effective integration of these three strategic enablers or functions within mining companies is imperative to ensuring considerable sustainable development. This integration needs to be effected in a manner that does not undermine the overall NPV and ROI of mining operations. South African mining companies should leverage their purchasing power by encouraging their supplier base to contribute towards socio-economic development in mine communities through inclusive procurement and enterprise development, amongst other levers.
According to the Minerals Council South Africa, the mining industry achieved a combined expenditure of R365.7 billion and R451.9 billion on goods and services during 2020 and 2021, respectively (Minerals Council, 2022). This expenditure can significantly enable SD when effectively leveraged, not only through enterprise development, inclusive procurement, and employment efforts by mining companies and their suppliers but also through other strategic partnerships such as partnerships with funding institutions. Enterprise development and inclusive procurement are effective instruments for advancing SD (SDG 8), amongst others.
Conclusion
This paper has shown that there is a need for the advancement of SD in mining host communities to reduce deprivation in those communities (SHRC, 2016; United Nations, 2020). Contributing towards the advancement of SD in mining host communities by the South African mining industry is described not only as a voluntary sustainability initiative but also as a legislated requirement in South Africa in terms of the MPRDA, which is aimed at advancing socioeconomic development. Despite the alignment in the objectives of the SDGs and the MPRDA, unacceptable levels of deprivation are prevalent in mining host communities as high value minerals continue to be extracted near these communities. Consequently, sporadic community unrests undermine the sustainability of mining operations and host communities. This paper contributes by describing the integration of strategic supply chain management, strategic long-term planning, and sustainability planning enablers or levers as a strategic gap and a novel solution for addressing this problem.
As discussed in this paper, strategic long-term planning should not only take a long-term view in optimising technical and economic long-term parameters needed for the economic exploitation of mineral assets over the LoM, but it should also effectively incorporate parameters for the advancement of SD. Mining assets return value to shareholders over their LoM, and strategic long-term planning is hugely instrumental in optimising the value of the economic return. In the same manner, SD can be effectively advanced in mining host communities over the life of mineral asset, if effectively integrated into the strategic long-term plan of a mine.
In addition, strategic supply chain management needs to be integrated early into strategic long-term plans to effectively leverage the purchasing power of mining companies over the LoM for the advancement of SD. Through this integration, targets for the contribution towards SD by suppliers to the mining industry should be set and planned for, well in advance and monitored. Strategic supply chain management can effectively enable the advancement of
SDGs through enterprise development and inclusive procurement, if effectively leveraged and integrated with strategic long-term planning and sustainability planning. It is in the best interest of both mining companies and their suppliers to contribute towards advancing SD and reducing the impact of community unrest. This will result in mutually beneficial relations amongst stakeholders and sustainable mining operations. Enhancing the existing strategic long-term planning framework to incorporate strategic supply chain and sustainability planning requirements is imperative for the sustainability of South African mining companies. This is a potential research topic in mineral economics.
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DIVERSITY
Identifying strategic gaps and opportunities in sustainable development initiatives
ABOUT THE SHOWCASE
The Southern African Institute of Mining and Metallurgy (SAIMM) invites you to a transformative event that reimagines the future of diversity and inclusion in the minerals industry.
Join us as we re-imagine the revitalised Diversity and Inclusion Committee, with a dynamic programme designed to spark dialogue, foster collaboration, and celebrate inclusive excellence.
The purpose of this event is to re-imagine the Diversity and Inclusion Committee of SAIMM, aiming to:
• Increase awareness of diversity and inclusion across the sector
• Engage members in meaningful dialogue and action
• Foster a culture of belonging and equity within SAIMM and the broader industry
RE-IMAGINING DIVERSITY AND INCLUSION
ONE DAY SHOWCASE 2026
Where to From Now?
Date: 12 May 2026
Venue: Southern Sun Rosebank
PROGRAMME OBJECTIVES
• Encourage Awareness: Launch initiatives and educate members on the value of Diversity and Inclusion.
• Drive Engagement: Involve members through workshops and committee participation.
• Create Safe Forums: Enable open discussion of Diversity and Inclusion issues.
• Celebrate Excellence: Recognize successful Diversity and Inclusion practices and inspire adoption.
WHY IT MATTERS
The Diversity and Inclusion Committee is central to building a welcoming, inclusive culture in the minerals industry. This launch event sets the foundation for long-term commitment, innovation, and transformation.
Affiliation:
1Department of Microbiology, University of Nigeria, Nsukka, Nigeria
Correspondence to: C.K. Ezeh
Email: ezechristian.kelechi@gmail.com
Dates:
Received: 2 Feb. 2024
Revised: 4 Feb. 2025
Accepted: 25 Nov. 2025
Published: December 2025
How to cite:
Eze, C.N., Ugwoju, N.M., Nnabuife, O., Enemuor, S.C., Okechukwu, V., Ezeh, C.K. 2025. Bioleaching and beneficiation of agbaja iron ore using Providencia vermicola KUBT-1 under varying process conditions. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 711–718
DOI ID: https://doi.org/10.17159/2411-9717/3268/2025
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1 under varying process conditions
by C.N. Eze1, N.M. Ugwoju1, O. Nnabuife1, S.C. Enemuor1, V. Okechukwu1, C.K. Ezeh1
Abstract
In this study, the efficacy of Providencia vermicola KUBT-1 in the leaching and beneficiation of Agbaja iron ore was evaluated under varying conditions of temperature, ore particle size, and pH. Agbaja iron ore is a Nigerian low-grade ore containing about 43%–52% iron and a high amount of gangue materials, including phosphorus (1.4%–2.0%) and sulphur (0.12%). The study was organised in triplicate in shake flasks with 48 samples. One millilitre of washed cells of Providencia vermicola KUBT-1 suspended in normal saline at 0.5 McFarland standard (108 cells ml-1) was introduced into each flask containing 50 g of sterilised ore in 100 ml of bioleaching medium, and the samples incubated at room temperature for eight weeks. The levels of upgraded iron, mobilised sulphur, and phosphorus were determined by atomic absorption and ultraviolet spectrophotometric analyses, respectively. Results showed that a particle size of 0.8 mm was optimal for iron upgrading and sulphur mobilisation while 1.0 mm ore size was optimal for phosphorus mobilisation. Up to 89.60% of the iron was upgraded while phosphorus and sulphur were mobilised, leaving residual values of 0.223% and 0.02%, in the ore, respectively. The organism produced best beneficiation results at a pH of 2.5 and a temperature of 3ºC. Correlation analysis with the Pearson’s correlation model showed a positive correlation between iron upgrading and sulphur-phosphorus removal (r =1.000, and r =0.967), respectively. These results present Providencia vermicola KUBT-1 as a promising candidate for large scale leaching and beneficiation of Agbaja iron ore.
Keywords
bioleaching, beneficiation, iron ore, gangue, mobilisation
Introduction
Agbaja iron ore is one of Nigeria’s iron (Fe) ore reserves. Nigeria is rich in natural resources, including iron ore reserves, and estimates of iron ore deposits stand in excess of 2.5 billion tonnes (Alafara et al., 2005). Agbaja iron ore is a low-grade ore containing approximately 47.50% Fe content and is located on a plateau at Agbaja, Kogi State. The ore has unusually high levels of phosphorus (1.66%) and sulphur (0.12%), which are significant setbacks to its utilisation in the blast furnace for steel production. Phosphorus and sulphur are responsible for steel brittleness, causing it to fracture at very low stress values. The conventional froth flotation technique for removing gangue from iron ore has not succeeded with phosphorus because phosphorus is bonded with iron (Uwadiale, 1983; Anyakwo, Obot 2010). Phosphorus and sulphur removal is essential to get high-quality steel with phosphorus and sulphur levels within the acceptable ranges of 0.010–0.020 wt% and ≤ 0.03 wt%, respectively (Kudrin, 1985).
For many years, certain chemolitotrophic bacteria (particularly the chemolitotroph, Acidithiobacillus ferrooxidans) have been used commercially to extract some metals from low-grade ores (Singleton, 1998). This process, also called biomining or bioleaching, attracts greater attention today because many of the sources of richer ore have been exhausted. High-grade ores are more amenable to extraction through conventional hydrometallurgical and pyrometallurgical procedures; for low grade ores, these techniques provide low metal extraction due to high process and energy costs. Such mining techniques also cause serious air, water, and land pollution. Water drainage from abandoned mines is acidic and has soluble metals contaminating waterbodies and land. In low grade ore mining, industries focus on cost-effective, low energy consuming and environment-friendly technology, one of which is bioleaching (Wasim, 2019).
Biohydrometallurgy or bioleaching uses microorganisms to extract metals from sulfides and/or iron-bearing ores. Here, either the metabolic activities of the microbe or its metabolic products are
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
utilised to convert insoluble metal sulfides to soluble metallic forms, which can then be recovered later through electrolytic and other processes (Singleton, 1998). Presently, bioleaching is widely applied to recover metals from low-grade ores as well as from tailings because it is simple, cost-effective, and ecofriendly (Tao et al., 2021). However, the shortcoming associated with bioleaching is its slow rate compared to chemical leaching. However, waste consumption as substrate by bioleaching organisms during biooxidation is an additional process benefit.
Microbes produce organic and inorganic acids that extract metals by deriving energy from this. Bioleaching effectively reduces capital costs and ecological pollution as it precludes the need for supplementation with toxic substances.
Also associated with phosphorus are the problems of strong primary segregation during the solidification of castings and the formation of high phosphorus brittle streaks between metal grains, impeding plastic deformation (Anyakwo, Obot 2010). Numerous research activities on the bio-beneficiation of low grade iron ores have been going on for decades now. Delvasto et al. in 2005 used the bacterium Burkholderia caribensis isolated from Brazilian high-phosphorus iron ore. They mobilised between 5%–20% of the phosphorus initially contained in the ore in 21 days of treatment in shake flask cultures. In 2008, Aspergillus niger, isolated from Nigeria’s Agbaja iron ore, was used to remove phosphorus from the same ore and in 49 days of leaching, up to 81% removal was achieved (Anyakwo, Obot, 2008). Agbaja iron ore needs to be upgraded in terms of increasing the weight per cent of iron per unit gramme of the ore as well as the removal of sulphur and phosphorus, which, due to their presence, led to the iron ore being abandoned in the past. For these reasons, this work has been designed to study the bacterial leaching and beneficiation of Agbaja iron ore under varying process conditions.
Materials and method
Bioleaching organism
The bioleaching and beneficiation organism used in this study was isolated from the iron ore. The use of organisms indigenous to the ore has some advantages as it precludes delays in the adaptation time of the organism to the system.
Iron ore
The Agbaja iron ore sample was collected from the National Development Centre in Jos, Nigeria. The iron ore was pulverised, sieved and separated into five different grain sizes: 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm and 1.0 mm.
Media
Two media, designated A and B, were mixed in a ratio of 1:0.5 for bacterial isolation and bioleaching experiments. Medium A was a 9K medium (Zhang et al., 2020), composed in g l-1 of (NH4)2SO4 3 ml, K2HPO4 0.5 ml, MgSO4.7H20 0.5 ml, KCl 0.1, Ca(NO3)2 0.014 ml, and de-ionised H2O 1000 ml. Medium B was nutrient broth.
Analytical equipment
Atomic absorption spectrophotometer (AA 7000) and UV spectrophotometer were used to evaluate residual iron and phosphorus/sulphur, respectively. The analyses were conducted at the Energy Centre, University of Nigeria, Nsukka.
Isolation and identification of bioleaching organism
Two hundred grammes (200 g) of pulverised Agbaja iron ore sample
was dispensed into each of three 250 ml conical flasks containing sterilised mineral salt medium, as described earlier, and nutrient broth. The pH was adjusted to 2.5 using 0.4 ml of concentrated sulphuric acid (H2SO4). After incubation for 7 days at room temperature (25°C–28°C), 0.1 ml of the supernatant from each flask was used to inoculate triplicate petri dishes of nutrient agar by the spread plate method. The inoculated plates were incubated for 24h under room temperature. The organisms that grew were subcultured on a freshly prepared nutrient agar and later transferred to nutrient agar slants. The bioleaching heterotrophic bacterium (a chemoorganotroph) was identified by 16S rDNA gene sequencing (Delvasto et al., 2006b) as Providencia vermicola strain KUBT-1.
Confirmation of Fe, P, and S levels in the ore
Analysis to confirm the already documented levels of Fe, P, and S in Agbaja iron ore was carried out using atomic absorption (AA7000) and UV spectrophotometers.
Bioleaching and beneficiation experiments
Experiments to determine the effects of particle size, pH, and temperature on the rates of biobeneficiation and upgrading of Agbaja iron ore lasted for eight weeks. The analyses were performed every two weeks. Parameters of particle size (0.2 mm, 0.4 mm, 0.6 mm,
0.8 mm, and 1 mm), pH (2.5, 5, 7, 9, and 11) and temperature (20°C, 25°C, 30°C, 35°C, and 45°C) were used in triplicates. Fifty grammes (50 g) of Agbaja iron ore was weighed into three 250 ml conical flasks for each particle size, pH and temperature. The ore samples were sterilised at 121°C for 15 minutes for three consecutive days. One hundred millilitres of sterilised mineral salt medium and 50 ml of nutrient broth were poured into each flask containing the iron ore. One millilitre (1 ml) of the washed cells of Providencia species suspended in normal saline to a level of 0.5 McFarland standard was introduced into each flask. A total of 48 flasks were used, and they were loosely covered with cotton wool and set in an orbital shaker operated at 150 rpm. Samples were collected every two weeks for analysis using atomic absorption and ultraviolet spectrophotometers to determine iron, phosphorus, and sulphur levels.
The weight percentage of mobilised phosphorus and sulphur was determined as follows in Formulae 1 and 2:
The result of the 16S rDNA sequencing (Devasto et al., 2006b) identified the isolate as having 95.20% pairwise identity with Providencia vermicola KUBT – 1 with NCBI accession number KX098543.
Results and discussion
Bioleaching isolate
The bioleaching isolate identified as Providencia vermicola KUBT-1 through 16S rDNA sequencing analysis (Devasto et al., 2006b) is a chemoorganotroph (heterotroph) and its use in bioleaching adds novelty to this work since its leaching potentials have not been harnessed or reported in previous studies. Previous works over the years have focused on the use of chemolithotrophs such as Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans in metal leaching works both in the laboratory and open field (Di
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
Spirito, Tuovinen 1982; Konishi et al., 1992; Choi et al., 1993; Hang et al., 1994; Garcia et al., 1995; Schnell, 1997; Fowler, Crundwell 1998; Singleton, 1998; Fowler, Crundwell 1999; Kelly, Wood, 2000; Brierly, Brierly, 2001; Jain, Sharma 2004; Ponce et al., 2012; Yang et al., 2013; Gao et al., 2020; Zhang et al., 2020).
Biobeneficiation of Agbaja iron ore
Results of the biobeneficiation experiments (dephosphorisation and desulphurisation) are depicted in Figures 1 to 6. Figure 1 shows the effects of ore grain size on the rate of phosphorus mobilisation by Providencia vermicola KUBT-1. There was a consistent increase in the percentage of mobilised phosphorus as the ore size increased until it reached an optimum at an ore size of 1.0 mm. The pH and temperature were kept at constant levels of 2.5 and 30oC, respectively. When other factors were kept constant and the pH
varied, a pH of 2.5 was optimal for phosphorus mobilisation (Figure 2) throughout the eight-week beneficiation experiment. A slightly different trend was noted for sulphur mobilisation (Figures 4 and 5) with respect to the effect of ore grain size. A particle size of 0.8 mm and pH of 2.5 were best for desulphurisation by the bioleaching bacterium.
The effects of temperature on biobeneficiation (biological removal of impurities) are reported in Figures 3 and 6. A temperature of 30oC is seen to be optimal for dephosphorisation and desulphurisation. The optimal mobilisations of phosphorus (P) and sulphur (S) from the ore occurred at ore grain sizes of 1.0 mm and 0.8 mm, respectively (Figures 1 and 4), a pH of 2.5 (Figures 2 and 5), and temperature of 30oC (Figures 3 and 6), portray the organism as an acidophilic mesophile. Reports from previous studies show that most microorganisms used in biohydrometallurgical processes
Figure 2—Percentage of phosphorus mobilised by Providencia vermicola KUBT-1 at varying pH levels
Figure 1—Percentage of phosphorus mobilised by Providencia vermicola KUBT-1 at varying ore grain sizes
Figure 3—Percentage of phosphorus mobilised by Providencia vermicola KUBT-1 at varying temperature levels
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
are acidophiles (Di Spirito, Tuovinen 1982; Hang et al., 1994; Bosecke, 1995; Gehrke et al., 1998; Adeleke et al., 2010; Liao et al., 2019; Liao et al., 2021). Many of them produce organic and inorganic acids during the reaction, and these acids assist the leaching process, leading to mobilisation/removal of the elemental contaminants. Hydrogen ion concentration (pH) and temperature have been reported to be essential factors in the leaching process, as both affect the dissolution rate of the ore (Alafara et al., 2005).
The iron ore originally contained about 1.66 Wt% P and 0.12 Wt% S. At the end of the eight-week beneficiation experiment, the ore was left with residual values of 0.223% P and 0.02% S, amounting to 86.7% and 83.3% of mobilised phosphorus and sulphur, respectively. Particle size affected the reaction rate by
modifying the surface area for the attack of microbial enzymes.
Even though a residual value of 0.223% P is still above the metallurgically acceptable P level for high-quality steels, which is between 0.010–0.020 wt%, it stands out as a rare feat accomplished by this new bioleaching organism, Providencia vermicola KUBT–1. From these results, the three factors tested (ore particle size, pH, and temperature) affected phosphorus and sulphur mobilisations.
Bioleaching/upgrading
of Agbaja iron ore
Results of the iron upgrading experiments are reported in Figures 7 to 9. The percentage of upgraded iron was highest at a particle size of 0.8 mm, pH of 2.5, and a temperature of 30oC, which were the same conditions for optimal mobilisation of sulphur
Figure 4—Percentage of sulphur mobilised by Providencia vermicola KUBT-1 at varying ore grain sizes
Figure 5—Percentage of sulphur mobilised by Providencia vermicola KUBT-1 at varying pH levels
Figure 6—Percentage of sulphur mobilised by Providencia vermicola KUBT-1 at varying temperature levels
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
and phosphorus (Figures 1 to 6). Using the Pearson’s correlation model, a positive correlation was noted between iron upgrading, phosphorus, and sulphur mobilisation (Figures 10 and 11).
The bioleaching organism in this study could solubilise up to 89.60% of the iron at the end of the eight-week bioleaching experiment in a liquid medium. According to Wasim et al. (2019), natural ores of several metals, including Ni, Zn, Fe, As, and Cu,
generally exist in metal sulphide forms, which are insoluble in neutral and weak acidic conditions. Oxidation of ferrous to ferric and sulphide into sulphate is required for bioleaching and is carried out by acidophilic microbes.
The leaching mechanism can be illustrated thus:
Figure 7—Percentage of iron upgraded by Providencia vermicola KUBT-1 at varying ore grain sizes
Figure 8—Percentage of iron upgraded by Providencia vermicola KUBT-1 at varying pH levels
Figure 9—Percentage of upgraded iron by Providencia vermicola KUBT-1 at varying temperature levels
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
This mechanism is direct bioleaching and involves a direct transfer of electrons from iron sulphide to the bacterial cells adhering directly to the metal surface, usually through an extracellular polymeric substance (EPS) produced by the organism (Wang et al., 2018; Wasim et al., 2019; Ye et al., 2021).
From the results of iron bioleaching (upgrading) presented in Figures 7, 8, and 9, optimal solubilisation of the iron sulphide still occurred at a particle size of 0.8 mm, acidic pH (pH 2.5), and mesophilic temperature (30oC). The foregoing has helped to largely delineate the bioleaching capabilities of Providencia vermicola KUBT -1, and its potential for use in large-scale leaching and beneficiation of the Nigeria Agbaja iron ore.
Conclusions
Bioleaching and beneficiation of metals is not a new technology. On the other hand, it has existed for many decades, continuously undergoing improvements in both methods and materials. It offers a viable and better alternative for tackling low grade metal ores. In this study, the chemoorganotrophic bacterium Providencia
vermicola KUBT-1, isolated from the ore, was found to be endowed with intriguing bioleaching and beneficiation capabilities for the upgrade of the Nigeria Agbaja iron ore laden with high levels of phosphorus and sulphur. Up to 89.60% of Fe was solubilised while the Wt% of phosphorus and sulphur were significantly (P < 0.05) reduced from 1.66 Wt % P and 0.12 Wt% S to 0.223 Wt % and 0.02 Wt %, respectively. Factors such as ore grain size, pH, and temperature were found to play important roles in the bioleaching and beneficiation rates of the iron ore.
In the current quest to find a solution to the impurities in the Agbaja iron ore, this study has further highlighted the presence of indigenous microbes in the ore of which their bioleaching and beneficiation potentials can be exploited to upgrade this valuable resource.
Acknowledgements
Special thanks go to the laboratory technicians of the Department of Microbiology, University of Nigeria Nsukka, for their cooperation and hard work towards the success of this study.
Figure 10—Graph of correlation showing the relationship between the level of iron upgraded and phosphorus mobilised by Providencia vermicola KUBT-1
Figure 11—Graph of correlation showing the relationship between the level of iron upgraded and sulphur mobilised by Providencia vermicola KUBT-1
Bioleaching and beneficiation of Agbaja iron ore using Providencia vermicola KUBT-1
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Affiliation:
1Council for Scientific and Industrial Research, South Africa
2Mine Health and Safety Council, South Africa
Correspondence to:
S. Khan
Email: skhan2@csir.co.za
Dates:
Received: 13 Nov. 2024
Revised: 6 Oct. 2025
Accepted: 25 Nov. 2025
Published: December 2025
How to cite:
Khan, S., Magweregwede, F. 2025. A review of circular economy opportunities in the mining sector. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 719–724
DOI ID:
https://doi.org/10.17159/2411-9717/3603/2025
ORCiD:
S. Khan
http://orcid.org/0000-0002-6362-5361
F. Magweregwede
http://orcid.org/0000-0002-4824-2266
A review of circular economy opportunities in the mining sector
by S. Khan1, F. Magweregwede2
Abstract
Circular economy opportunities for the mining sector are presented in this paper. A literature review was undertaken, followed by qualitative data gathering through survey questionnaires and unstructured interviews, and stakeholder engagements through workshops. The circular economy opportunities were identified and categorised according to the three circular economy principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems.
Opportunities aligned with the first principle include increased ore extraction efficiency processes, water recovery and recycling, substitution of raw materials, technology and waste utilisation for carbon capture and biotechnology. The second principle includes opportunities such as zero waste-to-landfill strategies, repurposing of mine waste, re-mining of tailings, recycling metals and processing of residues, and urban mining of electronic waste. Opportunities aligned with the third principle include the adoption of renewable energy, green hydrogen production, repurposing of post mining landscapes, and eradication of alien invasive vegetation.
Furthermore, the challenges of implementing circular economy in the mining sector are discussed. The current rate of waste generation from mining activities far exceeds the rate of reuse and repurposing. Recycling of large tyres and characterisation of hazardous electronic waste also pose challenges.
The most implementable circular economy opportunities in the mining sector are those aligned with the second principle of keeping materials in use. The high impact opportunities aligned with the first principle of designing out waste and pollution, and the third principle of regenerating natural systems, are more difficult to implement as they require large investments.
Keywords
circular economy, circular economy opportunities, mining sector, keep materials in use, design out waste, regenerate natural systems
Introduction
The circular economy (CE) concept has gained traction in recent years as a model for sustainable resource use, which promotes socio-economic development. A CE is defined as a systematic approach to economic development designed to benefit businesses, society, and the environment (EMF, 2017). In contrast to the linear take-make-dispose economic model, a CE promotes “keeping materials and products in circulation for as long as possible through practices such as re-use and repurposing of products, sharing of underused assets, repairing, recycling, and remanufacturing” (Schroder, 2020). The International Council on Mining and Metals (ICMM) (2023) noted that “a circular economy results from mining processes that minimise, re-use and ultimately eliminate waste, and from product design and collection processes that harvest and re-use metals indefinitely” (Figure 1).
The CE is supported by three principles, namely (DST, 2019; ACEA, 2018; ICMM, 2016):
i. Designing out waste and pollution.
ii. Keeping products and materials in use.
iii. Regenerating natural systems.
Businesses, including mining companies, are under pressure to transition to more sustainable business models to fulfil South Africa’s commitment to the 2030 Agenda for sustainable development and to achieve their net-zero targets. Based on the three principles that underpin a CE, the model could
A review of circular economy opportunities in the mining sector
potentially support this transition by designing out waste and pollution from business/mining processes, keeping products and materials in use for as long as possible, and regenerating natural systems (Suchek et al., 2021; DST, 2019; ACEA, 2018; ICMM, 2016).
The objective of this paper is to provide a high-level overview of some of the CE opportunities for the South African mining sector as well as the associated challenges. The contents of this paper have been extracted from a study done by Khan et al. (2021), detailed in a report titled: South Africa’s mineral resource availability as a driver for transitioning to a Circular Economy.
The study was funded by the Department of Science and Innovation through the Waste Research Development and Innovation (RDI) Roadmap Implementation Unit hosted by the Council for Scientific and Industrial Research (CSIR).
Methodology
A desktop study was undertaken to understand the relevance of a CE in the mining sector, after which a briefing note titled: Placing the South African mining sector in the context of a circular economy transition, was published. The briefing note was used to initiate discussions with stakeholders on CE opportunities within the mining sector.
Table 1
This was followed by a literature review, and the gathering of qualitative data through survey questionnaires, unstructured interviews with subject matter experts, and workshops with key stakeholders. Stakeholder engagements were conducted through two workshops and interviews between January 2022 and February 2022. The stakeholder groups for the first workshop included geologists, mining engineers, mineral economists, and mineral resource management practitioners. The stakeholder groups for the second workshop included environmental management practitioners, professionals involved in issues related to sustainability, environmental, social, and governance (ESG), and materials stewardship.
The information solicited enabled the project team to determine the CE opportunities as well as the associated challenges for the mining sector.
CE opportunities for the mining sector
Based on the study undertaken, some of the CE opportunities in the mining sector have been identified and categorised according to the three CE principles.
Table 1 presents a summary of the CE opportunities in the mining sector.
Summary of circular economy opportunities in the mining sector
CE principle
i. Design out waste and pollution.
ii. Keep products and materials in use.
iii. Regenerate natural systems.
CE opportunities in the mining sector
• Increased ore extraction efficiency and precision.
• Water recovery and recycling.
• Substitution of raw materials.
• Technology and waste utilisation for carbon capture.
• Biotechnology or biomimicry.
• Reusing, reducing, and recycling of waste.
• Processing of residues and secondary metals.
• Re-mining of tailings and waste.
• Zero waste-to-landfil strategies.
• Urban mining of electronic waste (e-waste).
• Integration of renewable energy in mining operations.
• Green hydrogen generation.
• Repurposing of post-mining landscapes.
• Eradication of alien invasive plants for water reutilisation.
Figure 1—Mining and metals in a circular economy (ICMM, 2023)
A review of circular economy opportunities in the mining sector
The CE opportunities for the mining sector are discussed in the following subsections.
Design out waste and pollution
Increased ore extraction efficiency and precision
The generation of waste and pollution could be minimised through the development of technologies that could enhance precision and efficiency of ore extraction, with minimal energy usage, reduced water, and capital intensity. Examples of these processes include coarse particle recovery, bulk sorting, ultrafine recovery, fracking, and in situ mining (Anglo American, n.d.).
Kumba Iron Ore, on their journey to sustainable mining, implemented the ultra-high dense medium separation technology, which improved their beneficiation by essentially converting their previous ‘waste’ into ore. The technology also extended Sishen mine’s life from 12 years to 19 years (Creamer, 2021). The Minerals Council South Africa (2019), suggested that modernisation of the mining sector could enable viable extraction of lower-grade orebodies and deeper resources, which cannot be economically mined using current technologies. Modernisation of the mining industry presents an opportunity to reduce the sterilisation of mineral resources, ensuring that the sector derives maximum benefit from the mineral commodities. Thus, modernisation will extend the life of mines (minimise premature mine closures) and enable the development of new low-grade deposit operations. This will subsequently preserve jobs and create new employment opportunities in the mining sector.
Other ways to increase efficiency and precision is to address current issues such as poor fragmentation and excessive ore dilution due to poor drilling and blasting (Pysmenniy et al., 2020). Efficient ore extraction could potentially extend the life of mining operations and increase the range of mineral recovery. This could reduce the environmental footprint as the need to develop greenfield mines will decrease.
Water recovery and recycling
Water scarcity and poor water quality is a major crisis in South Africa (SA), resulting from overexploitation of water resources, lack of infrastructure maintenance, ineffective water resource management, and climate change, which consequently impacts food production (Donnenfeld et al.; 2018; National Planning Commission, 2012). To improve the ecological system, dependence of the mining sector on fresh water sources should be reduced and uptake of water recovery and recycling processes should increase. Possible innovative technologies for water recovery and recycling include dry processing, evaporation management, novel leaching, and dry stacking (Anglo American, n.d.). Implementation of these technologies could enable mines to transition from wet tailings storage facilities, which pose serious failure hazards, to dry stacked tailings, thereby creating stable and sustainable land.
Substitution of raw materials
Substitution of raw materials, where possible, could potentially minimise the overall production of waste and reduce carbon emissions from excessive mining operations. An example is the use of thiosulphate leaching as an alternative to cyanide in gold processing (SGS Mineral Services, 2008).
The European Commission has developed a raw materials commitment, which seeks to identify and develop sustainable substitutes for critical raw materials (CRM) in various industries, including mining (European Commission, 2019). This suggests
that substitution of raw materials could assist in meeting the global demand for CRM for development of clean energy technologies.
Utilisation of captured carbon for value-added products
With the advancements in carbon capture technologies, there is potential to convert carbon dioxide (CO2) into value-added products. These products include clean fuels and chemicals such as methanol, formic acid, and acetal through thermocatalytic, electrochemical, photocatalytic, microbial, and enzymatic methods. Other industrial applications of CO2 from carbon capture are the production of organic carbonates and polycarbonates, which are used in lithium-ion batteries and pharmaceuticals, and conversion of CO2 into supercritical fluids, which are beneficial in chemical processes (Podder et al., 2023).
Biotechnology or biomimicry
Biotechnology may be used to tackle e-waste, which is one of the fastest growing categories of waste (Xavier et al., 2021), e.g., by recovering metals from appliances, cellphones, etc.
Biohydrometallurgical processes are the most feasible for urban biomining and include methods such as bioleaching, bio-oxidation, and biosorption (Xavier et al., 2021).
Kumba Iron Ore’s zero waste-to-landfil strategy incorporates bioremediation of hydrocarbon contaminated soils using bacteria. The bioremediated soil can then be used for rehabilitation of land, instead of being disposed as hazardous material in landfill sites. From the data gathered, it was also found that biomimicry should be considered as a sustainable solution for managing waste as there is a fungus or a bacterium for any type of man-made pollution. It has not really been explored to the extent that is possible or that we should. They are nature’s solutions.
Minerals and metals such as nickel can also be extracted using plants that have been enhanced through synthetic biological processes specifically for this function. The plants are grown in nickel-rich soil and then harvested, following which the metal is recovered from the biomass. This process enables the extraction of minerals in soil below traditional cut-off grades (Genomines, 2022). This innovative extraction process could potentially contribute to closing the supply gap for critical raw materials by using more sustainable and environment-friendly methods of mineral extraction.
Keep products and materials in use
The keep materials in use principle has widely been adopted across the South African mining industry. The interventions under this principle include reducing, reusing, and the recycling of various waste streams, including end-of-life equipment. Some of the CE opportunities under this principle are briefly discussed in the section that follows here.
Zero waste-to-landfill strategies
The zero waste-to-landfill strategy is a waste management approach, which aims to divert at least 99 per cent (99%) of all waste generated at a particular business away from landfils (Carbon Trust, 2017; Intertek, n.d.). This implies that all waste that is produced will be either reused, recycled, composted, or sent to energy recovery.
As reported in their 2020 sustainability report, Anglo American’s Kumba Iron Ore adopted the zero-waste-to-landfil strategy that was aimed at eradicating waste disposal in landfills (Anglo American, 2020).
A review of circular economy opportunities in the mining sector
Reuse/repurposing of mine waste
CE interventions under the reuse and repurposing of mine waste principle include (Lottermoser, 2011; ICMM, 2016):
➤ Repurposing waste rock for several uses such as reprocessing to extract remnants of valuable minerals, buttressing of highwalls, landscaping, aggregates for construction, raw material for cement manufacturing, and backfilling minedout areas.
➤ Using manganese tailings for producing resin, glass, construction materials and coatings, and in agroforestry.
➤ Using clay-rich tailings for bricks, cement, and floor tiles manufacturing.
➤ Utilising slag in road construction, and cement and concrete production.
➤ Repurposing bauxite red mud for soil and wastewater treatment, and as a raw material for ceramics, glass, and brick manufacturing.
➤ Reusing mine water for several purposes such as cooling, source of drinking water, dust suppression, and mineral processing, and for other agricultural and industrial applications.
➤ Making pigments using iron-rich sludge from acid rock drainage treatment.
➤ The repurposing of old tyres is another CE opportunity, which has been adopted by some mines locally and globally. Thermal conversation/pyrolysis of tyres (a process in which the organic material in tyres is decomposed with heat in the absence of oxygen, thus converting the tyres back into their original components, namely fuel oil, carbon black, and steel) could potentially provide a sustainable solution for recycling large tyres towards a circular economy (Kal Tire, 2023). For example, a 63-inch diameter radial tyre could be broken down using thermal conversion/pyrolysis to produce approximately 1600 kg of carbon ash, 900 kg of high tensile steel, 2000 litres of petroleum-based products, and 350 cubic metres of synthetic gas (Figure 2). The carbon ash can be used as a replacement for new carbon black, while the petroleumbased products can be used to create new tyres and the synthetic gas that is used to feed the recycling process (Kal Tire, 2023).
Re-mining of tailings
Mining companies are leveraging on technological developments and innovations to re-mine tailings. Re-mining of tailings gives the mining industry an opportunity to convert legacy mining-related liabilities into opportunities, which can create alternative economic
and employment opportunities. For example, Sibanye-Stillwater successfully implemented the West Rand Tailings Retreatment Project (WRTRP), resulting in the realisation of some shared benefits to all key stakeholders (Sibanye Gold, 2016). Other South African mining companies involved in re-mining of gold waste rock dumps include DRDGOLD, Mintail, and Goldfields.
Recycling metals and processing of residues and secondary metals
Under this initiative, new scrap is directly remelted to new metal or melted and refined to pure metal or alloys with limited oxidation and reduction, while old scrap and metal containing wastes or residues are usually refined via pyro-, hydro-, and electrometallurgical techniques.The aluminium industry is embracing the recycling of scrap metal, which was accelerated by the COVID-19 pandemic-related logistics challenges associated with bauxite imports. Aluminium is a potential ‘green’ metal that can be recycled several times without losing its original properties (European Aluminium, n.d.).
Besides the efforts aimed at reducing waste generated from mineral processing-related activities, additional CE opportunities can be harnessed from the processing of secondary metals and residues. Practical CE opportunities under this thrust area include (ICMM, 2016):
➤ Producing metals using scrap in combination with primary concentrates.
➤ Producing valuable metals such as gold, silver, copper, and palladium from secondary smelting of electronic scrap.
➤ Enhancing the recovery of coproducts from mining activities. For example, a nickel mining company can opimise the recovery of coproducts such as copper, platinum-group metals (PGM), and cobalt.
➤ Decreasing the volume of acid gases emitted into the natural environment by interventions such as producing sulphuric acid using the off-gas cleaning process in primary smelters.
➤ Converting sulphur dioxide to sulphuric acid through processes such as the incorporation of acid plants into the smelting process.
Urban mining of e-waste
There is an opportunity for existing mining companies to create alternative business models and employment opportunities through the recovery of end-of-life products and/or e-waste (urban mining). Mining companies can create subsidiary companies that recover and reprocess scrap metal. It was reported that since 2018, less than 10% of e-waste was collected for recycling in SA and most of the e-waste was exported and processed internationally. It is noteworthy that the University of Cape Town commissioned a research project aimed at developing technologies to recover and process copper and gold from circuit boards in SA. The project will also investigate the feasibility of using the chemical extraction process for copper using ammonium sulphate (Eco Africa, 2021).
Regenerate natural systems
Renewable energy
The integration of renewable energy such as solar, wind, and hydrogen (green energy) to power mining operations will reduce energy consumption, costs, and carbon footprint. Gold Field’s South Deep mine near Westonaria constructed its 50MW Khanyisa solar plant to partially mitigate the impacts of Eskom’s unreliable supply
Figure 2—Thermal conversion/pyrolysis of large tyres (Kal Tire, 2023)
A review of circular economy opportunities in the mining sector
(Gold Fields, 2022). Gold Fields (2022) reported that the solar plant saves 24% of their electricity costs and can also significantly reduce their carbon emissions.
Green hydrogen generation
Green hydrogen production has huge economic potential for SA, which would consequently result in increasing demands for PGMplatinum is used as a catalyst in fuel cells (Hinkly, 2021).
The advent of hydrogen production may allude to the adoption of fuel cell technologies in the country. Fuel cells are used in electric vehicles (EV). Mining companies such as Anglo American and Impala Platinum have already adopted the use of fuel cell electric vehicles (FCEV) at South African mining operations. The Paris Agreement binds SA to strive for zero carbon power (hydrogen, solar, and wind). The production of green hydrogen requires renewable energy (solar and wind power), both of which are abundant in SA. This positions SA favourably and has potential for its economy in the future - decarbonisation of its local economy and exporter of green energy (PwC, n.d.).
Repurposing of post-mining landscapes
Old mine sites could potentially be rehabilitated and repurposed as educational training centres, agricultural land (e.g., wheat pilot project in Mpumalanga), or tourist attractions (e.g., museums or theme parks). Examples of old mines repurposed as tourist attractions is Gold Reef City in Johannesburg and The Big Hole in Kimberly.
Eradication of alien invasive plants for water reutilisation
SA’s Working for Water (WfW) programme aims to accelerate the eradication of invasive biomass. It is said that 2.9% to 6% of water is captured by alien invasive plants – when removed, water may be released for other uses (Department of Forestry, Fisheries and the Environment, 2022). For mines, this water may significantly benefit the company and the communities if the invasives were to be cleared around the mines. It may also provide the opportunity to use natural, regenerative systems to treat mine waters, e.g., natural wetland systems, which contribute to local ecosystem services.
Challenges to the implementation of circular practices
The study found that several CE opportunities are available and already being implemented in a silo fashion across the industry. However, the holistic and sustainable adoption of circularity across the mining sector continues to face several challenges. Huge volumes of waste rock and tailings are generated from mining activities. However, the current rate of reuse and repurposing is much lower than the rate at which the waste is generated.
Anglo American (2020), reported that their zero-wasteto-landfill strategy faced a challenge in the segregation of nonhazardous waste because not all waste streams could be recycled due to technological constraints. There is a general lack of sustainable solutions to recycle large tyres, which are difficult to handle and manage. Anglo American (2020) further noted that Kumba Iron Ore stored about 20 000 tonnes of scrap tyres in 2020 and the company was still exploring circular economy solutions for the management of large waste tyres.
The study revealed that although some of the aforementioned CE interventions are economically viable; they are not always operationally feasible to implement. For example, backfilling of mined-out areas using waste rock could be difficult to implement in surface mines practicing selective mining and blending of ore from different areas within the pit at different times, in order to
meet the required quantities and quality of ore. There is a need for collaborative research, development, and innovation (RDI) to develop innovative and implementable CE interventions to address these waste management challenges.
The research established that although pockets of CE interventions have been adopted across the mining sector, the adoption has not been done holistically and, at a large scale, results in marginal realisation of the socio-economic and environmental benefits. It is envisaged that a holistic adoption and large-scale implementation of CE interventions across the mining sector could offer the industry an opportunity to convert legacy waste management issues into significant socio-economic opportunities.
ACEA (2018) argued that the large-scale roll-out of CE solutions in the mining sector could be inhibited by huge investment requirements associated with the interventions. The study found that sustainable circularisation of the mining industry requires a collaborative approach among all key stakeholders and the process should be underpinned by customised incentives and legislative framework.
Moreover, the research revealed that sustainable implementation of longer-term CE opportunities such as urban mining of e-waste could be hindered by difficulties related to hazardous e-waste characterisation. Thus, there is a need for further RDI to develop solutions to some of these challenges.
Conclusion and recommendations
The most implementable CE opportunities in the mining sector are those aligned with the keep materials in use principle and many mining companies are already implementing practices aligned with this second principle. These include reducing, reusing and recycling of materials. Although some of the opportunities mentioned within this category are not new concepts, challenges still remain when it comes to the implementation of these initiatives. The challenges are mainly operational and financial, suggesting that RDI are key focus areas to addressing these issues.
The high impact opportunities aligned with the first principle of designing out waste and pollution and the third principle of regenerating natural systems are more difficult to implement, as they require large investments.
In terms of financial constraints to implementation, the cost versus long-term benefit of these interventions needs to be studied and realised. Even though some mining companies adopt CE principles, the interventions need to be scaled up to make a meaningful impact on the business, society, environment, and the economy at large.
Acknowledgements
We would like to thank the Department of Science and Innovation for funding this project, through the Waste Research Development and Innovation Roadmap Implementation Unit hosted by the Council for Scientific and Industrial Research. We would like to acknowledge Professor Linda Godfrey, Manager of the Waste Research Development and Innovation Roadmap Implementation Unit, for her guidance. We also thank all the South African mining industry stakeholders for their participation in this research.
A review of circular economy opportunities in the mining sector
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Affiliation:
1Faculty of Law, North-West University, South Africa
2Oliver Schreiner School of Law, University of Witwatersrand, South Africa
Correspondence to: F. Agyemang
Email: 29763959@mynwu.ac.za
Dates:
Received: 6 May 2025
Revised: 23 Nov. 2025
Accepted: 2 Dec. 2025
Published: December 2025
How to cite:
Agyemang, F., Ashukem, J.C.N. 2025. Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 725–736
DOI ID:
https://doi.org/10.17159/2411-9717/3723/2025
ORCiD:
F. Agyemang
http://orcid.org/0000-0002-3688-2944
J.C.N. Ashukem
https://orcid.org.0000-0003-1993-6258
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
by F. Agyemang1, J.C.N. Ashukem2
Abstract
One understudied area of environmental law is the socio-ecological impact of ownerless mines. This impact is particularly pronounced in resource-dependent regions like South Africa and Western Australia, creating significant rehabilitation challenges. This article hypothesises that effectively managed financial provision could be valuable for rehabilitating legacy mines.
Using a qualitative, comparative methodology, the article analyses the financial provisions for mine rehabilitation in South Africa and Western Australia, focusing on statutory provisions, funding mechanisms, and rehabilitation outcomes. Key themes, such as context, measures, and outcomes, are explored to assess the effectiveness of each financial model. Purposive sampling is used to select case studies from both regions, and thematic analysis is applied to interpret the data.
The analysis highlights the financial rehabilitation measures in both regions, providing a structured framework for ownerless mine rehabilitation. South Africa's approach, guided by the Mineral and Petroleum Resources Development Act (MPRDA) of 2002, depends on state budget allocations, leading to funding inconsistencies and slow rehabilitation progress. In contrast, Western Australia’s Mine Rehabilitation Fund Act (MRFA) of 2012 uses a levy-based system, ensuring continuous financial support for mine rehabilitation.
South Africa's state-dependent model has led to delays in rehabilitating derelict and ownerless mines, while Western Australia’s funding model has facilitated steady progress. The article recommends that South Africa adopt a levy-based financial mechanism, strengthen legislative enforcement, improve financial oversight, and integrate proactive mine closure strategies to accelerate rehabilitation, reduce environmental hazards, and promote sustainable development in mining-affected communities.
Keywords
South Africa, Western Australia, legacy mine, mine rehabilitation, financial provision
Introduction
Mine rehabilitation is a central pillar of sustainable mining governance, ensuring that environmental harm caused by extraction is effectively remediated and that degraded landscapes are restored for future use (Joseph, 2025). Yet, despite its clear socio-ecological benefits, rehabilitation remains one of the most persistent regulatory challenges in resource-dependent jurisdictions such as South Africa and Western Australia. The most acute difficulty concerns legacy or abandoned mines, which continue to generate severe and long-lasting environmental and public health impacts. These sites commonly require state intervention, raising questions about whether statutory financial mechanisms can provide a reliable and effective basis for long-term rehabilitation. Financial provisioning, funds that mining right holders must secure in advance for closure, rehabilitation, and water treatment, is intended precisely to prevent environmental liabilities from shifting to the state.
Historically, however, mining operations in both jurisdictions were frequently abandoned without reclamation obligations, leaving behind hazardous pits, tailings, contaminated soils, altered hydrological systems, and land instability. The scale of the resulting legacy is substantial: South Africa has approximately 6,100 derelict and ownerless mines (Auditor-General South Africa, 2021), while Australia has around 60,000 abandoned sites dating to the 1800s, including more than 138,000 hectares in Western Australia alone, of which only 39,674 hectares have been rehabilitated (Callari, 2020). Because many original operators no longer exist, cannot be traced, or lack financial capacity, accountability gaps are pervasive (Feris, Kotzé, 2014). Government-led rehabilitation is also constrained by limited budgets and
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
capacity, resulting in thousands of sites continuing to pollute the environment for decades (Fowler-Puja, Barbanell, 2025).
Empirical data underscore the magnitude of the challenge. In South Africa, rehabilitating five abandoned mines cost R42 million (Auditor-General South Africa, 2009), and the remaining 229 alone are projected to require R3.86 billion by 2033 (Auditor-General South Africa, 2021). South Africa’s legal framework embeds the polluter-pays principle, reflected in section 28 and section 24R(1) of the National Environmental Management Act (NEMA) 107 of 1998, and expressly provides that environmental costs should not be shifted to communities, as articulated in the White Paper on Environmental Management Policy for South Africa (Republic of South Africa, 1998a). However, an effective liability regime presupposes identifiable and solvent operators, conditions generally absent in the context of legacy mines. Section 46 of the Mineral and Petroleum Resources Development Act (MPRDA) 28 of 2002 (Republic of South Africa, 2002) accordingly obliges the state to rehabilitate mines where the operator is deceased, untraceable, or dissolved. Parliament has also proposed introducing an environmental levy on operating mines to offset rehabilitation costs (Department of Water and Sanitation & Chamber of Mines, 2014), raising concerns that the financial burden may ultimately fall on taxpayers (Lombard, 2018).
In contrast, Western Australia’s Mine Rehabilitation Fund Act (MRFA) of 2012 establishes a dedicated, industry-funded pooled levy that provides stable, long-term financing for abandoned and legacy sites while limiting fiscal risk to the state (Government of Western Australia, 2021). Although Klopper and Wessels (2017) recommend adopting Western Australia’s pooled fund approach in South Africa, their analysis does not fully interrogate key components of financial rehabilitation, such as levy design, fund sustainability, long-term liability coverage, and actual rehabilitation performance. This article advances the debate by offering a deeper comparative assessment of the two financing models, drawing on audit data, policy instruments, and institutional performance. Against this backdrop, the paper first reviews the conceptual and empirical literature on legacy mines and their socio-economic and environmental impacts. Second, it outlines the regulatory frameworks of the two jurisdictions and evaluates the structure and performance of South Africa’s and Western Australia’s financial rehabilitation systems, identifying the core strengths, weaknesses, and governance implications of each. Third, it describes the research methodology. The fourth section presents the comparative findings and distils key lessons for reform. Section five discusses the policy implications, and the final section offers recommendations and a conclusion.
Literature review
Overview of legacy mines
A legacy site refers to a former mining area where the rights or titles have expired, leaving no party accountable for rehabilitation (Oberle et al., 2020). Such sites often comprise abandoned or orphaned mines and residual waste facilities. The term ‘orphaned’ is employed when no owner can be identified, while ‘abandoned’ applies when the owner is known but lacks the financial means or willingness to undertake rehabilitation work (Oberle et al., 2020). Derelict and ownerless mines are those that have ceased operations, lack safety management and maintenance, and for which the owners, as defined by the MPRDA (section 56), have abandoned the mine and cannot be traced (Auditor-General South Africa, 2021). The government of Western Australia defines abandoned mine sites as
areas affected by former mining activities for which no individual, company, or organisation can be held accountable for rehabilitation (Bennett, Kim, 2016). According to Fowler-Puja and Barbanell (2025), the Good Samaritan Remediation of Abandoned Hardrock Mines Act of 2024 introduces a new legal definition for abandoned mines, classifying them as sites deserted before 11 December 1980. In this article, the terms legacy mines and historically abandoned mines are used interchangeably to refer to mine sites that were closed or ceased operations before the enactment of key mining rehabilitation legislation, such as the MPRDA and NEMA of South Africa. Consequently, the responsibility for their rehabilitation now rests with the government.
Derelict and ownerless mines have significant environmental impacts. These include acid mine drainage (AMD) and toxic metal leaching, which contaminate soil and water sources degrades stream quality and leads to biodiversity loss (McCarthy, 2011). To address this issue, the Department of Water and Sanitation established three AMD treatment plants in the Witwatersrand Basin by 2016, investing R2.59 billion to treat contaminated water and manage waste (Auditor-General South Africa, 2021). Unrehabilitated postmining landscapes also harm air quality by releasing hazardous dust that affects ecosystems and human health (Bennett, 2016). Mine dust is associated with respiratory diseases, lung cancer, and other illnesses, particularly among vulnerable groups. Communities near abandoned asbestos dumps face ongoing exposure to fibres that cause asbestosis, lung cancer, and mesothelioma, a disease with the highest global incidence rate in South Africa (Auditor-General South Africa, 2021). Radioactive uranium from gold mining further contaminates ecosystems, leading to genetic mutations and cancers. Coal dumps, prone to spontaneous fires, emit sulphur, mercury, and arsenic, further degrading air quality and endangering nearby communities. Mine dust also diminishes soil quality, hindering vegetation growth (Auditor-General South Africa, 2021). Another critical environmental concern is land subsidence caused by collapsing underground mines, which pollutes water sources, threatens human safety, damages infrastructure, and permanently alters landscapes (Auditor-General South Africa, 2021).
Beyond environmental concerns, a significant social issue associated with legacy mines in South Africa is the rise of illegal small-scale mining, commonly known as Zama-Zama activities (Ledwaba, Nhlengetwa, 2016). These illicit mining practices, including hand-dug and mechanised excavations, often destabilise old shafts and excavated cavities, increasing the risk of collapse, especially after heavy rainfall. The consequences of such activities are extensive, with profound social and economic implications for the government, the mining sector, and society at large. Furthermore, illegal mining undermines the effectiveness of the government's shaft-sealing programme, as previously closed shafts are frequently reopened (Auditor-General South Africa, 2021). Notably, the South African government has spent over R49 billion in efforts to combat illegal mining (Hlati, 2024).
A pressing concern is the loss of agricultural land and livelihoods, as mining companies frequently neglect to restore mined areas once leases expire or resources are depleted (Ocansey, 2013). This loss of land disproportionately affects vulnerable groups, particularly those whose access to land and rights are disrupted (Vermeulen, Cotula, 2013). Mining-induced land dispossession extends beyond the loss of farmland to include the erosion of access to shared resources such as forests (utilised for firewood, hunting, and medicinal plants), grazing areas, fishing zones, and pathways that connect farmers to water sources for irrigation (Amponsah et
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
al., 2021). Oxfam Australia (2024) indicates that large-scale mining projects frequently result in the displacement of local communities, often necessitating their resettlement in unfamiliar areas. While it is incumbent upon governments and developers to safeguard the welfare of resettled communities, these procedures are frequently involuntary and inadequately managed, leading to heightened vulnerability and increased impoverishment. Resettlement may precipitate the loss of livelihoods and limit access to vital resources such as food and water. In instances where resettlement programmes are poorly designed or executed, affected families may encounter substantial challenges in resuming agricultural practices or identifying alternative income sources. Furthermore, resettlement locations are often remote, situated at considerable distances from urban centres, markets, and critical services, thereby exacerbating the hardships encountered by displaced communities (Oxfam Australia, 2024).
Legacy mines in South Africa largely stem from over 120 years of gold mining in the Witwatersrand Basin, according to the Commission for Human Rights, a region historically responsible for approximately one-third of global gold production. In rural South Africa, where mining typically occurs under customary land tenure, abandoned mines raise serious concerns about intergenerational equity. Land that has been passed down through generations may become permanently inaccessible, thereby undermining the potential for future generations to maintain their livelihoods. As Weiss (1992) notes:
We look at the earth and its resources not only as an investment opportunity but as a trust passed to us by our ancestors for our benefit and to be preserved for future generations.
The aforementioned highlights the need to view land as an intergenerational asset with cultural, economic, and environmental implications that extend well beyond the present (Amponsah et al., 2021).
Financial rehabilitation models of legacy mines
South African model
Financial rehabilitation measures
In South Africa, mining is regulated by an extensive legal and policy framework centred on the Constitution of the Republic of South Africa (1996), the NEMA, and the MPRDA, among other statutes. The Constitution, as the supreme law (s 2), provides the foundational normative framework for all environmental and mining legislation. Section 24 guarantees everyone the right to an environment that is not harmful to health or well-being and obliges the state to enact reasonable measures to prevent environmental degradation. Although mine rehabilitation is not expressly mentioned, the severe socio-ecological risks posed by abandoned mines fall squarely within the protective mandate of section 24, thereby creating a strong constitutional justification for state- and industry-led rehabilitation interventions.
The NEMA operationalises the environmental right through a comprehensive suite of regulatory obligations relevant to mining rehabilitation. Section 24P requires mining operators to make adequate and annually reviewed financial provision for rehabilitation, verified through independent audits and secured through approved financial instruments such as trust funds or guarantees. Sections 24 and 24P, therefore, function together to ensure that environmental authorisations impose enforceable rehabilitation conditions backed by secured financial resources.
Additionally, section 28 introduces a broad duty of care requiring any person who causes, has caused, or may cause environmental degradation to take reasonable remedial measures, including addressing latent or residual impacts. Section 24 further prohibits listed activities without prior environmental authorisation, typically supported by an environmental impact assessment (EIA) and an Environmental Management Programme (EMP), which collectively guide rehabilitation and long-term monitoring responsibilities.
The MPRDA, which governs the granting of prospecting and mining rights, reinforces these obligations through a parallel set of financial mechanisms. While the Act does not explicitly codify a general rehabilitation obligation, section 41(1) requires applicants for prospecting rights, mining rights or permits to provide financial provision for environmental rehabilitation before approval of their environmental management plan. Section 42(2) authorises the Minister to utilise these funds where a mining operator fails to meet rehabilitation obligations. Section 46(1) further empowers the Minister to intervene directly to remedy environmental harm, particularly where the responsible party is untraceable, deceased, or in liquidation. Where no responsible party exists, section 45 assigns the state residual responsibility for rehabilitation.
This framework must be read in light of the principle of legality, including the prohibition on retroactive imposition of criminal or civil liability. The doctrines of nullum crimen sine lege (no crime without law) and the general non-retrospectivity of legal obligations ensure that individuals and entities cannot be punished or burdened for conduct that was lawful at the time it occurred (Binder, 2002; Johnston, 1996). As Hart and Green (2012) emphasise, laws must be prospective, clear, and accessible. Echoing Dicey’s classical formulation: “no man is punishable… except for a distinct breach of law established in the ordinary legal manner” (Lawteacher.net, 2024). Against this backdrop, section 46(1) of the MPRDA appears normatively coherent: it allows state intervention where no prior legal obligation required the operator to rehabilitate. At the same time, however, the provision raises tensions with the polluterpays principle, which holds that those who cause pollution should bear its costs (Kenehan, 2022), and with the broader duty of care principle requiring reasonable preventive measures (Australian Government Department of Health and Aged Care, 2023). It also conflicts with the White Paper on Minerals and Mining Policy for South Africa (1998a), which unequivocally states that environmental costs should not be shifted to the public.
Rehabilitation liability in South Africa is quantified under section 24P of NEMA and the Financial Provisioning Regulations, 2015 (GN R1147). These regulations require mining companies to secure the full cost of environmental rehabilitation across three components. First, progressive rehabilitation entails annual, sitespecific costs related to reshaping, stabilisation, and revegetation, as required under Regulation 6(a). Second, decommissioning and closure obligations cover demolition, soil remediation, and landform stabilisation, costing on the assumption that work is undertaken by an independent contractor in accordance with Regulation 6(b) (2015). Third, latent and residual impacts include long-term liabilities such as acid mine drainage, water treatment, and post-closure monitoring, calculated using longterm projections and present-value methodologies in line with Regulation 6(c) (Department of Environmental Affairs, 2015). The sum of these components forms the total financial provision, which must be secured through authorised instruments, including bank guarantees, insurance products, or rehabilitation trusts (Regulations 8–10) (DEA 2015).
Comparative
Observed performance outcomes
The Auditor-General reports indicate that 2,908 of the identified DOMs do not require rehabilitation. In 2010, the government planned to repair approximately 2,000 DOMs by 2021 because of their significant dangers and far-reaching consequences for society and the environment. The goal was to rehabilitate 6,100 DOMs by 2038 (Auditor-General South Africa, 2021). However, as of 31 March 2021, there has been relatively limited progress. Apart from asbestos mines, none of the 2,322 high-risk commodity DOMs had undergone rehabilitation (Auditor-General South Africa, 2021). Among the 1,170 identified holings, 507 (43%) were recorded as closed in the DOMs database. Of the 261 asbestos mines, only 32 (12%) had been rehabilitated since the programme’s launch in 2006–2007, with the remaining 229 mines earmarked for rehabilitation by 2033 (Auditor-General South Africa, 2021). Generally, rehabilitation efforts in South Africa have shown modest progress over the past 12 years (31 March 2010–31 March 2021), with the average annual percentage of rehabilitated mines increasing from 1.67% in 2009 to 2.25% in 2021 (Auditor-General South Africa, 2021).
Figure 1 provides an overview of mining rehabilitation progress in South Africa as of 31 March 2021, serving as a valuable tool for stakeholders to monitor, evaluate, and improve their efforts towards environmental sustainability in the mining sector. The sectors are asbestos, holings, and high-risk commodity mines. Rehabilitation progress is further categorised into three groups: sites not rehabilitated or closed (depicted in dark blue), sites rehabilitated between 2009 and 2021 (orange), and those rehabilitated up to 2009 (green). For asbestos sites, a total of 261 sites is recorded, of which 229 (88%) remain unrehabilitated, 27 (10%) were rehabilitated between 2009 and 2021, and only 5 (2%) were rehabilitated before 2009. This indicates a slow pace of progress, with the vast majority still requiring attention. In the holings sector, out of 1,170 sites, 663 (57%) remain unrehabilitated, while 507 (43%) have been rehabilitated between 2009 and 2021, reflecting comparatively better performance than asbestos sites, though over half still await rehabilitation. The most alarming section is that of high risk commodity mines, comprising 2,322 sites, all of which remain unrehabilitated, with no progress reported either before 2009 or between 2009 and 2021. This points to a complete lack of action in addressing these particularly hazardous sites. This lack of progress in the high-risk commodity mines underscores an urgent need for targeted funding, enhanced policy enforcement, and accelerated
implementation of rehabilitation programmes to safeguard public health and mitigate long-term environmental damage.
Since the inception of the rehabilitation programme in 2010, the National Treasury has failed to provide adequate annual funding to ensure the complete rehabilitation of all DOMs by 2038 (AuditorGeneral South Africa, 2021). This failure is concerning, given that the funding allocated through the Medium-Term Expenditure Framework (MTEF) was primarily directed toward rehabilitating DOAMs and the holings programme, without considering the budget required for the remaining 2,322 high-risk commodity DOMs (Auditor-General South Africa, 2021). The 2021 valuation report revealed a rehabilitation cost of roughly R3,860,741,741 for the remaining 229 DOAMs by 31 March 2033. However, the current funding level would only allocate 44% of this amount (R1,696,528,316) to the asbestos rehabilitation programme by that date. Hence, the necessary funding to complete the rehabilitation of the remaining 229 DOAMs would not be accessible until 2043 (Auditor-General South Africa, 2021). In parallel to the issue of insufficient funding, the timeline for rehabilitating the remaining 229 DOAMs do not reflect the actual pace at which the Council for Mineral Technology (Mintek), the department's executing agent for asbestos rehabilitation, plans and implements these projects (Auditor-General South Africa, 2021). This reveals a profound implementation gap, underscoring a persistent disconnect between planning and execution. The contrast between projected timelines and actual progress illustrates chronic underfunding, weak institutional capacity, and an evident lack of urgency. Without decisive intervention, the remaining asbestos sites will continue to pose serious environmental and public health risks for decades. This makes it imperative to strengthen funding mechanisms, accelerate implementation, and adopt more efficient rehabilitation strategies to protect affected communities. Equally troubling is the apparent lack of political will by the minister and the state to address mining impacts in line with the constitutional right to an environment not harmful to health or well-being, as stipulated in section 24 of the South African Constitution (Republic of South Africa, 1996). This aligns with broader observations that, despite South Africa’s sophisticated environmental governance framework, implementation, not legislation, is the primary obstacle. As Ashukem (2024) cautions, laws do not implement themselves. Effective enforcement and administrative commitment are therefore essential if rehabilitation obligations are to translate into tangible environmental outcomes.
Figure 1—Rehabilitation progress on 31 March 2021 — Source: Auditor-General South Africa (2021)
Comparative
Source: Auditor-General South Africa
Figure 2 highlights the discrepancy between the projected and actual completion timelines for rehabilitating the remaining 229 DOAMs, considering funding allocation levels and operational implementation plans. Among the key elements, the Valuation Report Target Date (2033) stands as the most optimistic estimate, reflecting the early planning milestone aimed at assessing the scope and cost of rehabilitation. The Annual Budget Allocation (2043) projects completion based on current funding trends, suggesting a delay from the valuation target and revealing potential limitations in resource mobilisation. The Mintek Three-Year Cycle Implementation Plan (2090) extends the timeline considerably, likely due to a phased implementation strategy that rolls out the rehabilitation in cycles, indicating slow progress. Most concerning is the Actual Rate (2132), which shows that if the current pace continues, full rehabilitation will not be achieved until more than a century from now.
Western Australia model
Financial
rehabilitation measures
In Western Australia, mining activities are regulated by various laws and policies, including the Constitution of the Commonwealth of Australia (CACA) 1900, the Environment Protection and Biodiversity Conservation Act (EPBCA) 1999, the Mining Act (MA) 1978, and the Environmental Protection Act (EPA) 1986. The EPBCA mandates EIA for significant projects, including mining, to assess potential impacts on matters of national environmental significance, such as threatened species and world heritage properties (1999 (Cth), s 18). Section 18 regulates actions likely to significantly affect these protected areas.
The MA governs mining activities in Western Australia, including the granting of mining leases and ensuring compliance with environmental laws. Section 58 of the Act outlines the requirements for granting mining leases, while section 82 of the Act mandates the rehabilitation of land after mining activities, although no dedicated funding scheme is provided (Mining Act 1978 (Western Australia) (WA), ss 58, 82). The EPA establishes the Environmental Protection Authority, which assesses the environmental impacts of mining proposals. Section 48 requires the Environmental Protection Authority to recommend conditions to mitigate adverse effects, but, like the MA, it does not include a formal funding scheme for rehabilitation (Environmental Protection Act 1986 (WA), s 48).
However, the exclusive authority for ensuring financial provisions for mine rehabilitation resides with the MRFA 2012 (WA). The Authority oversees the administration of the Fund and ensures that mining companies fulfil their obligations regarding land restoration as per the MRFA 2012 (WA, ss 6–10). Section 5(1) of the Act creates the Mining Rehabilitation Fund (MRF), a designated account as required under section 16 of the Financial Management Act 2006 (WA), the MRFA 2012 (WA), s 5(1), and the Financial Management Act 2006 (WA), s 16.
The primary purpose of the Fund is to provide financial resources for the rehabilitation of abandoned mine sites and other land adversely affected by mining activities. Under section 8(1) of the Act, monies in the MRF, including investment income, may be used to: (a) support the rehabilitation of (i) abandoned mine sites that were previously subject to mining authorisations with a levy obligation, and (ii) land affected by such sites; and (b) cover refunds required under Part 4 of the Act MRFA 2012 (WA), s 8(1)). In addition, section 8(2) provides that investment income may also be applied for other purposes, including supporting the rehabilitation of abandoned mine sites not covered under subsection 1(a)(i), financing associated affected land rehabilitation, and funding programmes, information dissemination, and administrative and enforcement activities related to rehabilitation efforts (Mining Rehabilitation Fund Act 2012 (WA), s 8(2)).
The levy in Western Australia is calculated using the formula: Levy = RLE × FCR, where the rehabilitation liability estimate (RLE) reflects the notional cost of rehabilitating disturbed land and the fund contribution rate (FCR) is set at 1% under Regulation 4 of the Mining Rehabilitation Fund MRFA Regulations 2013 (WA) (MRF Regulations 2013 (WA), reg 4). To determine the RLE, tenement holders must classify all disturbed areas according to the Schedule 1 disturbance categories, including pits, waste dumps, tailings storage facilities, plant sites, roads, camps, and other infrastructure footprints, each of which carries a standard unit rehabilitation rate (MRF Regulations 2013 (WA), Sch 1). The RLE is calculated by multiplying the hectares in each disturbance category by its corresponding unit rate and summing the results. In terms of Regulation 5(2), if the total RLE is AUD50,000 or less, no levy is payable for that assessment year, thereby exempting very small or low-disturbance operations (MRF Regulations 2013 (WA), reg 5(2)).
Observed performance outcomes
For the financial year 2022–2023, mining rehabilitation levies amounting to AUD42.8 million were assessed based on information
Figure 2—Expected year of completion for the remaining 229 DOAMs across actual, strategic, and operational plans and funding levels (from 1 April 2021)
(2021)
Comparative
legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
submitted up to 15 September 2023, compared to AUD40.1 million reported in the previous 2022 (Government of Western Australia, 2023). This represents a 9.2% increase from the 2021–2022 period (Government of Western Australia, 2023). As of 15 September 2023, 97.5% of these levies had been collected (Government of Western Australia, 2023). As of 30 June 2023, Western Australia's pooled fund had a net balance of AUD291.2 million, including AUD3.1 million in net interest (Government of Western Australia, 2023). The Government of Western Australia (2023) further assert that projects funded by interest, including those targeting legacy mines, focus on mitigating environmental impacts and promoting sustainable mining site management.
According to the Government of Western Australia (2023), examples of legacy mine projects financed through this interest include:
➤ Safer Shafts for Towns (Nyamal, Wajarri Yamatji, YungungaNya, Yamatji Nation): Launched in 2022, this initiative aims to reduce the risk of exposure to abandoned mine shafts, particularly for children. The project follows a staged approach, with plans for expansion to other regional areas as additional funding becomes available.
➤ Donnybrook Shafts (Gnaala Karla Boodja): This project focuses on rehabilitating eleven mine shafts in the state forest, in collaboration with the Department of Biodiversity, Conservation and Attractions (DBCA). The rehabilitation has been completed, and monitoring efforts are ongoing.
➤ Silicate Minerals: Currently under development, this project involves a partnership with Landgate to leverage hyperspectral data in assessing the presence, extent, and density of crocidolite associated with legacy mining operations.
➤ Collieries (Gnaala Karla Boodja): This project aims to compile data and establish a framework for mapping and prioritising areas affected by ground subsidence and carbonaceous shale from legacy underground coal mining.
➤ Northampton Shafts (Yamatji Nation): Following a staged progression, this project supports the Department of Planning, Lands and Heritage (DPLH) Northampton Lead Programmes. Heritage surveys are underway, with geotechnical investigations planned for the next phase.
➤ Legacy Tailings: In development, this project seeks to detect and monitor changes in constructed landforms using nextgeneration satellite synthetic aperture radar (InSAR) data.
Figure 3 presents the levies paid annually (AUD) over ten years. The data reveal a steady upward trend in levy payments, indicating improved compliance, increased levy rates, or economic growth in the sectors being levied. In 2014, the amount paid stood at AUD26.73 million, with slight annual increases until 2017, when it reached AUD28.89 million. A more noticeable rise begins from 2018 onwards, where payments increased to AUD30.33 million, followed by consistent year-on-year growth: AUD32.62 million in 2019, AUD35.5 million in 2020, AUD37.26 million in 2021, and AUD39.79 million in 2022. The peak is observed in 2023, with AUD42.78 million paid, marking a 60% increase from the 2014 figure. This consistent rise suggests strengthened enforcement mechanisms, expanded taxable activities, or broader economic expansion contributing to higher levy collections. The data also points to effective revenue mobilisation strategies over the decade. Overall, there is a positive trajectory in fiscal performance regarding levies, with 2023 being the highest point in the reporting period.
In the financial year 2022–2023, the land area reported as ‘under rehabilitation’ (indicating ongoing rehabilitation efforts) increased by approximately 1,835 hectares to 43,876 hectares, marking a 4.4% rise from the previous year (Government of Western Australia, 2023). During the same period, the area of ‘active’ disturbance expanded by around 10,681 hectares (6.2%) to 182,059 hectares (Government of Western Australia, 2023).
Consequently, land under rehabilitation accounted for 19.6% of all disturbed land (including land undergoing rehabilitation) and 24.1% of the active disturbance area. These findings suggest that while the land area undergoing rehabilitation experienced its most significant increase since 2019–2020, the pace of rehabilitation continues to lag behind the rate of new disturbance (Government of Western Australia, 2023). The reported extent of ‘active’ disturbance in 2022–2023 exceeded the area classified as ‘under rehabilitation’ by more than fourfold, continuing a trend that had steadily risen since 2014–2015, when the ratio stood at 3.1 (Government of Western Australia, 2023).
Research methodology
This article adopts a comparative qualitative case-study design, relying exclusively on secondary sources and desktop-based research. It is not an empirical investigation; rather, it draws on legislation, policy frameworks, and authoritative reports, including those of the Auditor-General of South Africa and the Government of Western Australia’s Department of Mines, Industry Regulation
Figure 3—Levies assessed and paid 2014–2023 — Source: (Government of Western Australia, 2023)
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
and Safety (DMIRS) and Department of Mines and Petroleum (DMP), to examine how South Africa and Western Australia finance the rehabilitation of legacy mines. Through this desk-based approach, the study critically evaluates the strengths and limitations of each model and advances evidence-informed recommendations to strengthen South Africa’s rehabilitation framework.
Purposive sampling guides the selection of the two jurisdictions due to their contrasting regulatory architectures and the relevance of their experiences to South Africa’s policy debates. Western Australia is selected because it faces a similarly extensive legacy mine challenge. Australia has an estimated 60,000 abandoned mines, with Western Australia accounting for approximately 138,203 hectares of abandoned mine land, only a small portion of which is under rehabilitation (Callari, 2020). Its transition from unconditional performance bonds (UPB) to the levy-based MRFA provides a valuable counterpoint to South Africa’s state-funded approach (Government of Western Australia, 2021). To ensure conceptual clarity, legacy mines in this study refer to pre-MPRDA and pre-NEMA abandoned sites that never made financial provision and therefore constitute a direct state liability.
Data are analysed through a thematic approach structured around two themes. The first theme, financial rehabilitation mechanisms, examines how each jurisdiction designs and implements financial provisioning systems, including levy structures, cost calculations, fund architecture, and long-term liability measures. The second theme, observed performance outcomes, assesses empirical evidence of rehabilitation progress, budget adequacy, institutional effectiveness, and implementation gaps using audit reports, government datasets, and official evaluations. These themes inform an assessment of the legislative and policy effectiveness of each framework, NEMA's 24P, MPRDA's ss 41, 45–46, and the MRFA ss 5–8, based on criteria such as statutory clarity, financial reliability, enforcement capacity, alignment with the polluter-pays principle, and overall sustainability.
As discussed in the aforementioned, both South Africa and Western Australia have enacted legislation to regulate the financing of mining rehabilitation, though they do so through distinctly different institutional and fiscal arrangements. While both jurisdictions acknowledge the severe environmental and public health risks posed by abandoned and unrehabilitated mines, South Africa’s MPRDA and Western Australia’s MRFA diverge significantly in their operative mechanisms, scope, and enforcement effectiveness.
In South Africa, section 46(1) of the MPRDA authorises the Minister of Mineral Resources and Energy to intervene directly to address environmental damage caused by mining activities, particularly when the responsible operator cannot be identified or has ceased to exist. Section 41(1) of the Act further requires mining right applicants to make financial provision for rehabilitation, decommissioning, and closure before the commencement of operations (MPRDA 2002, ss 41(1), 46(1)). These provisions embed rehabilitation obligations into the Act’s environmental management framework and ostensibly provide the state with the authority and resources to act where operators fail. However, in practice, financial provisions are frequently underestimated, inconsistently managed, or rendered insufficient when rehabilitation becomes due. Enforcement under section 46(1) has also been constrained by institutional capacity limitations, leaving the state unable to
operationalise its residual liability under section 45 (MPRDA 2002, s 45). Although the legislative framework signals a strong policy commitment to environmental remediation, the persistent backlog of abandoned mines demonstrates that the state-led intervention model has not been effectively implemented.
This gap between legislative intent and practical outcomes is starkly illustrated by the rehabilitation data presented in Figure 1. Progress in rehabilitating DOMs remain far below national targets set for 2030 and beyond. The magnitude of this deficit raises serious questions about whether the Minister is fully complying with the statutory mandate to ensure rehabilitation where no responsible party exists (MPRDA 2002, s 46(1)). Given the well-documented socio-ecological harms associated with legacy mines, the failure to utilise these legislative tools more effectively undermines the protective purpose of the MPRDA and NEMA compromises intergenerational environmental justice.
By contrast, Western Australia’s MRFA establishes a more coherent and financially sustainable architecture for managing rehabilitation liabilities. Section 8(2) of the Act establishes the MRF, financed through annual levies paid by active mining companies (MRFA 2012 (WA), s 8(2)). Unlike South Africa’s mine-specific, full-cost liability model, the Western Australian system is based on a disturbance-based levy calculated using the formula: "Levy"="RLE"×"FCR", with standardised rehabilitation rates for disturbance categories set out in Schedule 1 of the MRF Regulations 2013 (WA) (MRF Regulations 2013 (WA), Sch 1). This pooled fund structure ensures that resources are consistently available to address rehabilitation needs, regardless of whether the original operator remains extant. The MRFA also permits the use of investment income for additional purposes, including rehabilitating sites not initially listed in the Act, public education activities, and administrative costs associated with the Fund’s management (MRFA 2012 (WA), s 8(2)). This flexibility enhances the Fund’s ability to respond to emerging rehabilitation priorities and reinforces longterm financial sustainability.
Taken together, South Africa’s model places strong normative emphasis on individualised liability and comprehensive coverage of long-term environmental risks, including acid mine drainage, post-closure monitoring, and water treatment obligations (NEMA 1998, s 24P; MPRDA 2002, s 41). Western Australia, in contrast, prioritises risk pooling, administrative efficiency, and secure funding for abandoned and legacy sites (MRFA 2012 (WA), s 8).
Observed performance outcomes
As noted previously, although the South African government set an ambitious target in 2010 to rehabilitate approximately 2,000 DOMs by 2021, within a broader objective of addressing all 6,100 DOMs by 2038, progress has been markedly slower than anticipated. Despite longstanding recognition that DOMs pose significant environmental hazards and far-reaching socio-economic consequences, rehabilitation efforts remain fragmented, inconsistently coordinated, and inadequately resourced. By 31 March 2021, none of the 2,322 high-risk commodity DOMs, arguably the most hazardous category, had been rehabilitated. Even asbestos mines, which present acute and well-documented public health dangers, show minimal progress: only 32 of the 261 identified sites (12%) have been rehabilitated since the programme began in 2006–2007, leaving 229 sites requiring urgent intervention. At the current rate, achieving the asbestos rehabilitation target by 2033 appears highly unlikely without substantial changes in strategy, resource allocation, and political prioritisation.
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
Similarly, while 507 of the 1,170 holings (43%) recorded in the s database have been closed, such administrative closure does not necessarily translate into physical rehabilitation or reduced environmental risk. The incremental increase in annual rehabilitation rates, from 1.67% in 2009 to 2.25% in 2021, signals procedural rather than structural improvement and remains disproportionate to the magnitude and urgency of the challenge. This slow pace raises fundamental concerns regarding institutional effectiveness, financial resourcing, and the seriousness with which the DOMs crisis is being addressed. The widening gap between policy commitments and practical outcomes suggests that, without significant institutional reform, the 2038 rehabilitation target will remain aspirational rather than achievable. A comprehensive reassessment of the current rehabilitation framework is therefore critical, including consideration of stronger enforcement, deeper public-private collaboration, and innovative financing arrangements capable of accelerating rehabilitation outcomes.
Since the inception of the DOMs rehabilitation programme, the National Treasury’s persistent failure to allocate adequate funding has deepened the disconnect between statutory obligations and fiscal prioritisation. This chronic underfunding is particularly concerning given the substantial risks DOMs pose to public health, environmental integrity, and local socio-economic stability. The tendency to direct MTEF allocations primarily towards asbestos rehabilitation and the holings programme, while overlooking the 2,322 high-risk commodity DOMs, reflects a narrowly focused and fragmented funding strategy. By neglecting a comprehensive, long-term fiscal approach, the state is effectively deferring an expanding environmental liability and escalating the eventual cost
Table 1
of rehabilitation. This approach undermines the constitutional duty in section 24 of the Constitution to safeguard the environment for present and future generations.
The 2021 valuation report’s estimate that R3.86 billion is required to rehabilitate the remaining 229 asbestos mines by 2033, of which only 44% (R1.69 billion) is currently available, highlights serious deficiencies in fiscal planning and commitment. The projection that full funding will only be secured by 2043 renders the 2033 target practically unattainable. That asbestos rehabilitation alone requires a 20-year timeline under current conditions casts significant doubt on the realism of the broader target to rehabilitate all 6,100 DOMs by 2038. Compounding the financial challenges is the misalignment between budget allocations and Mintek’s technical and operational capacity to design and implement rehabilitation projects. This gap reflects broader institutional inefficiencies, including weak coordination, insufficient integration of financial and operational planning, and the absence of adaptive management practices. The resulting discrepancies between projected and actual completion timelines, as illustrated in Figure 2, raise serious concerns about the overall feasibility of the DOMs rehabilitation programme.
Turning to Western Australia, and recalling the reported AUD42.8 million in mining rehabilitation levies collected in 2022–2023, a 9.2% increase from the previous year, appears encouraging in terms of financial mobilisation. Levy compliance is high at 97.5%, and the Mining Rehabilitation Fund (MRF) holds a total of AUD291.2 million, including AUD3.1 million in interest earnings. However, several structural challenges warrant attention. The reliance on interest earnings to support legacy mine
A comparison of South African and Western Australian models for financing the rehabilitation of legacy mines
Dimension
Legal basis
System type
South Africa – NEMA financial provision (FP) & MPRDA
NEMA s 24P; FP Regs 2015; MPRDA ss 41, 45, 46.
Mine-specific, full-cost financial provisioning.
Primary purpose Secure full rehabilitation, closure, and longterm liabilities per mine.
Funding model State-funded for pre-MPRDA and pre-NEMA sites; budget constrained.
Fund structure No pooled fund: state assumes costs where operators are absent.
Calculation basis Detailed costing of progressive, closure, and latent impacts.
Fund rehabilitation of abandoned and legacy sites.
Self-sustaining levy based on annual disturbance.
Principal for authorised sites; interest in legacy sites.
Levy = 1% of RLE (hectares × Schedule 1 rates).
Standard categories: pits, dumps, tailing storage facilities, plant areas.
Responsibility model Individual operator liability (polluter-pays). Shared industry responsibility via a pooled fund.
Performance Slow rehabilitation; large unfunded backlog. Strong levy compliance, but rehabilitation lags new disturbance.
Governance challenges Fragmented administration; weak enforcement. Reliance on investment income.
Strengths Strong long-term liability provisions. Simple, predictable, and sustainable funding.
Limitations Financially unstable for legacy mines. Levy insufficient for full-cost closure; diluted polluter-pays.
Source: Authors' compilation (2025)
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
rehabilitation introduces a degree of financial volatility. While innovative, this approach exposes rehabilitation funding to market fluctuations, creating uncertainty during periods of economic downturn or low interest rates. Given the enduring nature of environmental risks associated with abandoned mines, the stability of rehabilitation financing should not depend on financial market performance alone. Additionally, although the Fund has supported targeted initiatives, such as the Safer Shafts for Towns and Legacy Tailings programmes, the thematic scope of these projects appears narrow and does not address systemic issues such as large-scale contamination, land degradation, and ecosystem restoration. The limited range of funded initiatives suggests that rehabilitation efforts may be proceeding in a piecemeal fashion rather than through a coordinated, landscape-level strategy. Table 1 presents a comparative overview of the South African and Western Australian financing models for the rehabilitation of legacy mines.
Lessons for South Africa
The comparative financial models demonstrate that South Africa can draw several important lessons from Western Australia’s approach to mine rehabilitation, particularly regarding the design of a sustainable, accountable, and efficient funding system. As shown in the comparative table, South Africa’s current regime under section 24P of the NEMA, the Financial Provisioning Regulations, 2015 (GN R1147), and section 46(1) of the MPRDA places full-cost rehabilitation liability on individual operators (NEMA 1998, s 24P; Financial Provisioning Regulations 2015; MPRDA 2002, s 46(1)). However, where companies are untraceable or liquidated, the state assumes responsibility under section 45 of the MPRDA (MPRDA 2002, s 45). This state-funded model has proven financially unstable, particularly given the National Treasury’s persistent failure since 2010 to allocate adequate funding to meet the national target of rehabilitating all DOMs by 2038.
In contrast, Western Australia’s MRFA and MRF Regulations 2013 (WA) establish a self-sustaining, industry-wide pooled levy that generates predictable revenue for abandoned and legacy
Table 2
sites (MRFA 2012 (WA); MRF Regulations 2013 (WA)). The legislation provides a clear fund architecture, section 6 establishes the Mining Rehabilitation Fund Authority, section 8 outlines fund utilisation, and Schedule 1 of the Regulations sets standardised disturbance categories and rehabilitation rates (MRFA 2012 (WA), ss 6, 8; MRF Regulations 2013 (WA), Sch 1). The distinction between principal contributions and investment income further enhances financial stability by allowing interest revenue to be applied to older or unlisted sites. South Africa could therefore benefit from introducing a mandatory industry levy, supported by explicit legislative provisions governing levy collection, fund administration, transparency requirements, and independent oversight. Such a model would reduce reliance on unstable state budgets, enhance financial independence, and ensure continuity of DOMs rehabilitation.
The comparison also highlights the need to improve accountability, transparency, and administrative efficiency in South Africa’s system. Western Australia’s high levy collection efficiency (97.5%), simplified disturbance-based calculation method, and transparent fund reporting processes provide valuable benchmarks (MRFA 2012 (WA); MRF Regulations 2013 (WA)). By contrast, South Africa’s financial provisioning system remains administratively complex, financially burdensome for smaller operators, and weakened by persistent enforcement challenges. Introducing a streamlined, industry-wide funding mechanism with mandated reporting and external oversight could help prevent mismanagement and strengthen rehabilitation outcomes.
Additionally, performance trends from Western Australia indicate that newly created mining disturbances can outpace rehabilitation progress, reinforcing the need for South Africa to integrate proactive mine closure planning, enforce progressive rehabilitation, and embed stringent post-closure monitoring obligations to prevent growing backlogs. Finally, the strengths and weaknesses of the two systems underscore the importance of balancing environmental protection with financial feasibility: South Africa’s approach provides comprehensive long-term liability
Summary of lessons for South Africa from Western Australia's models for financing legacy mine rehabilitation
Category
Sustainable financing
Legislative enforcement
Accountability and efficiency
Rehabilitation capacity
Balancing disturbance and rehabilitation
Lessons for South Africa
Introduce a mandatory levy to establish a self-sustaining rehabilitation fund, reducing reliance on limited government budgets and ensuring predictable funding for DOMs.
Strengthen enforcement of NEMA s 24P, FP Regulations, and MPRDA s 46(1) through clear guidelines on levy collection, fund use, and accountability.
Enhance fund governance by implementing transparent reporting and efficiency benchmarks, similar to Western Australia’s high levy collection rate.
Increase capacity and funding to accelerate rehabilitation of abandoned mines and reduce community and environmental risks.
Implement proactive closure planning and stricter progressive rehabilitation to prevent new mining disturbances from exceeding rehabilitation progress.
Responsibility model Shift towards a shared industry responsibility system, reducing pressure on state budgets for abandoned mines.
Long-term liabilities
Sustainable development
Source: Authors' compilation (2025)
Maintain strong long-term liability coverage (e.g., AMD and water treatment) supported by more reliable funding mechanisms.
Promote a well-funded, long-term rehabilitation system to support environmental recovery and socio-economic stability in mining areas.
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
coverage, particularly for acid mine drainage, water treatment, and residual impacts, but its instability regarding abandoned mines demonstrates the value of a pooled industry responsibility model similar to Western Australia’s.
By adopting these lessons, South Africa can accelerate DOMs rehabilitation, strengthen long-term environmental governance, and support sustainable development in mining-affected communities. Table 2 presents a summary of key lessons for South Africa drawn from Western Australia’s model for financing legacy mine rehabilitation.
Discussion
The findings of this study demonstrate clear contrasts between the financial rehabilitation models of legacy mines in South Africa and Western Australia, reflecting broader patterns highlighted in the environmental governance literature. South Africa’s framework, grounded in the Constitution’s environmental right (Republic of South Africa, 1996), NEMA’s full-cost financial provisioning requirements (NEAMA 1998, s 24P; DEA 2015), and the MPRDA’s provisions for state intervention (MPRDA 2002, ss 41, 45, 46), is normatively strong and closely aligned with the polluter-pays and duty-of-care principles discussed by Kenehan (2022) and Ashukem (2024).
However, the empirical evidence reveals severe implementation shortcomings: despite commitments to rehabilitate 2,000 DOMs by 2021 and 6,100 by 2038, virtually no high-risk mines and only 12% of asbestos mines have been rehabilitated, while annual progress has stagnated at under 3% (Auditor-General South Africa, 2021). The chronic underfunding by the National Treasury, combined with limited institutional capacity and slow implementation by Mintek, has produced a growing gap between planned and actual rehabilitation timelines, now extending into the next century, which undermines South Africa’s constitutional obligations and confirms broader governance observations that legislative ambition without effective implementation yields limited environmental outcomes (Ashukem, 2024).
In contrast, Western Australia’s model, anchored in the Mining Rehabilitation Fund Act 2012 (WA) and the Mining Rehabilitation Fund Regulations 2013 (WA), implements a pooled, levy-based system in which mining operators contribute 1% of their rehabilitation liability estimate (MRF Regulations 2013 (WA); MRFA 2012 (WA)). This disturbance-based model, supported by standardised Schedule 1 rates and investment income, has generated stable revenue, with a 97.5% levy collection efficiency and a fund balance of AUD291.2 million (Government of Western Australia, 2023). Yet, despite the financial strength of the MRF, the area of active disturbance has expanded more rapidly than the area under rehabilitation, revealing a structural imbalance that aligns with scholarly concerns regarding the limits of financial instruments when not paired with strong closure-enforcement mechanisms. These comparative findings have important practical, theoretical, legal, and policy implications. Practically, they show that South Africa’s reliance on state-funded rehabilitation for legacy mines is unsustainable and inconsistent with its ambitious legal framework, while Western Australia illustrates the advantages of a predictable, ring-fenced funding model. Theoretically, the comparison deepens understanding of environmental liability frameworks by contrasting South Africa’s strict, individualised polluter-pays model, reflected in section 28 and section 24P of the NEMA (NEMA 1998, ss 28, 24P), with Western Australia’s sharedresponsibility approach through a pooled industry fund.
Legally, the analysis underscores that South Africa’s regime is comprehensive but lacks a statutory pooled mechanism for financing legacy mine rehabilitation, leaving the state financially exposed under section 45 of the MPRDA (MPRDA 2002, s 45).
In contrast, Western Australia’s MRFA demonstrates how clear statutory authority, structured fund governance, and detailed investment income provisions enhance long-term financial sustainability, particularly section 8(2), which authorises the use of investment income for additional rehabilitation-related purposes (MRFA 2012 (WA), s 8(2)). Policy-wise, the study highlights the need in South Africa for greater administrative simplicity, improved cross-departmental coherence, stronger enforcement of progressive rehabilitation, and more realistic rehabilitation target setting.
The study acknowledges several limitations, including reliance on secondary data, a limited two-jurisdiction comparison, and incomplete disclosure of long-term rehabilitation liabilities. Future research should incorporate empirical fieldwork with regulators, companies, and communities; expand comparisons to additional jurisdictions; model fund sustainability under different levy rates; and examine the socio-ecological implications of alternative rehabilitation funding architectures.
Conclusion and recommendations
This article successfully unpacked the different approaches and strategies of DOMs rehabilitation in South Africa and Western Australia. It was observed that South Africa’s efforts to rehabilitate DOMs faced significant challenges because of financial constraints, administrative inefficiencies, and inconsistent government funding. Even though the MPRDA empowered the state to address these issues, the reliance on direct government allocations has hindered sustainable progress. In contrast, Western Australia's MRF provides a more structured and financially self-sustaining model, ensuring continuous rehabilitation efforts through a levy-based system.
To improve the rehabilitation of abandoned mines, this article argues that South Africa should consider adopting a dedicated rehabilitation fund like the MRF, funded through mandatory levies on mining companies. This approach would help create a predictable and sustainable financial mechanism, reducing reliance on discretionary state funding. Additionally, strengthening enforcement measures and improving interdepartmental coordination would enhance efficiency in South Africa’s rehabilitation efforts. By implementing these reforms, South Africa can accelerate ownerless mine rehabilitation, mitigate environmental and socio-economic risks, and promote sustainable land use in mining-affected communities. Acknowledgement
The authors wish to express gratitude to the National Research Foundation (NRF) of South Africa (Grant number RPCLES231215201427) for funding this research and declare that no competing interest exists.
Credit author statement
F.A. and J.C. contributed equally to all aspects of the research except for funding acquisition, which was undertaken solely by FA. Both authors contributed to:
• Conceptualisation
• Methodology
• Investigation
• Data curation
• Writing – original draft
• Writing – review and editing
• Formal analysis
• Supervision
Comparative legal solution for rehabilitating legacy mines through financial provision in South Africa and Western Australia
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Affiliation:
1Mesong Holding, South Africa
Correspondence to:
X. Gumede
Email:
xolanigumede@mesongholding.co.za
Dates:
Received: 5 Oct. 2022
Revised: 24 Feb. 2025
Accepted: 4 Dec. 2025
Published: December 2025
How to cite:
Gumede, X. 2025. The blast-induced noise and ground vibration structural and human response: A case for the South African mud house homes. Journal of the Southern African Institute of Mining and Metallurgy, vol. 125, no. 12, pp. 737–748
DOI ID: https://doi.org/10.17159/2411-9717/2354/2025
The blast-induced noise and ground vibration structural and human response: A case for the South African mud house homes
by X. Gumede1
Abstract
Mud houses are common structures in most South African rural homes closer to the mining operations. Fulltime dwellers in these properties are often the elderly. The mine codes of practice and the South African legislative instruments attempt to define the damage criteria to limit the effect of the blast-induced noise and ground vibrations to different structures. All these assessment criteria are based on the peak particle velocity and noise generated during blasting. The South African safe limit criterion that was adopted was initially derived from the international standards, which were then used as a local guideline. This paper evaluates the currently adopted safe limit criteria used in South Africa for a mud house, currently rated at 6 mm per second and 120 decibels to134 decibels, for blast-induced seismicity and noise, respectively. Further, a study was performed on a residential house near a coal mine (5.26 km) based in Mpumalanga following numerous complaints by the owner, launched at the mine and to the Department of Minerals and Petroleum Resources. The aim of the study was to measure the magnitude of blast-induced triggers experienced at the aggrieved homestead and to establish if there is a likelihood that an irritation or damage may be caused by these triggers. The seismometer was installed at about 2 m from the mudhouse, from 1 July 2022 to 31 of July 2022. Five blast-induced triggers were recorded during the period showing an average of 0.09 mm/s and 121 decibels for blast-induced seismicity and noise, respectively. The results obtained indicated a maximum seismicity of 0.15 mm/s. This seismicity was below the perceptible vibrations obtained from daily home activities such as walking, jumping, and door slamming, which produce 0.8 mm/s, 7.1 mm/s, and 12.7 mm/s, respectively. Seismicity was therefore not likely to have caused any annoyance and or damage. For noise, the results indicated a maximum of 123 decibels and an average of 121 decibels from five events recorded. A literature review suggests that slight damage may occur when airblast frequencies match the natural frequencies of structures at 120 decibels. Based on these results, it can be concluded, therefore, that the noise, rather than seismicity, is more likely to be the cause of damage to the structure assessed. For improvement, a new approach is proposed based on relating the safe limits to the structural and human response.
Keywords
mud houses, South African rural homes, safe limit criteria, structural response, blast induced annoyance and damage
Introduction
Blasting is a common rock breaking technique used in mining. It provides the primary energy required to break the rock into fragmentation sizes as may be required by the subsequence downstream mining value chain processes1. During blasting, a large quantity of energy is released. The corresponding pressure and temperature produced during blasting is approximately 50GPa at about 230°C, respectively (Prashanth, Nimaje, 2018). Only 20%–30% of the explosive energy2 is used to break the rock. The rest of the energy is dissipated through ground vibration, fly rocks, back breaks, and air overpressure (Prashanth, Nimaje, 2018). A wave train is generated when explosive charges are detonated in a solid medium such as a rock. These waves generate different particle movements and travel at different wave velocities. The resulting ground-borne vibrations may have an effect on residential buildings. The effect may range from negligible effects to severe threshold human and structural impact. Different
1The downstream processes include loading of the muck-pile, hauling and primary–tertiary beneficiation.
2Useful energy is the energy used to break and move the rock according to the blast design distance and muck-pile profile or shape (International Society of Explosives Engineering, 2021).
The blast-induced noise and ground vibration structural and human response
structures and people respond differently to the blast-induced noise and ground vibration. The magnitude of the impact is therefore dependent on the structural or human response. The blast-induced noise and ground vibration is the principal public mining nuisance. It may scare people and livestock and damage or even collapse structures near the blasting source (Yan et al., 2016).
The blast-induced noise and ground vibration are a major source of complaints from the communities staying closer to the mines. The common complaints are as a result of structural damages believed to be caused by the blasting activities from the mine. Between the mines and complainants, it is a common cause that blasting generates ground vibration and noise. The noise and ground vibration may have a damaging effect on both structures and humans. Many countries established their own national standards to guard against the blast-induced noise and ground vibration impact. The countries that do not have their own standards usually adopt the set limits from countries that have. South Africa is one of the countries that, during the time of this study, did not have its own standards for blast-induced noise and ground vibration. South Africa has adopted the widely used United States Bureau of Mines Standard (USBM-RI 8507) to control the blast-induced noise and the ground vibration impact from mines on the communities and structures in close proximity to the mining operations. While different international standards cover the structural impact of blasting, there is still no internationally accepted blasting vibration assessment criteria on humans and specific structures of a unique design. The underplaying of the human impact factors in the then set limited criteria suggested that the houses near the mines were treated as structures and not as homes where humans stay. The criteria were focused on guarding against structural damages and omit the psychological, emotional, and physical impacts that the people who stay in these homes are likely to suffer.
The blast-induced noise- and ground vibration-related complaints trigger civil disputes between inhabitants and mining companies. The disputes between the inhabitants and the mining companies pose a direct threat to the South African economy. For this reason, this study suggests that blasting must be strictly controlled in environmentally sensitive areas. Engineering controls based on well-established scientific knowledge must be applied. Administrative controls must be used to further address technical issues and other challenges that may be encountered.
Objectives of the study
The objectives of this study were:
➤ To evaluate the currently adopted safe limit criteria used in South Africa for a mud house.
➤ To measure the magnitude of the blast-induced noise and seismicity at the mudhouse homestead.
➤ To assess the likely cause for damage and or annoyance.
➤ Make appropriate recommendation.
International standards on blast-induced noise and ground vibration
A large number of studies in the area of blast-induced noise and seismicity have been conducted since the early 1920s. The studies aimed to investigate the impact of the blast-induced noise and ground vibration on structures and their response (SayedAhmed, Naji, 2006). Various standards and codes of practice were established as a result of the studies. These standards proposed different safe limits for the blast-induced noise and seismic impact on structures and humans. The main international standards used
are the United States Bureau of Mines Standard (USBM), the United States Office of Surface Mining (OSM), the British Standard, and German and Swiss Standards (Yan et al., 2016). China National Standard (GB6722-2014, 2014), India CMRS (Dhar et al., 1993) and Australian Standards (CA 23,1967) are not widely used but are internationally recognised.
The United States Bureau of Mines standard, commonly known as USBM-RI 8507, is a widely adopted criterion (Dowding et al., 2018). It is a standard criterion for safe limits against structural and threshold damage of buildings due to ground vibrations generated by blasting. After implementing this criterion, it was important to assess the structural and human responses. This initial state of the USMB criterion could not prevent the frequent complaints from residents complaining about blast-induced seismicity impact. An alternative USBM frequency-based safe limit was proposed, which took into account the effect of the dominant vibration frequency to assess the effect of ground vibration on structures (Siskind et al., 1980). The USMB-RI 8507 criterion was modified in 1992 by the US Office of Surface Mining (OSM) to reflect updated methodologies and findings in the assessment of geological and geotechnical conditions relevant to mining operations. Also, the modification was based on the scaled distance formula3, which considers the number of explosives per delay and the distance between the structure and the blast. The scaled distance method is considered as the conservative peak particle velocity (PPV) prediction method (Sayed-Ahmed, Naji, 2006). Britain uses the British Standard BS 7385 criterion for safe limit against blast-induced ground vibrations. This standard is comparable to the OSM criterion. The BS 7385 criterion separates buildings according to their sizes. This is done by adopting two lines for the safe limit, which are for large and small buildings (Sayed-Ahmed, Naji, 2006). Another commonly used standard is the German and Swiss Standards Criterion the DIN 4150. The two criteria are significantly conservative compared to the American and British criteria (Sayed-Ahmed, Naji, 2006). It is generally argued that the DIN 4150 criterion is not damage-based but rather intended to minimise the perceptions and complaints of house residents who live adjacent to blasting sites (Sayed-Ahmed, Naji, 2006).
The four main blast-induced monitoring standards were developed by four countries, namely the United States of America (USBM and OSM), Britain (BS 7385), Germany, and Switzerland (DIN 4150). The USBM and the OSM came about from a technical exercise, i.e., a 10-year research programme. It was aimed at establishing the safe limits for mainly structures, with the expectation that, once the safe limits had been established, the human complaints would be resolved. This goal was not achieved as the complaints from people residing closer to the mines continued (Yan et al., 2017). The British proposed the idea that the size of the house matters. The BS 7385 introduced a two-lines method for the smaller and larger buildings. This was not based on in-depth research such as that of the USBM. The American and British standards may be seen as a technical approach in solving the blast-induced noise and seismicity impact on structures and
3PPV, is the forecast peak particle velocity defined by the equation a . The factor R/√W defines the scaled distance. R is the distance from the blast to the structure. W is the mass of charge per delay in kg. The constants a and b are site-specific constants that are a function of the transmission properties of the rock mass. The standard values for a and b are 0.800 and 1.600 for predictive assessment prior to the establishment of actual values.
The blast-induced noise and ground vibration structural and human response
humans. The Germans and Swiss seem to have followed a tactical approach as opposed to a technical approach, in that they applied an engineering judgement on an already established technical content. Their approach can be equated to a stakeholder management administrative tool that seeks to manage the conflict between the mine and residents.
South African standards and guidelines on
blast-induced
noise and ground vibration
South Africa did not have a standard for the blast-induced noiseand ground vibration (DMRE, 2020). This regulatory void prompted the Mining Regulations Advisory Committee (MRAC) to establish a task team to facilitate the development of the guidance note on a minimum standard regarding ground vibration, noise, airblast, and flyrock (Department of Mineral Resources Mine Health and Safety Inspectorate, 2020). This guideline was developed to provide a framework to manage the risk of ground vibration, noise, air blast, and flyrock. No in-depth local research was done, such as in the case of the USBM, but instead, the guidance note was designed around best practices, principles, and standards. It was developed for the mining industry to align with international best practices and current South African mining laws.
The Mine Health and Safety Act (MHSA) of 1996 (Department of Mineral Resources, 2020) makes provisions in the interest of safety for the people not working at the mine who may be affected by the activities at the mine. Section 5(2) of the MHSA provides that, as far as reasonably practical, every employer must identify relevant hazards and assess the risk to which persons who are not employees may be exposed. It further requires the employer to ensure that persons who are not employees, but who may be affected by the activities at the mine, are not exposed to any hazard to their health and safety. According to the MHSA Regulation 4.16(2), blasting within 500 m of surface structures must be protected. The Department of Mineral and Petroleum Resources (DMPR) directive released on 27 February 2020 requires that all opencast mines in Mpumalanga, operating within close proximity to the communities (within 500 m–2000 m), must ensure the protection of their structures, specifically from blast-induced hazards. The Government Gazette issued on 2 August 2024 directed that all opencast mines operating within a 2,000 m proximity to the communities develop and implement a mandatory code of practice (MCOP) according to the guidelines provided by the DMPR for the minimum standards on ground vibrations, noise, air-blast and flyrock near surface structures and communities to be protected, effective from 1 November 2024. The MCOP developed in accordance with the DMPR guidelines is used as a self-regulatory instrument by the mines and the DMPR to enforce compliance and protection of the structures and communities. Furthermore, the South African standard for ground-borne vibration measurements exists as part of the South African National Standard (SANS) 4866:2011). The South African Bureau of Standards adopted standard IS04866 of the International Organisation for Standardisation (ISO). This standard provides guidelines for measuring vibrations and evaluating their effects on fixed structures but does not provide safe vibration limits on structures.
Prior to the implementation of the MCOP, the USBM standard R18507 was the adopted standard in South African. It was generally used as a guideline to assess whether ground vibrations exceed safe limits. According to the Mine Health and Safety Inspectorate (2020), the South African mining communities were generally unhappy with the standards used. The damage and/or deterioration
of their buildings were continuing, allegedly, as a result of the blasting activities from the mine. The MHSI (2020) further stated that the communities reported that they generally do not receive warnings of blasting activities. They experience anxiety and fear due to sudden blasting without prior notice. The procedures for lodging complaints were not clear to the community members, and they had little hope of recourse should they not receive a satisfactory response from the mine. Community surveys show that there are high levels of distrust between the communities and the mines (MHSI, 2020).
It was concluded that, before those of 1 of November 2024b, there were no statutory limits laid down in South African law concerning the blast-induced noise and seismicity safe limits for structures and humans. The onus was placed on the mine owner to ensure that the blasting operations do not cause damage to private property. The mine owner, in turn, relies on advice from experts such as engineers employed by the major suppliers of explosives or independent consultants (MHSI, 2020). The recent (1 November 2024) MCOP guidelines has provided guidance on the overall management of blast-induced noise, airblast, ground vibration and flyrock. Even with this intervention, it seems like there are still gaps within the system that have not been well addressed.
The prediction algorithms and structural response
Ground vibrations are the inevitable results of confined explosions. The rock close to the borehole is crushed or fractured (typically in the zone within 30-times that of the hole diameter) (Altunışık et al., 2021). A proportion of the energy is radiated as elastic energy in the form of compressional (P) and shear (S) waves (International Society of Explosives Engineering, 2021). Any vibrational energy that travels beyond the zone of rock breakage is wasted, only causing annoyance and damage (Mpofu et al., 2021). The class of seismic waves that distort the earth's surface most severely are known as surface waves. Surface waves have both vertical and horizontal compressional components of shear. Their effect on buildings depends on the wavelength of the waves, the footprint, and the height of the buildings (Adepitan et al., 2018). The seismic wavelength, in turn, depends on the charge mass, the seismic velocity of the rock, and soil that comprises the near-surface layer of the earth, which is usually the uppermost 10 m–30 m (Behzadafshar et al., 2018). Surface wave velocities (c) for near-surface materials typically range from 200 m/s (alluvium) to 2,000 m/s (slightly weathered granite). The particle velocity (V) is entirely different from wave velocity (c). The frequencies (f) produced by a typical blast in an open cast mine range from 5 Hz–200 Hz (Behzadafshar et al., 2018). The wavelength (C] = c/f) thus ranges from 1 m to 400 m. The potential to cause damage to buildings is greatest when the wavelength is of the same order as the footprint of the building (Yan et al., 2021). The potential to cause damage to buildings is most closely correlated with the peak particle velocity (PPV). The damage is not only to structures, as this study also seeks to focus on the human element. Dowding et al. (2018) state that humans can detect ground motions with PPV as low as 0.8 mm/s. Buildings may experience cosmetic damage at PPV of 10 mm/s at frequencies of 10 Hz. Severe structural damage may occur when PPV exceeds 200 mm/s (Adepitan et al., 2021).
Particle velocity (V) depends on the amount of energy released by the explosive and the distance from the blast. The intensity of PPV is influenced by several parameters, namely, physical properties of rock mass, explosive characteristics, and blast design parameters like spacing, burden, number of holes, hole diameter,
The blast-induced noise and ground vibration structural and human response
hole depth, distance from blast source, maximum explosive charge per delay, delay time, and stemming (International Society of Explosives Engineering, 2021). In light of the aforementioned, blast-induced ground vibration evaluation and prediction are important for the prevention of substantial damage to surrounding structures and dwellings. Several researchers have suggested various methods and empirical predictors to control the harm of ground vibration levels during blasting. All the empirical predictors are based on the maximum charge per delay and the distance from the blasting source to the structure (Adepitan et al., 2021). The vibration safety criterion should be established first to evaluate the blast-induced dynamic response effect and prevent the structures from being damaged. A scientific survey on representative houses and cracks should be conducted before and after blasting. This must be accompanied by understanding the demographics and other conditions of those who live in those properties. The study that seeks to establish the structural and human conditions of the surrounding mine communities is referred to as a pre-blast structural and census survey.
The prediction and response of the structure to blast-induced seismicity is done through an established mathematical logic. Under the action of stress wave, the tensile stress is generally responsible for cracking or damaging of structures, and particle velocities and frequencies are typically monitored during blasting (Dowding et al., 2028). Therefore, calculations based on plane wave conditions may provide a simple relation between measured particle velocities, frequencies, and expected response of the structures (Yan et al., 2016). Equation 1 expresses the one-dimensional stress wave theory:
where σ represents stress, Pa; ρ is the average density of stress wave spreading field, kg/m3; CR is the average surface wave velocity, m/s, and V is the absolute value of the PPV at a certain distance away from blast source, which is dependent on the surface seismic wave propagation, m/s. Once the dynamic tensile strength of the protected structure (δt) is given, Equation 1 can be rewritten as follows:
The relationships among the propagating velocity of P wave (CP) and S wave (CS), dynamic elastic modulus of medium (E), and dynamical Poisson’s ratio of medium (µ) are as follows:
Substituting Equation 4 into Equation 5 obtains Equation 6:
Surface waves are called Rayleigh waves. They travel along the surface of a solid medium, unlike body waves (P-waves and S-waves), which travel through the interior. The velocity of the R wave (CR) is independent of frequency and is related to the elastic
constants of the medium. It can be approximately calculated with Equation 7: [7]
Houses with weaker foundations or even soil foundations have weak shock resistance capability (Yan et al., 2016). The value µ = 0.23, the average density of stress wave transmitting field ρ is 2500 kg/m3, and the velocity of P wave (CP) is about 3000 m/s–3500 m/s (Xu, 2012). The dynamic tensile strength of foundations can be thought of about 1/10–1/20 of seriously weathered rock mass (namely δt = 0.05 - 0.1 MPa) (Yan et al., 2016). This mathematical logic presents important information that could assist in guiding the establishment of the South African mud house blast-induced seismicity safe limits as proposed in this study. Isolated practical experiments conducted internationally and locally could be used to form a practical base that would be weighed against the theoretical base.
Human response to blast-induced noise and seismicity
According to Yan et al. (2016) humans can perceive ground vibration at levels as low as 0.8 mm/s. This is lower than the vibration level, damaging even the most fragile structures. It is important to understand human perception and the ability to feel seismicity. Yan et al. (2017) elaborated on the different levels of seismicity that humans perceive. Yan et al. (2017) indicated that daily life in a family home will produce perceptible vibrations. Such activities include walking, jumping, and door slamming, which produce 0.8 mm/s, 7.1 mm/s and 12.7 mm/s, respectively. Based on this information, it is clear that the main reason for vibration complaints is usually not based on structural damage but rather a psychological effect, which may result from fear of damage and/or nuisance. In line with this view, good public relations and education will help reduce anxiety and complaints (Yan et al., 2017).
The human body is a more complicated and sensitive system than concrete structures. Every part of the human body may respond to vibrations with different frequencies. Thus, the vibration frequency is vital in evaluating adverse effects on humans. It has been observed that the frequency of most concerns regarding environmental vibration is about 1.0 Hz–50 Hz, which covers the resonating frequencies of most human body parts. It also indicates that the vibration with low frequency (1.0 Hz–10.0 Hz) primarily impacts all kinds of viscera, while the middle frequency (10 Hz‒50 Hz) vibration mainly influences muscular tissue and sensory organs (such as the head and the eyeballs). High-frequency (> 50 Hz) vibration mainly acts on the human body's central nervous system and nerve endings (Yan et al., 2017).
Community and individual psychological responses to seismicity involve some subjective attitudes about the kind of environment that is considered acceptable (Yan et al., 2016). Some individuals consider any noticeable responses unacceptable, whether perceived directly or indirectly through the secondary ‘sounds’ of structure responses or even sometimes mistakenly perceived. A case study from an Indiana (USA) coal mine site, which was being performed by the OSM, USBM, and five other federal and state offices (Siskind et al., 1993), revealed that 36 per cent of complaints, supposedly about the ‘strong blasts’, did not correlate in time with blasts at this mine or any mines within the region. Researchers concluded that there will always be complaints about these, and other similar experiences, at other blasting sites. Table 1 shows the safety thresholds for seismicity at specific frequency ranges for humans.
The blast-induced noise and ground vibration structural and human response
Table 1
Safety thresholds of continuous vibration (less than 1 minute) on humans
Table 2
Estimated cracking-threshold PPV for local residences in the construction site of the Baihetan Project
No Residence
3
Internationally-based mudhouse experiment
An experiment at the Baihetan Project in China included a mud brick house, a rough brick house, and a cosmetic brick house. The result indicates that local residences near the construction site do not crack until PPVs exceed 11.7 mm/s–23.5 mm/s, which is identified with Dowding and Siebert's theoretical estimation (2000). The results further confirmed that the predictive assessment of blast-induced cracking threshold of the poor foundation local residences can be estimated according to Equations 1 to 6. The estimated cracking threshold results for the Baihetan Project are given in Table 2.
As a guiding principle, the vibration safety criteria of different countries are always conservative controls because the socially acceptable probability of occurrence of cracking must be taken into consideration. Furthermore, human annoyance has become essential in the blasting industry, especially for repeated blasting operations. According to Yan et al. (2016) the human body can detect PPV at the level of 0.8 mm/s with clearly perceptible levels at 10.0 mm/s. The PPVs needed to cause cosmetic building damage to ordinary structures vary among the different standards worldwide but is typically in the range of 5 mm/s–50.0 mm/s, based on ISO10137 1992, BS7385 1993, and DIN 4150 1999 (Yan et al., 2016). Chiappetta (2000) suggested that the strictest standards must be set to reduce cosmetic damage and decrease the annoyance levels of people to avoid civil disputes between inhabitants and construction companies. Table 3 shows the PPVs at low, medium, and high frequency for various international standards.
Airblast and noise
Airblast and noise are one of the primary sources of complaints (Chiappetta, 2000). The airblast (or overpressure) is the change in pressure and is expressed in decibels (dB). Airblast in the context of opencast mining, is generally the superposition of a number of air pressure pulses produced by the blast-induced explosion (MHSI, 2020). The pressure pulse may be above or below the ambient atmospheric pressure (MHSI, 2020). The wave travels at the local speed of sound. Noise is merely the audible part of the airblast greater than 20 Hz (Dowding et al., 2018). At large distances from a blast, much of the energy may travel at sub-audible frequencies, which cause windows and doors to rattle, which may alarm people. For a South African mudhouse roofed with congregated iron sheets
and stabilised with loose weights, the rattling on the roof may be exacerbated, triggering higher annoyance than expected. Dowding et al. (2018) indicated that the main airblast and noise hazards arise from the energy carried at frequencies lower than the human hearing range. This suggests that rattling, which is felt and heard, may be a result of the undetected sound waves. According to Yan et al. (2017), the rattling of windows and ornaments is likely to occur when airblast frequencies match the natural frequencies of structures. This is possible at 120 dB. The effect of the undetected sound waves may be mistakenly thought to have been caused by seismicity. The airblast is reflected at hard interfaces such as topography and buildings (Espley-Jones, Goetzsche, 2020). The airblast gets refracted when the speed of sound changes due to variations in temperature, humidity, wind speed, and wind direction (Dowding et al., 2018).
Many studies of the human response to air pressure pulses use long durations of steady-state audible noise sources. This is not representative of mining airblasts, which are impulsive (a short duration), have a large infrasonic component (frequency too low to be heard), and are strongly influenced by weather conditions. Thus, human sensitivity is extremely difficult to define because of the vast variable audibility of any particular event (Yan et al., 2017).
The threshold of human hearing at 1 kHz is a sound pressure level of about 20 ÜPa, or 0 dBL (Dowding et al., 2018). This is similar to the noise made by a mosquito at a range of 3 m. The ANSI-1969/1SO-1963 standard uses 6.5 dB SPL (sound pressure level) at 1 kHz as the threshold, with a 10 dB correction applied for older people (16.5 dB) (Dowding, 1985). Normal conversation is 60 dBL–80 dBL, and average street traffic is about 85 dBL (Dowding, 1985). To give a local example of a loud noise, a South African vuvuzela4 at a range of 1 m produces a sound pressure level of 120 dB (Swanepoel et al., 2010). Prolonged exposure to sound pressure levels above 85 dB can cause hearing damage. If the predominant frequency of the event is low (25 Hz), a pressure pulse of 115 dB might be unnoticeable to most people. If the predominant frequency is well into the range of human hearing (20 Hz to 20 kHz for young people), a pulse of the same amplitude might be annoying (Swanepoel et al., 2010).
The blast-induced noise and ground vibration structural and human response
Table 3
International
Loess cave dwellings, adobe buildings
1
Brick houses, large nonseismic block buildings
2 Modern homes, dry wall interiors
China National Standard (GB6722-2014, 2014)
USBM Standard (Siskind et al., 1980) Older homes
3 Civil buildings not belonging to proprietor
Proprietary civil buildings with limited-service life
4
Houses, lowstory residential buildings, general commercial buildings
5 Industrial buildings
India CMRS, (Dhar et al., 1993)
Australian Standards (CA 23,1967)
Germany Norm (DIN 4150,1999) Residential buildings
Relatively more sensitive buildings
The South African mudhouse case study
A study was conducted at an anonymous coal mine (Mine) following a complaint from the property owner. The Mine is an open cast thermal coal mine located approximately 30 km east of Middelburg in the Mpumalanga province of South Africa. The houses assessed was a homestead compound located at a horizontal distance of 5.26 km from the mine boundary. The Mine required that a structural integrity assessment and blast monitoring be conducted for the households that launched complaints about alleged blast-induced damages to their properties. The first phase of the study was to conduct a structural integrity assessment to establish the extent and nature of the damage and determine the likely cause of the cracks. The assessment of the property commenced on 13 May 2022 and was completed on 16 May 2022. The results from the structural assessment, census survey, predictive assessment calculation, and engagement with the house owners led to the following facts being drawn:
➤ All three units assessed were residential houses.
➤ The units had well defined vertical cracks.
➤ The units were made up of mud bricks and wood, coated with a thin layer of cement.
➤ Major cracks were on the load bearing lintels and vertical poles.
➤ Major failure occurred between the load bearing lintels and vertical poles.
➤ Weights placed on the roof introduce load and vibration on the structure.
➤ Trapped water moisture on the wall was evident.
➤ The houses were approximately 5.26 km from the mine boundary.
➤ The houses were more than 70 years old.
➤ The mine was using electronic delay detonators on single hole firing timing configurations.
➤ The predictive assessment indicated a seismicity of 0.4 mm/s, which was unlikely to cause damage based on the international and local standards.
A study was conducted following the cracks at the house, which follow a well-defined pattern. There were general vertical cracks. Figures 1 to 3 show the original pictures taken during the assessment, which show the vertical cracks and wooden lintels’ point of failure. Figure 4 shows trapped moisture in the wall and the weights on top of the roof. These weights are meant to stabilise the roof during experiences of wind. However, they introduce more loads on the wall and vibration during windy days. In the same picture, the wet wall can be observed, which is due to moisture. This moisture causes the mud bricks and the wood to expand. When
The blast-induced noise and ground vibration structural and human response
it shrinks as it dries, it creates voids and cracks that continuously expand under the natural origins.
The main points of weakness where major cracks were found are at the wood-cement contacts on wooden lintels and wooden poles. The wooden lintels and wooden poles are meant to relieve the loadbearing wall of the stress, however, since the wood expands more when absorbing water and it shrinks back to its origin the crack remains and creates a plain of weakness.
In summary, the study revealed that the structural design of the mud houses consists of mud bricks, wooden poles, and congregated iron sheets. Loose boulders and weights are often placed on the roof to stabilise the congregated iron sheets. The study further revealed that the standard wooden pole-mudbrick interface forms a plane of weakness. The plane of weakness is due to the weak bond between wood and mud. The study further revealed that the cement coating of the mud brick house traps moisture, which causes cracks. Another finding was that the loose boulders that are often placed on the roof exacerbate the impact on the structure and annoyance to the people.
The recent MCOP recognises that there could be houses not built according to engineering standards with structural integrity that is highly compromised. In addressing this issue, the guidelines use the principle of ‘who came first’, which means that the mine must put measures in place to ensure that structures that existed prior to the commencement of blasting operations are protected against the risks emanating from blasting operations. It further proposes that, where new structures are built close to the mine boundary after mining operations have commenced, these structures must be of a design that enables the structures to withstand the prescribed safety limits without sustaining undue damage. The mudhouse assessed was 70 years old and ‘came first’. This suggests that, irrespective of its structural integrity, the mine must ensure that its activities do not act as a catalyst to its further deterioration or subsequent damage.
Blast design parameters and predictive assessment
The blast parameters were obtained from the mine. The maximum parameters were used to create a worst-case scenario. The blast design parameters were assessed against the typical surface mine design parameters defined in the industry as the rules of thumb (RoT). The rule of thumb is an empirical standard, a guideline or norm. It is a general or approximate principle, procedure or rule based on experience or practice. The rules of thumb’s primary roles are to provide the perspective required to ensure practical concepts and designs and to facilitate in finding pragmatic solutions for operating problems. Table 4 shows the actual Mine blast parameters. Table 5 shows the typical blast parameters based on the RoT compared to the actual blast parameters at the coal mine.
Table 5
Figure 1—Vertical cracks with crack monitors installed
Figure 2—Vertical cracks at wood lintels running straight down to the floor
Figure 3—Vertical cracks between the vertical poles and major failure in between
Figure 4—Moisture on the wall and heavy loose material on the roof introducing load and vibration
The blast-induced noise and ground vibration structural and human response
Table 5b
Rule of thumb (test) for the Mine blast design
Predictive risk assessment for blast-induced ground vibration
This section is a quantitative approach to further assess the likelihood of high seismicity reaching the Mnguni site from the Mine blasting activities. Extensive research by the USBM since 1942 has shown that the variation of ground vibrations from surface mines depends on the distance and the quantity of explosives as defined by the following equation:
Where:
PPV, is the forecast peak amplitude or peak particle velocity. R is the radial distance (along the surface) to the seismograph. W is the mass of charge per delay in kg. The factor defines the scaled distance.
The constants a and b are site-specific constants that are a function of the transmission properties of the rock mass.
This study used standard constants a and b of 0.800 and 1.600 for a and b, respectively, to estimate the PPV’s safety circles regarding the structure. The aforementioned equation generated predictive seismicity based on the Mine blast parameters as a worstcase scenario. The results in Table 6 show that the seismicity from the mine boundary to the homestead, based on the current system used, would be 0.4 mm/s. This is below the normal unit trigger level of 1.2 mm/s. The human detectable threshold is reached at 3,400 m from the blast. The absolute minimal seismicity is at 7,000 m from the blast.
Table 6
Table 7
Records for July 2022
Actual results
Table 7 shows the actual results for July. The maximum seismicity recorded was 0.15 mm/s. This was below the humanly detectable levels. The maximum noise level detected was 121 dB. This was below the threshold of 128 dB (not more than 10% of the results should exceed this figure) indicated in the guideline used during the study. However, this is above the threshold of 120 dB (not more than 10% of the results should exceed this figure) provided by the current guidelines. The results suggest that the maximum seismicity of 0.15 mm/s is below the perceptible vibrations obtained from daily home activities such as walking, jumping, and door slamming, which produce 0.8 mm/s, 7.1 mm/s, and 12.7 mm/s, respectively. The blast-induced seismicity is therefore not likely to have caused any annoyance or damage.
The results indicated a maximum of 123 dB and an average of 121 dB from five (5) events recorded. According to Yan et al. (2017), the rattling of windows and ornaments is likely to occur when airblast frequencies match the natural frequencies of structures, which is likely to occur at 120 dB. Based on these results, it can therefore be concluded that the noise is more likely to be the cause of damage than seismicity.
Summary of the seismicity results
Figures 5 and 6 show the graphical representation of the seismicity and noise results, respectively.
South African adopted guidelines for the blast-induced noise and seismicity
The South African-adopted safe limits guidelines for noise and seismicity, are shown in Tables 8 and 9. The safe limits for noise are expressed in a robotic format where green means safe; yellow means caution; and red means that safe limits are exceeded.
The safe limits of the blast-induced seismicity for different structures are shown in Table 9. These guidelines are adopted from the USBM criteria. The mudhouse is rated at 6 mm/s. These limits are based on the ground peak particle velocity and frequency and do not consider the individual structural and human response.
The blast-induced noise and ground vibration structural and human response
Table 8
South African guidelines for noise level safe limits in a robotic format
Noise level (dB) Noise level pressure (kPa)
100
110 0,002 0,006
128 0,05
134 0,1
135-169 0,1-6,3
170 6,3
Perception / resulting consequence
• Barely noticeable
• Readily acceptable
• Currently acceptable by South African authorities that damage will not occur
• Currently acceptable by South African authorities that damage will not occur
• Poorly mounted pictures will fall
• Rattling of objects on shelves/display units potentially falling
• High likelihood to break windows
• Will break a well-mounted window
6—Blast-induced
Shortfalls in the structural response and set limits
The currently used safe-limit criteria for ground vibration, which are all based on the PPV and frequency of the ground vibrations, fail in many situations (ISEE, 2020). The safety limit criteria make no distinction for the structure's type, age, or stress history, all of which considerably affect the safety limits (Mahmoud, 2014). A significant drawback is also in the safe limit criteria itself. The currently adopted criteria were obtained by only correlating the structural damage to the intensity of the ground vibration. However, a safe limit criterion against ground-born vibrations due to blasting should be based on the structure vibration/response, not the ground vibration. The safe-level criterion should be applied to the PPV of the structural vibration due to blasting, not to the soil vibration. The vibration intensity depends on the soil-structure interaction that determines the structure responses to the ground excitation
Allowable frequency of exposure for structures
• No limit
• Reduce structural exposure
• Not more than 10% of measurements should exceed this value
• No measurement should exceed this value outside of the mining boundaries
• No measurement should exceed this value
• No measurement should exceed this value
Table 9
South African guidelines for the blast-induced seismicity safe limits
Structure type
Ground vibration safe limit (mm/s) National roads / tar roads
General house of proper construction 25 (USBM criteria)
Informal settlements 12.5 (USBM criteria)
Rural building - mud houses 6 (USBM criteria)
(Sayed-Ahmed, Naji, 2006). A ground vibration frequency of 40% (or more) greater than the fundamental frequency of the structure introduces a structure PPV that is less than the PPV of the ground vibration (Altunışık et al., 2021). On the other hand, a ground vibration with a frequency below the fundamental frequency of the structure causes the structure to vibrate at least as much as the ground.
If the ground vibration frequency is close to the structural natural frequency, a state of resonance may be generated, and the PPV of the structure will increase considerably beyond the PPV of the ground vibration. This phenomenon is disregarded in all the currently adopted safe limit criteria against ground-born vibrations due to subsurface blasting.
Low-rise buildings have a natural frequency of 4~12 Hz (Siskind, 1980). However, the structures and their parts (floor and walls) respond differently to ground vibration as they have different natural frequencies. The natural frequencies are 12 HZ~20 Hz for interior wall horizontal vibrations and 8 HZ~30 Hz for floor vertical vibrations (Siskind, 1980). Mid-wall vibrations cause residential buildings to rattle, making vibration more noticeable and aggravating human response to annoyance from ground vibration (Siskind, 1980). It is difficult, if not impossible, to follow a uniform vibration standard to reduce the human perception of vibration due to subsurface blasting (Baliktsis, 2001). Scientists and engineers
Figure 5—Boy Mnguni station PPV graph
Figure
acoustic level Graph (dB)
The blast-induced noise and ground vibration structural and human response
around the world have challenged the current safe limits, which are based on threshold/structure damage prevention. Svinkin (2004) proposed an application of an amplification factor ranging between 2 and 4.5 to the soil PPV in the frequencies range of 4 Hz to 30 Hz as a modification to these criteria to consider the structure’s resonance effect. Dowding et al. (2018) also agreed with the notion of the limitations in the current safe limits. The challenges in the safe limit criteria for structures get even more exaggerated for the structurally even weaker South African mudhouse structure. There is a need to investigate the South African-based mudhouse safety limit to ensure maximum protection of the citizens. The combination of engineering and administrative means could help solve the current problem, which will likely cause tension between the miners and the mudhouse homeowners. The South African law puts the safety of citizens first regarding mining hazards. It does not prescribe the details on how. It places the responsibility on the mine to ensure that its activities will not put the lives of the citizens in danger. The new MCOP guidelines put emphasis on the effective communication between the mine and the communities as far as blast notifications are concerned. This helps to manage the psychological impact likely to be caused by sudden unexpected blast-induced noise and seismicity.
The South African legal provision for the safety of persons staying in close proximity to the mines
The results from this study help guide the future areas of development in terms of the policy and practice. The results suggest that the DMPR-recommended safe limits should, for all purposes, be used as a guideline and use the risk assessment to establish the actual safe limits based on the prevailing conditions on the ground. A practical site-specific risk assessment (RA), code of practice (COP) and standard operating procedures (SOPs) will help to ensure that the mine permit holders operate in harmony with their neighbouring communities and in compliance with the law.
The South African Mine Health and Safety Act, (MHSA) of 1996 (Department of Mineral Resources, 2020), makes provisions in the interest of safety for the people not working at the mine who may be affected by the activities at the mine. Section 5(2) of the MHSA provides that, as far as reasonably practicable, every employer must identify relevant hazards and assess the risk to which persons who are not employees are exposed. It further requires the employer to ensure that persons who are not employees, but who may be affected by the activities at the mine, are not exposed to any hazard to their health and safety. According to the MHSA Regulation 4.16(2), surface structures within 500 m of blasting must be protected. The DRME directive released on 27 February 2020 requires that all opencast mines in Mpumalanga, operating within close proximity to the communities (within 500 m–2000 m) must ensure that structures be protected. The Government Gazette issued on 2 August 2024 mandated that all opencast mines operating within a 2,000 m proximity to the communities conduct a structural integrity survey of all the affected structures or buildings, effective from 1November 2024. The mudhouse homestead investigated in this study was situated at a distance of 5,260 m from the mine. This distance falls outside of the distance for which the law demands the risk assessment to be done prior to blast. The homeowner complained that the blasting activities were damaging his properties. The mine argued that the houses are situated far away, hence no pre-blast structural assessment was done, and no risk assessment or consultation was done. The DMR on the other hand, as the regulator, took the host community complaints seriously, however, lacked the appropriate standards and law that could be used when issuing judgements. Due to these challenges,
the exploitation of natural resources in South African has led to a variety of problems within host communities. In recent times, South Africa has witnessed an emergence of a disturbing trend by host communities (Seth, 2021). Such a reaction from the South African communities is not different from other host communities worldwide. Most mining companies are now resorting to relocating communities to pave the way for open-cast mining activities (Seth, 2021).
Recommendations
A hazard identification and risk assessment (HIRA) approach is recommended to address the South African mudhouse challenges. The HIRA is a standard method used in the South African mining industry. This method involves the process of identifying the relevant hazards and controls being applied to all activities that will be performed. The hierarchy of controls must be introduced to enhance the effectiveness of the controls in addressing the identified risk. The effectiveness of the controls in terms of risk elimination, substitution, and isolation must be prioritised. Engineering and administrative controls are used as key risk mitigation measures. Zero tolerance in terms of mudhouse structural damage and human annoyance must be applied. The safety limits are to be guided by the human and structural response to blast-induced noise and seismicity. The actual structural elements and the condition of the people living in the properties must be factored.
Elimination of the risk at source
An ideal solution is to eliminate the hazard or risk whenever it is possible to do so. However, elimination can be difficult to achieve due to costs involved or impossible due to technical reasons. The necessity for blasting in highly environmentally sensitive areas must first be established. Overburden may sometimes be stripped using mechanical methods rather than blasting. However, in most cases, blasting will be the only viable mining method.
Substitution
This solution suggested is that all the mudhouses, within a distance from the mine where structural and human response indicate a significant risk, would be replaced with stronger structures. Replacement of the mudhouses may be impractical to implement from a cost point of view; this may throw marginal mines out of business.
Isolation
The creation of a pre-split line in the direction of the sensitive structures creates a barrier between the active mining blocks and the sensitive structures. This significantly reduces the seismicity. The actual site seismicity transmission properties can be established by placing seismicity monitors on either side of the pre-split to assess the efficiency of the pre-split as a seismicity proof. The noise isolation factor can be achieved through effecting stemming that reduces the wasted energy component during blasting.
Engineering controls
Both blast-induced noise and ground vibration are highly dependent on the number of explosives used per an 8 milliseconds delay. An amount of charge mass per delay that would reduce the safety circles must be opted. Electronic delay detonators allow for a single hole or explosive deck firing. This results in a highly reduced charge mass per delay compared to the pyrotechnic methods. The engineering controls should include the types of blasting products and blast design systems that generate minimal noise and seismicity. These controls must be considered, and the site-specific results should be recorded.
The blast-induced noise and ground vibration structural and human response
Administrative controls
The administrative control should include the SOP with respect to blasting near mudhouses. A review, development and implementation of policy, and legislative measures to address the blasting impact on humans and structures around the mines are recommended. This is already being done, but it is further recommended that the administrative measures cover both technical and psychological aspects of the defined problem focused more on mudhouses as a weakest structure. Effective community engagement must be developed, implemented, and maintained.
Conclusion
The blast-induced seismic and noise impact on South African mudhouses has been explored in this paper. This paper critically evaluated the currently adopted safe limit criterion used in South Africa against the international standards such as those used in Australia, China, Switzerland, and the USA. The maximum seismicity of 0.15 mm/s obtained during the study was found to be below the perceptible vibrations generated during the daily home activities such as walking, jumping, and door slamming, which produce 0.8 mm/s, 7.1 mm/s, and 12.7 mm/s, respectively. This was used to eliminate seismicity as a likely cause for any annoyance and/ or damage. The maximum noise of 123 dB and an average of 121 dB from five (5) events recorded suggested that the noise was a more likely cause of annoyance and/or damage.
The study identified the gaps in the current regulatory instruments. It established that the current safe limit criterion focus on the general structural damage with little regard to human impact and response. A new approach is proposed based on relating the safe limits to the structural and human response. The results from this study will help in the development of a policy for better regulating the environmental impact emanating from blasting activities from mines. A mudhouse is the weakest residential structure. Addressing the challenges faced by the mudhouse dwellers could help resolve other related challenges.
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Website: http://www.saimm.co.za
22-25 September 2026 — XIX International Society for Mine Surveying Congress 2026
Century City, Cape Town
Contact: Gugu Charlie
Tel: 011 538-0238
E-mail: gugu@saimm.co.za
Website: http://www.saimm.co.za
29-30 September 2026 — 7TH Young Professionals Conference 2026
Mintek, Randburg, Johannesburg
Contact: Gugu Charlie
Tel: 011 538-0238
E-mail: gugu@saimm.co.za
Website: http://www.saimm.co.za
18-22 October 2026 — XXXII International Mineral Processing Congress 2026
Cape Town, South Africa
Contact: Camielah Jardine
Tel: 011 538-0237
E-mail: camielah@saimm.co.za
Website: http://www.saimm.co.za
4-6 November 2026 — Southern African Mine Water Conference 2026
Let’s Connect
Mintek, Randburg, Johannesburg
Contact: Gugu Charlie
Tel: 011 538-0238
E-mail: gugu@saimm.co.za
Website: http://www.saimm.co.za
Company affiliates
The following organizations have been admitted to the Institute as Company Affiliates
acQuire Technology Solutions
AECI Mining Chemicals, a division of AECI Mining Ltd
African Pegmatite
Allied Furnace Consultants
AMIRA International Africa (Pty) Ltd
Anglo American Platinum Corporation
Anglogold Ashanti Ltd
Anton Paar Southern Africa
Arcus Gibb (Pty) Ltd
Becker Mining (Pty) Ltd
Bluhm Burton Engineering Pty Ltd
BSI Group South Africa
Buraaq mining Services (Pty) Ltd
Caledonia Mining South Africa
Carbocraft (Pty) Ltd
Castle Lead Works
CIGroup ACE Pty Ltd
DDP Specialty Products South Africa (Pty) Ltd
Digby Wells and Associates
E2 Test
EHL Consulting Engineers (Pty) Ltd
EKATO South Africa
Elbroc Mining Products (Pty) Ltd
Elderberry Trading
Epiroc South Africa (Pty) Ltd
Ex Mente Technologies (Pty) Ltd
Exxaro Resources Limited
FLSmidth Minerals (Pty) Ltd
GHH Mining Machines (Pty) Ltd
Geobrugg Southern Africa (Pty) Ltd
Glencore
Gravitas Minerals (Pty) Ltd
Hatch (Pty) Ltd
Herrenknecht AG
Impala Platinum Holdings Limited
IMS Engineering (Pty) Ltd
Ingwenya Mineral Processing
Ivanhoe Mines SA
M84 Geotech Pty Ltd
Malvern Panalytical (Pty) Ltd
Maptek (Pty) Ltd
Mech-Industries (Pty) Ltd
Micromine Africa (Pty) Ltd
Minearc South Africa (Pty) Ltd
Minerals Council of South Africa
MineRP Holding (Pty) Ltd
Mining Projection Concepts (Pty) Ltd
Mintek
MLB Investments CC
Modular Mining Systems Africa (Pty) Ltd
Murray & Roberts Cementation (Pty) Ltd
Optron (Pty) Ltd
Paterson & Cooke Consulting Engineers (Pty) Ltd
Pump and Abrasion Technologies (Pty) Ltd
Redpath Mining (South Africa) (Pty) Ltd
Rosond (Pty) Ltd
Roytec Global (Pty) Ltd
Rustenburg Platinum Mines Limited - Union
Salene Mining (Pty) Ltd
Schauenburg (Pty) Ltd
Sebotka (Pty) Ltd
SENET (Pty) Ltd
Sibanye Gold Limited
Solenis
Sound Mining Solution (Pty) Ltd
SRK Consulting SA (Pty) Ltd
Sulzer Pumps (South Africa) (Pty) Ltd
Tomra (Pty) Ltd
Trans-Caledon Tunnel Authority
Ukwazi Mining Solutions (Pty) Ltd
VBKOM Consulting Engineers
Weir Minerals Africa
Zutari (Pty) Ltd
LET’S CONNECT SOUTHERN AFRICAN MINE WATER CONFERENCE 2026
VENUE – JOHANNESBURG
4 - NOVEMBER 2026 – TECHNICAL WORKSHOPS
5 - 6 NOVEMBER 2026 – TECHNICAL CONFERENCE
6 - NOVEMBER 2026 – TECHNICAL VISIT
In Partnership:
ABOUT THE CONFERENCE
The Southern African Institute of Mining and Metallurgy (SAIMM), in collaboration with the International Mine Water Association (IMWA), the Mine Water Division of the Water Institute of Southern Africa (WISA-MWD) and Mintek, warmly invites you to the Southern African Mine Water Conference 2026, a premier gathering where science, technology – and sustainability intersect.
Guided by the theme “Let’s Connect,” this conference is more than an event – it’s a movement to bridge disciplines, foster innovation – and build resilient solutions for mine water management. Attendees will explore a wide spectrum of topics, from the complexity of mine water geochemistry to the transformative power of AI-driven modelling and simulation.
Discover how mining-influenced water (MIW) can be repurposed through circularity and value recovery and gain insights into the latest advancements in water treatment technologies and microbial processes that are reshaping environmental stewardship.
Whether you are a researcher, engineer, policymaker, or industry practitioner, this is your chance to engage with cutting-edge developments, share your expertise – and help shape a more connected future for mine water innovation.
CONFERENCE TOPICS
Explore cutting-edge developments and share insights on:
• Mine water geochemistry
• Utilisation of mining-influenced water (MIW), circularity, and recovery of value products
• Modelling and simulation
• Artificial Intelligence applications
• Water treatment technologies
• Microbial processes in mine water systems
CALL FOR PAPERS/PRESENTATIONS
Prospective authors are invited to submit short abstracts of not more than 500 words. Abstracts should consist of 4 paragraphs describing the presentation’s significance, the methods used, the key results and their application as well as implications.
Authors of accepted abstracts will be required to submit a full paper for peer review and publication in the conference proceedings. A presentation only option will be considered.
ECSA and SACNASP Validated CPD Activity Credits = 0.1 per hour attended
XIX 2026 International Society for Mine Surveying Congress
VENUE: CENTURY CITY, CAPE TOWN
22-24 SEPTEMBER 2026 – CONFERENCE
25 SEPTEMBER 2026 – TECHNICAL VISITS
Hosted by Institute of Mine Surveyors of Southern Africa and the International Society of Mine Surveying.
ABOUT THE CONGRESS
The International Society of Mine Surveyors (ISM) holds its congress every three years, uniting global mine surveying professionals. South Africa will host the XIX ISM Congress in 2026 in Cape Town, focusing on all aspects of mine surveying.
What is Mine Surveying?
A specialised field within mining science, mine surveying involves measurements, calculations, and mapping throughout the mining lifecycle, including:
• Planning and controlling mine operations for safety and efficiency.
• Evaluating mineral reserves and economic viability.
• Managing mineral rights and mining cartography.
• Assessing mining impacts on land and geology.
• Supporting environmental and rehabilitation efforts.
CONGRESS OBJECTIVES AND FOCUS AREAS
The 2026 Congress will showcase ISM’s six commissions and feature key topics such as:
• Mineral & Geology Studies – Understanding deposit structure and characteristics.
• Resource Assessment & Economics – Evaluating reserves and feasibility.
• Mineral Property Management – Handling acquisitions, sales, and leases.
• Mine Operations – Optimising planning and control.
• Rock & Ground Movements – Studying subsidence and mitigation.
• Environmental Rehabilitation – Ensuring responsible land restoration.
This global event will foster collaboration, innovation, and knowledge sharing, advancing the mine surveying profession.
