APRIL 2021 VOLUME 4 ISSUE 3
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On the Cusp of Change in Africa
Continuous Safety and Sustainability Diogo Craveiro, Vermeer Corporation, USA, provides an overview of the benefits of continuous surface mining methods.
Kunal Sawhney, Kalkine Group, Australia, examines the impact of COVID-19 on the African mining industry and how an increase in the adoption of electric vehicles and renewable energy could provide substantial opportunities for the continent.
Making the Difficult Choices Alek Duerksen, Emerson, USA, explains the difficulties of tailing disposal and provides suggestions for choosing the proper automated isolation valves for this service.
Back to Basics Gaurab Nakarmi, TSURUMI PUMP, Japan, addresses the importance of pump efficiency to the mining industry.
Automation: Not One-Size-Fits All Brendon Cullen, RCT, Australia, examines the key factors driving technology decision-making in the mining industry.
The Power of Monitoring and Modelling Dr James Counter, Nalco Water, Australia, outlines how important the ability to monitor and model water composition is for mitigating scale.
Kesavan Vijayanand, TAKRAF, India, outlines the possible design features and challenges that may need to be overcome when designing an overland conveyor.
Success Rides on the Rack Tim A. Schultz, Caterpillar Inc., USA, outlines how precision design, operating techniques, and proper maintenance are all key to getting the most life out of a swing rack.
Art Meets Science Paul Harrison and Todd Swinderman, Martin Engineering, USA, emphasise the importance of thinking long-term when developing a conveyor system in order to maximise safety and cost-efficiency.
Smarter, Safer, Sustainable Gary Robertson and Justin Johnson, MineWare, review the importance of the load and haul process and how it offers some significant opportunities to achieve better operational efficiencies.
Designing to Overcome
Blasters Innovate Tomorrow’s Mining Ralf Hennecke, BME, South Africa, explores how integrating technology within drill and blast operations can help foster efficient and responsible mining.
ON THE COVER
APRIL 2021 VOLUME 4 ISSUE 3
This month’s cover shows part of an MMD Semi-Mobile Sizer Station, relocated a few kilometres closer to the working face to optimise the cost-effectiveness of a short haul truck-and-shovel operation. The bespoke 5500 tph station is relocated in four modules (feeder/hopper, sizer, conveyor, and control) by a 500 t capacity MMD Atlas transporter crawler. The Sizer Station and transporter are integral to the mine’s expansion, helping the operator reach production rates of 40 000 tpd of coal.
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n the past, the idea of space mining has focused on exploiting the rich resources of near-Earth asteroids. More recently, the focus has shifted to in-situ resource utilisation (ISRU) in support of space exploration, especially in the context of NASA’s Artemis Program to return astronauts to the Moon by 2024 and establish a sustainable presence.1 For example, in October 2020, NASA selected Houston-based company, Intuitive Machines, to land an ice-mining drill on the Moon’s south pole in 2022.2 Meanwhile, China’s Chang’e-5 orbiter successfully delivered lunar materials to Earth in December 2020, including drilled core samples.3 The old dream of asteroid mining also perhaps came a step closer last year, with the successful return of a sample from the asteroid Ryugu by Japan’s Hyabusa2 spacecraft.4 However, the international legal framework governing the exploitation of space resources is unclear, untested and, as a result, keenly contested. This creates uncertainty over whether a private company would, ultimately, be entitled to own and commercialise the resources that it extracts, and so potentially undermines investor confidence. The key legal instruments addressing space resources, which were drawn up at the height of the Cold War and long before commercial exploitation was a realistic possibility, are: (i) the 1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (the Outer Space Treaty); and (ii) the 1979 Agreement Governing the Activities of States on the Moon and Other Celestial Bodies (the Moon Agreement). Whilst, the Outer Space Treaty has been widely ratified, the Moon Agreement has not. This is significant because the Outer Space Treaty addresses the issue of space resources less clearly than the Moon Agreement, and arguably imposes fewer limitations. Article I of the Outer Space Treaty states that “[o]uter space, including the Moon and other celestial bodies, shall be free for exploration and use by all States”, and Article II states that outer space is “not subject to national appropriation” by States. It is therefore clear that a State cannot lay claim to objects in outer space. But, what is less clear, and keenly debated, is whether this non-appropriation principle would prevent a private party from owning resources they extract in space. Among other things, if a State cannot appropriate outer space objects, it is questionable whether it could validate a private party’s claim to any space resources. Notably, Article 11 of the Moon Agreement states that the Moon and its natural resources (and other objects in the Solar System) are the “common heritage of mankind”, and cannot become the property of inter alia, a non-governmental entity, or natural person. The concept of the “common heritage of mankind” is a contentious one, and historically the US in particular has rejected it. In April 2020, the Trump administration issued Executive Order 13914, which rejects the Moon Agreement and asserts the right of Americans to engage in commercial exploration of space resources. More recently, the US perspective has been reflected in a series of Artemis Accords that NASA has entered with its international partners in the Artemis Program, including the UK. The accords signed with the UK include a brief affirmation that the “the extraction of space resources does not inherently constitute national appropriate under Article II of the Outer Space Treaty.” However, this form of bilateral governmental agreement is a far cry from an established legal regime that firmly establishes private property rights in space resources on a global basis. There have been proposals made for such a regime, including the “Building Blocks for the Development of an International Framework on Space Resource Activities”, adopted in November 2019 by the Hague International Space Resources Governance Working Group.5 These are valuable discussions and a necessary prelude to a fully-fledged legal regime. In the meantime, however, the technology to utilise space resources is developing apace, which means that the pressure to resolve these long-contested issues – one way or another – will continue to build. A comprehensive list of this guest comment’s references can be found on the Global Mining Review wesbite: https://www.globalminingreview.com/special-reports/.
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SOUTH AMERICA Anglo American secures renewable energy for South American operations
nglo American has delivered on its commitment to source 100% renewable energy for all its operations in Brazil, Chile, and Peru. Having already secured renewable energy to meet all its power requirements for its iron ore and nickel operations in
Brazil from 2022, and for its copper operations in Chile from 2021, Anglo American has now signed an agreement with Engie Energía Perú to provide 100% renewable energy for the Quellaveco copper operation in Peru. It is expected to begin production in 2022.
BRAZIL Vale starts Vargem Grande Complex filtration plant operation
ale has gradually started operation of the tailings filtration plant located at the Vargem Grande Complex, the first of four filtration plants to be operated in Vale’s sites in Minas Gerais, totalling US$2.3 billion in investments between 2020 and 2024. In addition to reducing the dependence on dams, the start-up will allow an improvement in the average quality of Vale’s product portfolio with the use of wet processing on the site. In the filtration process, the existing water in the iron ore tailings is minimised, allowing most of the material to be stacked in a solid state, thus reducing dependence on dams. Still in 2021, Vale expects to start-up the first filtration plant in the Itabira Complex. Throughout 2022, the second filtration plant at the Itabira Complex
and the first at the Brucutu site will start operating. The four tailings filtration plants will serve beneficiation plants that have a total capacity to process 64 million tpy of iron ore. The addition of 4 million tpy of production will take place from 3Q21 along with the start-up of the Maravilhas III dam, which is in its final stage of construction and will receive the slime from the plant, equivalent to approximately 30% of the total tailings generated from this operation. The start-up of tailings’ filtration operations in Vargem Grande is another step in the process of stabilising iron ore production, on the way to resuming a 400 million tpy production capacity by the end of 2022.
GLOBAL CMOC and IXM join RCS Global Group’s Better Mining programme
hina Molybdenum Co., Ltd (CMOC) and its Geneva-based trading arm, IXM, have announced that they will join Better Mining as supporters. The duo joins a growing list of businesses who have publicly committed to support the ground-breaking mineral agnostic upstream assurance and impact programme. Implemented by the RCS Global Group, the programme is focused on artisanal and small scale mining (ASM). An industry wide programme, Better Mining is active across 27 cobalt, copper and 3TG ASM mine sites, with replicability to mica and other ASM mined materials worldwide. The programme monitors and supports the improvement of conditions on and around ASM sites through its world-first data platform. The demonstrable and continuous improvement the programme generates in an otherwise challenging sector has resulted in a growing list of global corporations at all tiers of the global raw material value chain supporting Better Mining,
including several major global ICT and auto brands like Volvo Cars and Intel. In 2020, Better Mining generated data on 1000+ incidents across seven risk areas, and subsequently delivered 480 corrective action recommendations. Of these 480 corrective actions, 72% have either been, or are in the process of being, implemented. The programme is expanding at pace in collaboration with the Responsible Minerals Initiative, an organisation addressing responsible mineral sourcing issues in various industries’ global supply chains that is over 400 companies strong. As an official Better Mining supporter, CMOC will have access to Better Mining’s world-first technology enabled ASM data streams. These deliver product traceability and on-site monitoring data across the ASM sites covered by the programme. CMOC will also have the opportunity to quickly scale up its engagement with the programme in the future and adopt its use for proactive risk management and impact generation at its industrial mine sites. GLOBal mining review // April 2021
WORLD NEWS Diary Dates CIM Virtual Convention & EXPO 03 – 06 May 2021 VIRTUAL EVENT https://convention.cim.org Mines and Money Online Roadshow 06, 13, 18 May 2021 VIRTUAL EVENT: APAC, EMEA, Americas www.minesandmoney.com/online/ roadshow.php Euro Mine Connect 2021 01 – 03 June 2021 VIRTUAL EVENT www.euromineconnect.com Mines and METS 2021 07 – 09 June 2021 VIRTUAL EVENT www.minesandmets.com Elko Mining 2021 07 – 11 June 2021 Elko, Nevada, USA www.exploreelko.com/major_events/ elko_mining_expo/index.php MINExpo INTERNATIONAL 2021 13 – 15 September 2021 Las Vegas, Nevada, USA www.minexpo.com AIMEX 2021 16 – 18 November 2021 Sydney, New South Wales, Australia www.aimex.com.au
To stay informed about the status of industry events and any potential cancellations of events due to COVID-19, visit Global Mining Review’s events page: www.globalminingreview.com/events
April 2021 // global mining review
SCANDANAVIA Trafikverket, LKAB, and Bane Nor running
tests on Ore Railway
rafikverket (the Swedish Transport Administration), together with LKAB and Bane Nor, is conducting tests on the Swedish and Norwegian sections of the Ore Railway to enable heavier transports in future. Therefore, the axle load for ore cars is being increased from 30 t to 31 t. Testing will be carried out on both the Swedish and Norwegian stretches of the railway that runs between Kiruna and Narvik (Malmbanan and Ofotbanan). For some time, testing has also been under way on the southern section of the line, between Malmberget and Luleå. In business and industry there is a great demand for increased capacity on the Ore Railway. By upgrading the railway, more freight can be hauled without increasing the number of trains operating on the line. The tests are part of a forward-thinking strategy, the ambition of which is to be able in future to operate trains with an axle load of 32.5 t along the entire Ore Railway. In 2020, LKAB hauled over 34 million t on the Ore Railway, mainly iron ore from the mines in the orefields, to the ports in Luleå and Narvik for onward shipment to customers. The mining company now wishes to increase production further and, with such great volumes, even a few percentage points in capacity increase can have a significant impact. LKAB has begun the transition to carbon-dioxide-free production. Hydrogen will be used to reduce oxygen from the iron ore at the mine sites, which means that the resulting sponge iron that is to be hauled by train will have a higher volumetric weight.
UK Pensana Rare Earths to establish sustainable supply of
critical rare earths
ensana Plc has announced that the company has adopted a business plan to seek to establish, subject to funding, a world-class, independent, and sustainable supply chain of the rare earth metals vital for electric vehicles, wind turbines, and other strategic industries. This involves plans to establish the world’s first sustainable rare earth separation facility at the ‘plug and play’ Saltend Chemicals Park in Humber, UK. With a target production of approximately 12 500 tpd of rare earth oxides, including 4500 t of magnet metal rare earth oxides, it would represent approximately 5% of 2025 projected world demand. The plans to establish the Saltend rare earth separation facility will make it the world’s first major separation facility established in over a decade, as well as one of only three major producers located outside China. The planned US$125 million facility would create over 100 direct jobs processing purified rare earth sulfates, which would be imported from the company’s state-of-the-art Longonjo mine in Angola. Benefitting from the recently awarded Humber Freeport status, Saltend has the potential to bring high value manufacturing jobs back to the UK and, through Pensana’s plans, could become one of the world’s largest rare earth processing hubs, importing sustainably, globally sourced feedstock and processing it into valuable oxide and metal products for consumption by European original equipment manufacturers and beyond.
USA Lexington Gold completes Phase 1 drill programme
exington Gold, a gold exploration and development company with four projects in North and South Carolina, USA, has announced the completion of its Phase 1 drill programme at the Jones-Keystone-Loflin (JKL) Project. The JKL Project was selected as the first project for drilling due to its geological similarities with the third party Haile Mine and its promising historical drill hole intersections.
Lexington Gold’s four-project portfolio covers a combined area of approximately 1675 acres in the highly prospective Carolina Super Terrane (CST) located in North and South Carolina, USA. The CST has seen significant historic gold production and is host to a number of multi-million-ounce mines operated by large scale companies, including the Haile Mine operated by OceanaGold Corp.
PORTUGAL Savannah Resources announces Mina do Barroso EIA progress
avannah Resources has announced that, following its review, Agência Portuguesa do Ambiente (APA), the Portuguese environmental regulator, has declared the Mina do Barroso Lithium Project environmental impact assessment (EIA) to be in conformity with its requirements for the content of the EIA. The Mina do Barroso development plan is based on Savannah’s ‘Green and Smart Mining’ concept, with a strong focus on the efficient use of energy, materials and water, in order to reduce the environmental footprint of the life cycles of mineral-based products.
The project’s design will involve the investment of over €15 million of initial capital costs into measures to either eliminate or reduce potential social and environmental impacts. €110 million will be invested in developing the project locally, which will bring a series of benefits to the Boticas region and will create approximately 215 direct jobs and between 500 and 600 indirect jobs to support the project. The EIA will now progress to the next stages of the approval process, this being a public consultation and a detailed review by the APA’s Evaluation Committee, which take place simultaneously.
GLOBAL Mining3 and ENGIE combine to drive decarbonisation in mining
ining3, a leading research organisation in the global mining industry, and ENGIE, a global player in low-carbon energy and services, have announced the commencement of the Hydra Consortium. The Hydra Consortium is now actively working on validating the business case of utilising a hydrogen fuel cell-based powertrain for heavy-duty mobility within the mining sector. This will enable heavy-duty mining mobile equipment to run on renewable hydrogen, displacing diesel, and as such decarbonise the mining sector. To achieve this target, several workstreams will be executed, amongst others a pre-feasibility and engineering study of a powertrain and the renewable hydrogen value chain. This includes the designing, manufacturing, and testing of a 200 kW fuel cell plus battery powertrain prototype under mining conditions (altitude, dust, temperature, etc.). The test outcomes will provide valuable information to optimise the overarching design that could replace the traditional diesel powertrain.
In addition, the project will support government entities, in Chile and beyond, by establishing safety protocols for hydrogen use at scale within the mining industry, which will be critical for the successful deployment of this hydrogen solution. Finally, the project will complete the competitiveness analysis for validation of the business case, determining whether Consortium members could consider a scale-up of the solution. In August 2020, the Chilean Economic Development Agency was the first to support the project, by awarding it with CLP 252 million (the equivalent of €280 000) in government funding to Mining3 in partnership with CSIRO Chile. Since then, Mitsui & Co. (USA) Inc. and Thiess, both active in the mining sector, have provided additional support as part of their commitment to develop sustainable solutions for decarbonising the resources industry. Also, several technology companies are contributing, each within their areas of expertise: Ballard Power Systems will provide its fuel cell systems; Hexagon Purus will supply hydrogen storage systems; and Reborn Electric Motors will complete the systems integration. GLOBal mining review // April 2021
8 April 2021 // global mining review
Kunal Sawhney, Kalkine Group, Australia, examines the impact of COVID-19 on the African mining industry and how an increase in the adoption of electric vehicles and renewable energy could provide substantial opportunities for the continent.
ince the beginning of civilisation, human lives have been centred around minerals and with time, this dependence seems to have grown exponentially. The respectable antiquity of extracting and utilising minerals dates back more than 2.6 million years, making mining one of the earliest recorded activities globally. Africa is home to one of the most lucrative mineral-rich regions offering attractive opportunities for explorers, miners, and investors. The continent’s treasures include: precious minerals, such as diamond and gold; energy commodities, including coal; and base metals, such as copper, aluminium, cobalt, etc. The region is a major mining hub with mining activity being critical to social and economic development. The socio-economic development of the local inhabitants in Africa is deeply associated with the mining industry. The changing market dynamics and illegal artisanal mining have posed a major challenge to the mining industry. However, the pandemic and the recent gold price rally have sparked off a chain of new trends, favouring the transition to
technology-assisted mining in the continent where 60% of mining activity is associated with gold. In addition, the growing global surge towards the adoption of renewable energy and electric vehicles (EVs) is creating greater demand for the ethical and sustainable supply of battery metals, especially cobalt.
Mining synonymous with socio-economic development for the region Africa is heavily endowed with minerals and holds the world’s largest reserves of minerals including bauxite, cobalt, and gold. The continent hosts over 30% of global mineral reserves and currently produces over 60 metals. South Africa alone is estimated to hold non-energy mineral reserves worth US$2.4 trillion, making it one of the world’s richest mining jurisdictions on the planet. As per the World Gold Council, the African continent accounted for approximately 19% of global gold production in 2019 – with Ghana leading the pack with 142.4 t, followed by
global mining review // April 2021
South Africa with 118.2 t. Together, African nations, such as South Africa, Namibia, Zimbabwe, Angola and the Democratic Republic of the Congo (DRC), are amongst the leading producers of precious metals and diamonds. Africa holds 30% of the global diamond reserves; just two countries, namely DRC and Botswana, produce over 55% of the global production. The gold mining industry of South Africa is home to the Witwatersrand basin, which observed the largest gold rush globally during the 19th century. The basin still hosts some of the largest and deepest gold mines globally. Even in the base metals segment, the continent is extremely wealthy (especially the DRC and Zambia). With a boom in EVs and renewable energy, cobalt has become an indispensable commodity for which the demand is set to grow multi-fold in the upcoming years. The recent green stimulus and attractive incentive
Figure 1. The largest man-made hole in Africa, the Phalaborwa opencast mine. Source: Foture | Megapixl©.
programmes aim to boost the prospects of renewable energy and electric vehicles.
COVID-19: Driving the wave of autonomous and digital mining The COVID-19 pandemic severely disrupted the global commodity supply chain as quarantine restrictions and social distancing norms triggered the suspension of more than 1000 mining operations globally. While many mines suspended operations, some continued operating at lower rates in the absence of autonomous mining technologies at these mines sites. Several mining operations emerged as hotbeds for virus outbreaks, including the world’s deepest mining operation, AngloGold Ashanti’s Mponeng mine in South Africa. Roger Baxter, the CEO of the Mineral Council South Africa, predicted that mining production could slump by 8 – 10% in the country in 2020, due to the temporary suspension of mining operations in the wake of a nationwide lockdown. While the pandemic affected most mining operations, a few mines remained unaffected. One such example was Resolute Mining’s Syama gold mine, which is credited as being the world’s first fully autonomous gold mine. Located in the West African country of Mali, the Syama gold mine remained unfazed by the virus outbreak and continued to operate normally, enabling the gold producer to earn millions and maintain productivity in a time when gold prices rallied to record highs over US$2000/oz. The uncertainty over the scale of vaccination drives and the outbreak of the new COVID-19 strain 501.V2 has upped the possibilities of future disruptions in the African mining space. However, the pandemic could actually turn out to be a benefit to the industry, triggering an autonomous and technology-assisted mining trend across the continent.
Disruptive technology to rev up African mining operations While a global phenomenon to move towards automated, advanced and technology-equipped mining has been observed in recent years, it is often debated if the African mining industry Figure 2. Autonomous excavator and truck. Source: Zrrm97 | Megapixl©. is adequately prepared to embrace new age technologies. In a bid to enhance the potential sustainability of its operations, the African mining industry continues to adopt automation and electrification to minimise the energy costs of mining, making it more sustainable and safer in nature as an industry. New age mining technologies have never been more prescient than at the height of the global COVID-19 pandemic, when mines were forced to either suspend their operations or operate with limited Figure 3. Daily gold price chart as on 4 March 2021 (US$/oz) Source: Eikon Refinitiv. manpower.
10 April 2021 // global mining review
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It has become more pressing than before for the African mining industry to prioritise energy projects in order to stabilise and standardise the access to power of mine sites and their infrastructure projects. This promotes the industry to embrace new age technologies, such as: the internet of things, automated and autonomous mining, blockchain, geospatial data mapping, analytics, and artificial intelligence.
Power projects and autonomous mining to enhance mining productivity Advanced technologies would only be beneficial to a smaller extent if not complemented with the energy and power projects located across Africa. The adoption of digital technologies would increase the productivity of mining operations which have been severely impacted in recent years. The ore grade decline and the increasing depth of mining operations have pushed the cash cost to the bottom quartile. The higher cash cost minimises the margins, and thereby makes the operations more susceptible to commodity price fluctuations. The application of new technologies will ensure better safety for the African mining operations. The JSE and NYSE listed Goldfields owns the South Deep gold mine, the world’s largest gold mine by reserves (32.8 million oz), which was temporarily shut down due to coronavirus-related stoppages. The gold major had previously announced that autonomous underground loaders would be installed at the mine to enhance productivity, and the implementation of this decision appears to have been accelerated by the COVID-19 crisis. The company’s CEO, Nick Holland, said: “The COVID-19 crisis will undoubtedly help to accelerate the mechanisation, automation, and digitisation of the mining industry.” Another diversified miner, Anglo American, also recently installed a new automated drill at the Kumba Kolomela mining operations in the Northern Cape province of South Africa, allowing it to be operated remotely. While this implementation of autonomous drilling was the first of its kind in South Africa, many more are expected in the future. A strong pairing of human and machine will be critical to the future of mining operations. While digital technologies cannot be expected to be implemented in a short span, the transition of mining operations to an autonomous and digital future has begun.
Pandemic: An accidental boon for the African gold industry Almost 60% of the mining activities in Africa correspond to gold. The continent produces approximately 483 tpy of gold, which amounts to approximately 22% of global gold production. The continent’s major gold producers include: Ghana, South Africa, Sudan, Mali, and Burkina Faso. The recent rally in gold and precious metals has added fuel to the African gold industry. 2021 is expected to see recovery in broader economic situations, aiding the consumption demand of gold – especially in India and China. The rising demands of gold as a safe-haven asset during the COVID-19 situation have accelerated artisanal and small scale mining (ASM) activities in Africa. As the pandemic rattled the stock markets, investors embraced the precious metal as an essential investment to their portfolio, boosting the demand for the yellow metal. The gold price surged to its lifetime high and still trades over the US$1800 mark. ASM activities often operate under inhumane conditions and involve child labourers squeezing into narrow pits, non-professional mining activities, and the smuggling of precious metals for money laundering – used in the purchase of artilleries by narcotic dealers and warlords. The unregulated artisanal mining industry is used by national forces, foreign-backed militants, and local fighters to gain political control and resource identity.
ASM ingrained in the gold industry Approximately 20% of the world’s total supply of gold and diamond comes from the ASM sector. ASM operators focus on high value minerals – such as gold, diamonds, and gemstones – and are most active in the DRC, Ghana, Sierra Leone, Ethiopia, Tanzania, Zimbabwe, and Madagascar. As per the World Bank’s report in 2019, the Sub-Saharan African region is home to over 10 million artisanal and small scale miners, with an additional 60 million people reliant on the sector. The intensity of the ASM activities is significantly affected by the seasonal variation in the region, where most miners want to alleviate their poverty by complementing their farming income. In Western Africa, warlords and terrorist groups are known to force people into the artisanal and small scale mining. Also, there are many instances of conflict between people involved in large scale mining and artisanal mining. The formalisation of illicit mining practices, bringing ASM diggers under the legal umbrella, improving miners’ working conditions, and prohibiting child labour could bring reform in the industry. The formalisation will also reinforce income for the government, primarily through tax assessment and profit sharing.
The battery opportunity: impending scarcity of cobalt
Figure 4. Electric truck. Source: Kalkine Media Limited 2021 ©.
12 April 2021 // global mining review
Governments around the world have pledged to transition to a carbon neutral economy and have announced mega stimulus packages with a special focus on renewable energy and electric vehicles. In the past year, major economies – including the UK, France, Germany, Spain, and China – have either introduced or extended incentive programmes promoting the switch to EVs.
The US re-joining the Paris Agreement, Biden’s US$400 billion proposed federal investment in clean energy inputs, and the installation of 500 000 EV charging stations may push the demand for clean energy even further. The battery packs in EVs are manufactured using valuable battery metals – including: cobalt, lithium, nickel, manganese, and others – to maximise the energy density and the stability of the battery packs. The DRC supplies nearly 70% of all cobalt in the world. With the boom in EVs and renewable energy-based energy storage systems, cobalt has become an indispensable commodity of trade. According to the DRC’s ministry of mines, the country exported 38 815.63 t of cobalt in 1H20. Looking to the future, according to a World Bank report, the global demand for cobalt is expected to rise multi-fold to 644 000 t by 2050, on the back of the global transition to renewable energy and EVs.
Artisanal cobalt mining show signs of formalisation Numerous human rights groups have reported that ASM produces over 30% of the cobalt in the DRC. In order to formalise the ASM, the government of the DRC has been negotiating for large mining companies to come in and collaborate with the artisanal miners. The large mining companies would regulate the mining methods, bring in mine safety measures, and check for child labour. The DRC government has adopted a policy to assign or allocate land for ASM. This will ensure that the cobalt coming out from DRC is not trafficked, and that human rights violations have not been committed. The implications of ASM on health, safety, and environment are huge and need immediate attention from the government and concerned international bodies. The people involved in ASM do not have the proper training or skills required to carry out safe mining operations. Once the formalisation of ASM comes into existence and a common guideline is set, depending on the individual countries, it will be easier to implement environment, social, and governance (ESG) policy in the ASM sector.
Africa to address ESG concerns ESG considerations are taking notable prominence in decision-making processes across major funding organisations, such as banks and investment firms. The impact of the same is already visible across regions. For instance, Australian mining major Rio Tinto saw its top management reorganised after the Juukan Gorge crisis. Amid this scenario, African nations need to combat ESG shortcomings aggressively.
Conclusion When it comes to cobalt and gold, there lies a substantial opportunity for the DRC, Ghana, South Africa, and Africa as a whole. The continent needs to implement various measures, such as formalising the artisanal mining activities, in order to empower and safeguard individuals and improve the mining conditions. Taking these steps will help the continent to participate and spearhead the transition to EVs and renewable energy.
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t measures 2.8 m (17 ft) in diameter and weighs over 20 411 kg (45 000 lb). It is the often forgotten, less-visible workhorse of the electric rope shovel. Hundreds of thousands of kilograms are supported by this structure, which disperses the stress from every crowd motion, dipper hoist, and loading swing cycle of the upper works. While massive, the swing rack is a precisely engineered system, critical to the longevity of an electric rope shovel. Swing racks support the entire weight of the upper works, as well as absorb the reaction forces when digging material. Though steel is often thought to be rigid and immovable, in the mining industry even the most robust steel castings, such as a 20.4 t swing rack, can deform similarly to a spring plate in operation. The base of a swing rack design consists of two drive assemblies working in unison. Each assembly drives output pinions via a planetary dual-output final drive, forming a single part with multiple critical functions. Indeed, while most designed components serve a single purpose, a swing rack acts as both a gear and a bearing, whilst simultaneously supporting the
14 April 2021 // global mining review
entire weight of the massive upper works. It is a critical component to the electric rope shovel. Swing gearsets bear tremendous loading from the dual output gearboxes, able to revolve the full inertia of the 952 000 kg (2.1 million lb) of upper works in just under 12 seconds from a complete stop. With so much riding on the swing rack, electric rope shovel manufacturers painstakingly perfect the design and gearing precision. Premium quality gear design and manufacturing directly results in a longer system, and, therefore, a lower total cost of ownership.
Tight tolerances Historically, swing racks were multiple-piece assemblies, welded or bolted together in the field. Some designs included gear teeth as cast, while others were welded on. Since repeated shovel loading and unloading cycles induce fatigue stresses in components, every weld, bolted joint, and discrepancy in quality is at the mercy of the engineer’s attention to detail and understanding of the system during the design of the swing rack. This is why it is critical
Tim A. Schultz, Caterpillar Inc., USA, outlines how precision design, operating techniques, and proper maintenance are all key to getting the most life out of a swing rack.
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for a swing rack supplier to understand the loading and subsequent fatigue the swing rack will endure. The swing rack design for Cat electric rope shovels has evolved over time. Today, the entire rack is cast in steel prior to welding a hardened steel piece ring, in order to provide a stable base for the revolving frame and flow of stresses through the machine. This change to minimal welding and the steel casting, along with other updates, has led to the lowering of swing rack system maintenance by up to 40%.
Figure 1. Swing racks support the entire weight of the upper works as well as absorb the reaction forces when digging material.
Figure 2. The swing rack is a precisely engineered system. Caterpillar analyses the molecular structure of the liquid hot metal to ensure quality.
Figure 3. The swing rack resides between the upper works and the undercarriage of the electric rope shovel, facilitating 360˚ rotation of the machine during operation.
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The swing rack roller assembly and centre pintle are the only components connecting the upper works to the lower deck of a machine, weighing more than 952 000 kg (2.1 million lb). Therefore, gear alignment for the large swing rack is extremely precise, as the gearsets require tight mesh control of 0.254 mm (0.01 in.) radially and 0.025 mm (0.001 in.) angularly. It is hard to imagine such precision is achievable in such a large working machine; however, attention to detail and fine tolerancing on each component related to the swing system allows the system to perform correctly for many years. Similar to a fine bearing, the swing rack also serves as the structure support for the removable and segmented bearing race, or rails. The geometry and metallurgy of the rails and rollers are extremely important as the full weight of the upper works bears directly on these components, while they facilitate machine rotation. Understanding how the machine is loaded during operation is essential to developing the proper roller and race designs. If these are poorly designed, pitting and progressive wear will develop quickly, resulting in costly repairs, machine downtime, and lost productivity.
Proper operation: the key to longevity As the swing rack system is difficult and expensive to replace, electric rope shovel manufacturers target a design life of 50 000 hours, or 10 years. Replacing a swing rack unexpectedly can cost a mine site millions of dollars in repairs and lost production, as the entire machine must be taken out of service and undecked, which can take weeks to complete. For this reason, proper operator training and machine operation are critical for the mine to maximise the service life of the swing rack. Electric rope shovels are built to withstand the demands of moving thousands of tonnes of material every day, over many years, but they are not indestructible. Improper operating techniques can place excessive stress on the rack, which can damage the component. One such ill-advised technique is swinging in the bank. When the operator swings the upper works at full speed, the machine responds by putting as much torque on the motors required to rotate at full speed. If the dipper remains in the bank while the machine begins its swing, the motors are giving full effort and begin to stall. Stalling the motor squeezes out every bit of lubricant from between the gear teeth before the metals contact. These teeth weld to one another under extreme pressure and are subsequently ripped apart upon the dipper breaking free from the bank. Thus, swinging in the bank tears the metal out of the gearing. This is the reason shovel manufacturers recommend a specific open gear lubricant (OGL) type to prevent metal-to-metal contact under stalling loads. Another common improper operating occurrence, which overstresses the swing rack and increases wear on the rollers and bearing rails, is stalling a dipper. Stalls occur when the operator crowds too far into the material, and the machine can no longer hoist the dipper, even under full hoist power. This results in overloading the dipper and using
the hoist motor to plough through material that is incapable of being removed by the machine. The load experienced by a swing rack may increase by up to 15% when the dipper is stalled. This may not seem like much, but it is significant, considering the fatigue life of steel and the fact that one of the rollers under the upper works may already be supporting over 226 000 kg (500 000 lb) during a normal digging load. To keep the electric rope shovel in the bank and minimise improper techniques like these, manufacturers have introduced machine operating software upgrades to assist operators. Caterpillar developed its Operator Assist – Enhanced Motion Control system for the Cat 7495 Series shovels. The software both simplifies machine operation and protects it from inadvertent misuse. Through reducing the occurrence of stalling the dipper and swinging in the bank – as well as boom jack prevention, crowd impact prevention, and crowd over-speed prevention – it can also help enhance production.
Experience matters With machines working in virtually every climate and with a wide spectrum of materials being mined, electric rope shovel manufacturers encounter local conditions that pose challenges to component longevity, but also an opportunity to improve component design. As an original equipment manufacturer (OEM), Caterpillar is held to high standards to
meet longevity expectations from its customers. According to the company’s engineers, whenever a unique issue is encountered, it is standard procedure to consider the entire system and how it operates as a unit to apply a fix. One such issue encountered by Caterpillar required specific swing rack design updates to improve component reliability and durability. The issue originated from a mine with operations in the Atacama Desert in Chile. Known as the driest non-polar place in the world, the desert’s average annual rainfall is approximately 15 mm (0.6 in.), with some locations receiving less than 3 mm (0.12 in.) per year. Mining operations in this region produce exceptionally fine dust during loading and unloading cycles. Many of these dust particles measure under 10 microns, and it is not uncommon for a shovel and loading area to be engulfed with this dust. Since these particles are prone to float or blow around when disturbed, the dust accumulates around machine components that are not filtered, sealed, or pressurised. In this particular scenario, among other components, dust accumulated in the swing rack and the fine particles increased abrasive wear to the gearing. Caterpillar and Cat dealer service technicians worked with the mine in question to analyse the issues found in the swing output pinions and swing rack assembly. One possible fix that was identified could have been to simply increase the pinion and/or rack harness.
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TOMRA XRT technology delivers a hand sortable product after only two stages: Concentration and Final Recovery. This simpliﬁes the process removing up to 7 diamond concentration stages resulting in signiﬁcant ﬁnancial and environmental beneﬁts: drastic reductions in capital investment and operational costs, as well as signiﬁcantly lower power and water consumption.
However, this would have only resulted in a minor improvement, and the company was looking to add strength without adding unnecessary bulk. Instead, the design team took a different approach. The fix focused on
the output pinion on each gearcase. The quantity of the output pinions was doubled to develop a single input, dual output gearcase design. The system could still be powered by the same 377 kW (505 hp) electric motor, but this design significantly reduced the loading on each pinion to deliver an improved rack-and-pinion life of nearly 400%. Along with experience, another advantage of this upgrade being made at the OEM level vs a component supplier is reach. Since Caterpillar developed this swing rack design standard on its own electric rope shovels, the success achieved with the new design in Chile could now be used to benefit the global mining community.
Back to basics
Figure 4. Fine angular and radial tolerances on each component related to the swing system allow it to perform correctly for many years.
Figure 5. Machine operating software updates help minimise improper techniques to protect the swing rack and keep electric rope shovels in the bank.
How an electric rope shovel is operated and maintained tells the final story of swing rack longevity. Implementing the basics of proper maintenance, adhering to service schedules, using specified lubricants and replacing components with OEM parts designed to work as part of the entire machine’s system, significantly contribute to increasing the time a machine spends in the bank. One simple way to maintain the swing rack is through machine operating technique in the pit. Electric rope shovels rotate, on average, within a 120˚ arc for loading and unloading, so the same pinion teeth interact with the same gear teeth repeatedly. Frequent machine rotation is recommended by Caterpillar, since rotating the machine after each shift allows the lubricant to be dispersed to the entire swing rack and pairs new pinion/gear tooth combinations, resulting in more gradual and even wear. Harsh operating conditions – sub-zero temperatures, extreme heat, unintended misuse, and significant quantities of dirt/fine particles – play a significant role in the service life of a swing gear. This makes using lubrication, and specifically the right type of lubrication, critical. Using a recommended open gear lube, such as Caterpillar OGL, which is specifically designed to prevent metal-to-metal contact under stalling loads, provides a film that adheres to the gear teeth in extreme conditions. OGL also includes high pressure additives formulated specifically for extreme loads and stalling conditions to protect against gear scuffing and wear. With the demanding operating conditions swing racks face, it is normal for material to flow from the edges as the machine bears the full inertia of the system on the gear. Proper maintenance practices include trimming this metal flow from the tips and ends of the teeth. Any shavings must be removed from the teeth prior to putting the machine back into service.
Figure 6. Undecking the machine to replace the swing rack is extremely expensive. Proper design and good operating practices are essential in ensuring the component lasts to its design life.
18 April 2021 // global mining review
Operators will often interpret the robust nature of the machine to mean that the swing rack gearing is capable of taking on ‘anything and everything’, however this is not the case. Swing gear systems are highly precise and are sensitive to poor maintenance practices. Inspections, lubrication, and responsible operating techniques make a significant difference in extending the life of the swing rack. Gear that is cared for will be there to work, both today and tomorrow.
Boosting payload compliance to increase productivity
Figure 1. The fill bar shows the operator the payload of each fill in real time, together with the total amount loaded. Each truck’s name and capacity are clearly shown below the fill bar.
Figure 2. While truck loading is in progress, Argus’ truck fill bar alerts the operator to any minor (orange) or major (red) overloads while a truck load is in progress. This reduces truck overloads and underloads, in addition to improving cycle and load time, payload accuracy, and overall shovel output.
20 April 2021 // global mining review
Material handling is one of the most important processes in mining. If mines are to remain sustainable in a depressed market, adopting technologies, such as payload monitoring systems, is a good way to contain costs and improve efficiency. Shovel-based payload monitoring systems provide operators and mine site personnel with real-time payload information that enables haulage trucks to be filled to their correct payload targets consistently. By providing real-time, bucket-by-bucket payload feedback to the operator, productivity and production tonnages can be increased to achieve tighter payload distributions. Accurate truck payload management and improved operator performance can also result in significant maintenance savings due to a reduction in machine stress on both the shovels and trucks. An easy way to eat into the profitability of a mine is to overload a haul truck. Not only does it jeopardise the safety of the haul truck driver, but also the mining asset. There are many common problems that are associated with overloading. For example, when a truck is overloaded with material it puts the structure and frames of the haulage unit under severe stress, causing increased fuel consumption, engine overheating issues, and reduced tyre and component life. All of these contribute to increased unplanned maintenance costs. Overloading also increases the chance of spillage, which can damage haul roads making them unsafe to drive on, and reduces the efficiency of a mobile fleet. At the other end of the scale, underloading a truck can cause just as many production issues, as the driver is required to complete more trips for the same amount of material, burning more fuel and wearing down tyre life. When shovel operators load trucks without any payload information, it is almost as if they are operating blindly. There is so much room for productivity inefficiencies if this element in the load and haul cycle is not managed correctly. The use of traditional truck-based methods is still adopted in mines throughout the industry, however there are challenges and inaccuracies that can come with this. For instance, truck-based payload methods do provide payload information, however these methods often provide delayed or inaccurate data to the haul truck driver, sometimes with quite significant repercussions. Any delay in payload information being delivered to the driver can sometimes mean that they have already driven off before being alerted to the fact they are overloaded. This slows down production, as once the truck is alerted to the overloading it is required to dump-off and return to the shovel for re-loading. Another benefit to some shovel-based payload monitoring systems is an open application programming interface (API) architecture. The open API architecture and original equipment manufacturer (OEM) agnostic nature of most shovel-based systems offers mines the option of integrating with other third-party systems and the flexibility to standardise across an entire fleet. As mines look to become more connected and share data up and down the value chain, open API architecture is becoming a must to truly optimise a mine’s productivity.
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Shovel-based payload technology in action MineWare recently worked with a large US coal mine that practised this manual approach and discovered that they were operating at under 40% payload compliance. The operators were found to be reliant on manual processes and truck weights only, which can be unreliable and inaccurate, resulting in poor payload management, an increased number of truck overloads and underloads, and significant variations in operator performance. Through the adoption of Argus, a shovel-based payload management system, the site saw a significant improvement in overall payload performance, resulting in a 35% increase in haul truck payload compliance. Shovel-based payload systems, like Argus, take out the guesswork for the operator and provide them with the information and training they need to improve and benchmark performance. Argus, in particular, supports continual improvement and benchmarking for supervisors and management with key performance indicators (KPIs), scorecards, and reporting.
The future: smart, interoperable mining Throughout the mining value chain, most mines worldwide operate mixed fleets of equipment, utilising multiple technology solutions that monitor and provide data for different areas of their operations. As mines continue to advance on the path of automation, it is of critical importance that technologies, such as shovel-based payload systems, are open and interoperable. Data collected from individual mining technologies need to be shared up, down, and across the upstream and downstream processes for a mine to take the next step towards automation. Once silos start to be broken down, data is shared and integration occurs. That is when mines start to see the greatest enhancements in productivity, not just in the load and haul cycle, but across their entire value chain.
For example, there are greater benefits to be had by integrating shovel-based payload management systems with fleet management systems. The integration of a mine’s shovel-based payload system and fleet management system means that neither the shovel nor truck operators need to rely on truck weights to measure payload accurately. By displaying real-time payload information from a shovel-based payload system on a fleet management system screen, both shovel and truck operators can ensure the truck’s optimum payload target is achieved each and every time. This type of integration alone means that miners can reduce the number of truck underloads and overloads, ultimately reducing their cost per tonne. Once other technologies begin to be incorporated and integrated, such as machine guidance technologies, it becomes more than just ‘getting the right amount of material’, but more about ‘getting the correct type of material to the right truck in the right place’. Integrating precise material information with payload information in a fleet management system provides equipment operators and processing personnel with more accurate information and feedback on the type of material being loaded and hauled. The effects this has on the downstream processes can be substantial. Indeed, better classification at the pit leads to better production during the crushing and conveying process. By feeding material type and concentration data in conjunction with payload information from the shovel to the fleet management system, the driver knows exactly where to go – whether that be to the run-of-mine (ROM), a stockpile, or waste point. Without this information, mines have the potential to lose millions of dollars a year, due to dilution or contamination of ore and poor stockpile management. As the demand for integrated solutions continues, Komatsu technology companies, MineWare and Modular Mining, are developing and deploying these types of integrations for their customers. For example, by leveraging Modular Mining’s recently-launched Payload System API, mines are better able to improve their payload accuracy to reduce the bell curve, getting as close as possible to the target payload consistently. By consolidating truck and shovel payload data – such as that from the Argus Payload Monitoring System, in addition to third-party applications – as well as inputs into the DISPATCH and ProVision systems, the API presents vital information in a single, unified interface. The Payload System API also centralises reporting, while helping to decrease instances of truck over or underloading.
Figure 3. Argus’ colour-coded, in-cab software display provides actionable information to the operator. The dynamic truck fill bar to the far right of the display helps the operator hit precise loading targets first time, every time.
22 April 2021 // global mining review
As digitalisation and automation continue to transform mining, it is essential to provide mines with the ability to connect the dots and close the feedback loop between load and haul and other mining processes. With metal prices projected to improve in 2021 and CAPEX funding becoming available, this is a great opportunity for original technology manufacturers to deliver interoperable mining technology that ultimately delivers better connected, safer, and more sustainable mines.
Diogo Craveiro, Vermeer Corporation, USA, provides an overview of the benefits of continuous surface mining methods.
ining plays a vital role in everyone’s daily lives. The material extracted by surface mining operations creates energy and is used by manufacturers to develop machinery, technology, and the infrastructure people use every day. Through continuous surface mining methods, today’s miners are actively taking steps to make mines safer, more sustainable, and better neighbours to nearby communities. Continuous surface mining is proving to be efficient and more sustainable for many mines. Using surface excavation machines equipped with powerful cutting wheels to break up hard, rocky material often requires fewer steps than drill and blast methods. Continuous mining methods can also significantly reduce the material handling time at many mines. Material can be extracted a layer at a time, and the process produces consistently sized material that typically does not need to be run through a crusher. Today, surface excavation machines (SEMs) are working at mines ranging from precious minerals and stones to quarry operations. For many of the mines using continuous surface mining methods, equipment, such as the Vermeer Terrain Leveler® SEM, has made it possible to extract material in
areas deemed ‘off-limits’ to traditional drill and blast mining – due to increased regulations and community pressures to reduce noise, vibration, and dust.
Diamond mining in Namibia, Africa Oranjemund, Namibia, is a diamond mining town on the northern bank of the Orange River. Having crossed most of southern Africa on its journey to the sea, the Orange River is rich in minerals where it meets the ocean. At the river’s mouth, the current slows and the rocky fragments settle out. The tide then drives the sediment up against the coast, forming banks of sand and gravel, and in amongst these deposits there are diamonds. However, retrieving the gems is far from straightforward for Namdeb, the public-private partnership that operates the mine. Because a lot of the sediments are ordinarily underwater, extraction involves creating seawalls beyond the natural coastline and draining the sandbanks behind them. Millions of tonnes of gravel then need to be extracted and taken inland for processing. Although it sounds simple, gravel extraction is a challenging process. The beach-like surface sediment hides a sculpted maze of bedrock with hollows and gullies several metres deep, and
global mining review // April 2021
those hollows and gullies are filled with the diamond-bearing deposits Namdeb wants to retrieve. For years, the procedure involved removing the surface gravels down to the first bedrock outcrops. Teams of workers were then deployed to empty the gullies using vacuum extractors – slow, labour-intensive work. Looking for a mechanised solution, Namdeb invited tenders, having identified the following four objectives:
To improve surveillance: A person who spots a diamond while they are out of sight down a gulley is going to be tempted. Taking the whole surface off: Being able to use the oversized material – the big lumps of solid rock – for seawall construction. Mechanisation as a way of increasing the clearance rate.
To improve the safety of the workforce: With the old mining method, there was too much risk of people slipping and falling, breaking arms and legs.
The viability of an operation like this depends on efficiency. When extracting and processing tonnes of sediment for very few carats of diamond, the work has to be efficient to make it worthwile. In response, Vermeer proposed the use of a T1255III Terrain Leveler SEM. A new approach was envisaged, where bulldozers would first strip each newly drained block of ground. The Vermeer machine would then be brought onto the flattened site. It would proceed to cut layer after layer from the surface until the bedrock-to-gravel ratio made continuation uneconomical. In terms of appearance, the T1255III with single-sided direct drive is not dissimilar to a common rotating milling machine. However, its unique crawler-tracked design, combined with the direct-drive technology, made the T1255III the best fit for the job. Most machines used in surface mining have a lot of high-wear mechanical drive components – things such as gearboxes, chains, and sprockets. Being a direct drive, the T1255III does not have anything like that, making it reliable and more than capable of making its way through the mix of bedrock and gravelly sediment on the Namibian coastal site. A year on from its initial deployment, the machine is in continuous use. Diamond mining is expected to continue at Oranjemund for some years to come. Then, once the viable deposits have been extracted, Namdeb will breach the seawall and return the site to the ocean. In another generation, the area will simply be another part of Namibia’s precious wilderness, with no sign of the sophisticated mining operations enabled by Vermeer’s SEM solution.
Figure 1. At the Namdeb diamond mine, a Vermeer Terrain Leveler SEM cuts layer after layer from the surface.
Figure 2. The unique crawler-tracked design combined with the direct-drive technology of T1255III allows miners to chew through the mix of bedrock and gravelly sediment on the Namibian coastal site.
Figure 3. Around 95% of the material cut with the Terrain Leveler SEM produced particle sizes below 25.4 cm (10 in.) at a mine in Iquique, Chile.
24 April 2021 // global mining review
Iodine/nitrates mining in Chile, South America A prominent mine in Iquique, Chile, also started using continuous surface mining methods in 2017. The mine had a goal of taking a broader approach and evaluating the benefits of continuous surface mining from pit to heap leach. Results have been measured and compared with traditional drill and blast methods, and after almost 3.3 million t of material cut, the benefits are clear. The mining operation has reported positive results in the areas of material separation, more consistent particle sizes, and gains in the heap leaching process. Continuous surface mining helped resolve dilution issues because of the way the Terrain Leveler SEM cuts material in layers. With a modulable cutting depth, miners can be highly selective in the way they recover the mining ore with minimum presence – if any – of sterile material. Geological mapping of a pit can also result in less dilution. It can help improve efficiencies through the whole process, from the loading and hauling of rich and concentrated mineral ore to a heap leaching process with a high level of mineral recovery. The effectiveness of the leaching process can be affected by the direct particle size output of the blasting stage.
PROVEN IPSC SOLUTIONS MMD remains at the forefront of In-Pit Sizing and Conveying (IPSC) technology, developing bespoke mobile and semi mobile sizing solutions large and small for many types of applications around the world. Our latest relocatable IPSC stations have successfully been combined with ore diverting solutions and new ore sensor technologies, to enable separation of ore from waste in the pit whilst uplifting ore grades through ﬁnes recovery. Introducing an automated ore sorting solution into your existing system ensures only the pay material is hauled to the process plant – meaning your mine can improve production whilst reducing energy usage, water consumption and tailings requirements. Whether you have an underground or open pit operation, our network of technical experts can help develop a tailor-made in-pit sizing and sorting solution to boost productivity and deliver a leaner, greener mine.
Typical Bulk Ore Sorting Solution
Under normal conditions, blasting is simply not able to control or guarantee a consistent particle size. Inconsistent particle sizing can result in poor recovery during heap leaching stages. With continuous surface mining, there is a high level of consistency in particle sizes, resulting in better mineral recovery in later heap leaching stages. On top of that, avoiding big chunks of rocks – very common in blasting – increases the hauling process’s efficiency as more material is transported in a given spatial volume. Around 95% of the material cut with the Terrain Leveler SEM produced particle sizes below 25.4 cm (10 in.) at the Iquique mine. The results of mineral recovery created by continuous surface mining with the Terrain Leveler SEM showed 12% more mineral recovery than heaps with traditional mining. This mineral recovery rate was also achieved in a period 33% shorter than using traditional mining methods.
Quarry mining in Switzerland, Europe For more than 125 years, Switzerland’s Jura Cement, a subsidiary of CRH plc, has served as a manufacturer and supplier of building materials. However, mounting community pressure regarding dust emissions, vibrations, and noise threaten the company’s future at its largest quarry operations. To address these concerns, Jura Cement is implementing new precision surface mining methods to help secure the quarries’ future.
Figure 4. The team at Jura Cement brought in a Vermeer T1255III single-sided direct drive with an optional dust suppression system to help address concerns about dust emissions.
Comprised of two production plants, Jura Cement produces more than 1.1 million t of cement. The bulk of its annual production is mined at its quarry operations in Wildegg, which first opened in 1891. There was nothing but open land around the quarry in those early days, but, as the mine and surrounding community have expanded, the bordering area between the two has continued to shrink. There are now residential areas surrounding three sides of Jura Cement’s Wildegg facility, and this has contributed to growing concern from local inhabitants about how the mining operation extracts limestone for the quarry. In order to address these concerns, several years ago, quarry officials conducted an internal investigation to determine how they could be better neighbours to the community, while producing the materials required by their customers. Based on Jura Cement’s findings, it was determined that it needed to lower blasting-induced ground vibrations, which were already relatively low, to ease the concerns raised by the surrounding community. The search for alternative mining methods started in 2012, and since then it has explored several mining techniques, including: rock excavation using a hydraulic excavator; ripping material with dozers; and specialised surface excavation machinery. Based on its findings, using SEMs is the most efficient mining method among those the company tested. The team at Jura Cement brought in a Vermeer T1255III single-sided direct drive with an optional dust suppression system to help address concerns about dust emissions. The unit also incorporated Vermeer SmartTEC performance software to aid with control adjustments and recording machine productivity, Vermeer Telematics to monitor and track fuel consumption and hours, and a full-function remote control. During an initial trial period, the Jura Cement team paid close attention to production rates, machine operational costs, service support, and operator feedback. The Terrain Leveler SEM achieved an average production cutting efficiency of 275.6 tph while working in soft-to-medium rock, up to 80 megapascals (11 603 psi), at Jura Cement jobsites. With a fuel consumption average of 70.9 l/hr (18.2 gal./hr) and normal preventive maintenance expenses, Jura Cement’s operational costs fall in line with other drilling and blasting methods when working in soft and heavily ragged rock. The Terrain Leveler SEM also allowed work close to the edge of the cut, and a lower centre of gravity provided stability on uneven terrain. The assisting tools built into the Terrain Leveler SEM and at the conclusion of its trial rental period, Jura Cement evaluated all of the results and chose to extend the rental agreement for the Terrain Leveler SEM. The strides made with continuous surface mining methods have helped Jura Cement earn community officials’ and residents’ trust and respect. They can see that Jura Cement is taking their concerns seriously and are taking the necessary steps to verify that the quarry can remain open and continue to expand in the future.
The future of surface mining Figure 5. The Terrain Leveler SEM also allowed work close to the edge of the cut, and a lower centre of gravity provided stability on uneven terrain for Jura Cement.
26 April 2021 // global mining review
Developing more sustainable mining practices and mitigating the safety risks associated with drilling and blasting has surface mining operations worldwide turning to continuous surface mining methods.
Alek Duerksen, Emerson, USA, explains the difficulties of tailing disposal and provides suggestions for choosing the proper automated isolation valves for this service.
ailing disposal can be one of the more difficult aspects of mining operations, creating significant challenges for the automated valves used in tailing distribution systems. Tailings are the leftover materials and waste generated after the economically extractable ore has been removed in a mining operation. They primarily consist of dewatered pulverised rock, dirt, and gravel. Tailing material is generally thick, viscous, dense, and very abrasive – and in some applications the tailings may be considered hazardous. The material can be very unforgiving when it flows through an automated isolation valve (Figure 1). Mining extraction operations are often located far from the tailings containment ponds, so the material must be piped over very long distances, sometimes kilometres. The long pipe runs and very viscous nature of the tailings often
necessitate the use of high-pressure pumps to move the material through the pipelines. Once the material reaches the containment pond, it must be distributed evenly across the surface. In order to facilitate this process, the tailing piping system has a number of smaller pipes called spigots, which branch off the main line and divert the tailings to various locations around the containment area (Figure 2). Each spigot has an isolation valve, usually automated, that can be opened or closed as necessary to ensure the containment area fills uniformly.
The trials of tailing valves Most tailing distribution systems utilise knife gate valves designed for handling abrasive slurries, but tailings systems pose many unique challenges. The viscosity, low water content, and abrasiveness of the tailings tends to
global mining review // April 2021
wear the valve body quickly, while degrading and ultimately destroying the elastomer seats necessary for valve sealing and shutoff. Line pressure can be very high in the distribution network, yet relatively low at the spigots due to pressure drop in the very long pipelines. This means that different
valve designs may be necessary in different locations. Hazardous tailings, such as those often found in oil sand applications, may require zero-leakage, ASME-rated valves to eliminate leakage outside the designated containment dike. All of these issues combine to make proper knife gate valve selection difficult. Fortunately, there are a number of knife gate designs offering a range of capabilities to suit the needs of most tailing distribution system applications.
Figure 1. Tailing material is viscous and abrasive, creating a very difficult application for automated valves.
In many mines, the spigot valve is a low-pressure application that is located inside the containment dike. In this case, a standard low-pressure knife gate valve (Figure 3) may suffice, provided that it includes a number of key design features. The valve should be full bore to reduce wear, and it should incorporate strengthened, long-life elastomers to create tight line shutoff and extend service life. Wearable valve components should be easily inspected and replaced, ideally in the field. The valve should also offer some type of hydraulic actuator because many operators use a portable hydraulic unit to actuate valves. In most cases, the valves are so far apart and remote that most mines have a portable hydraulic unit in a truck that is driven to the valve and temporarily connected to it for actuation. Discharge to the environment is acceptable in a valve in this application, but it should be minimised.
Figure 2. Spigot pipes tee off the main tailing distribution line to feed various sections of the containment area.
Figure 3. Each spigot has an isolation valve to control tailing flow to a particular zone so the material is uniformly spread across the containment surface.
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In hazardous tailing applications, or as the valves move upstream in the tailings distribution network and experience higher pressures, the process conditions become more challenging. Many of the same requirements discussed for spigot valves still apply, but there are now higher pressures and higher material velocity, requiring a different valve design. Hazardous tailing applications require zero atmospheric leakage, which can be difficult to achieve in a knife gate valve. These applications also see higher pressures, so true ASME Class 150 or 300 ratings are usually required. In addition, valves in tailing applications are subjected to higher material velocities, so valve wear becomes a significant problem. Valves for this service must be full bore, and often employ replaceable wear rings on the valve body to absorb the brunt of the abrasive forces and extend valve life. These rings should be installed on both the inlet and outlet side of the valve, and they should allow rotation to different wear positions, in order to extend service life. The valves are also fully bi-directional and provide the zero-leakage shutoff required in many of these applications. Of course, easy valve maintenance and replaceable parts are critical for this kind of service as well.
Most difficult service Valves located near the beginning of the tailing distribution network face the most demanding
process conditions. They are often subjected to very high pressures and abrasion rates, yet still must provide zero leakage line shutoff while maintaining the zero atmospheric leakage required for hazardous tailing applications. Selecting the right valve for this service is therefore critical, but can also be very difficult. Higher pressure applications require ASME Class 300 service, which is relatively uncommon in a knife gate valve. The valve port must be round and full bore so tailing material turbulence and abrasion are minimised. In addition, valves in this service should employ replaceable and rotatable wear rings to maximise service life under punishing conditions. The toughest applications should utilise valves with the capability to match internal pipe diameter with zero pocket between the seat and wear rings for the very lowest pressure drop, reducing downstream turbulence. Seal design is critical for high-pressure applications, so the design of the valve shutoff and atmospheric seals require a number of special refinements that are quite different from lower pressure valves. Users should examine the seal designs and components carefully when selecting the valve, because these components will see the highest wear and are often the first to fail. Proper selection of soft seat materials, as well as easily replaceable internal components, are critical for long service life and lowest total cost of ownership.
Proper selection saves time and money Some users fail to consider the requirements for a specific application and install whatever gate valve they happen to have in stock. This either results in a valve that is far more expensive than required, or, more commonly, a valve that is poorly suited for the task. In that situation, premature seal failures, poor shutoff, and high maintenance costs typically result. When the failing knife gate valve is replaced with a correctly designed model, the improved performance and greatly reduced maintenance often pay for the upgraded valve quickly. If a valve requires frequent repairs, it is likely a good candidate for a re-evaluation and possible replacement.
Conclusion Tailing distribution applications pose a wide range of challenges for knife gate valves, and rarely will one valve design handle every service. A number of very different knife gate valve designs must typically be employed across the network to satisfy process requirements. Careful selection of valve capabilities and design features allows the user to balance long and reliable service life with upfront investment to achieve the lowest lifecycle cost. The long-term operational savings of a well-designed body style, critical sealing systems, and replaceable components will offset and often dwarf the slightly higher initial investment required for the proper valve.
CHANGE YOUR MINE. THE RISE OF CONTINUOUS SURFACE MINING It’s called: continuous surface mining. Using a machine like the Vermeer Terrain Leveler® surface excavation machine (SEM) to perform continuous mining allows you to methodically mine or prep a site layer by layer — optimizing productivity and precision while eliminating many of the safety challenges and restrictions associated with drilling and blasting.
Visit vermeer.com/changeyourmine to learn more. Ver Verm ermeerr Corp C orat Cor a ion on re r erves the rese h right to make changes in engineering, design and speciﬁcations; add improvements; or discontinue m fact manu fac urin u g at any ann time without nootice tic or obligation. Equipment shown is for illustrative purposes only and may displaay opption ti al tio accessories e or compo omp nents nent entt speciﬁ eciﬁ ciﬁc to the heeir globa global region. Please contact your local Vermeer dealer for more informat a ion on machine ne specciﬁca ﬁcation ﬁca tioons.. Verme erm er, er the th Verm erm ermeer rm logo andd Command man er are trademarks of Vermeer Manufacturing Company in the UU.S. and/oor oother mand countrie coun trtr s. © 202 0021 Vermee Verme me r CCorporatio at n. Allll Ri at Rights Reserv rvved. ed
Gaurab Nakarmi, TSURUMI PUMP, Japan, addresses the importance of pump efficiency to the mining industry.
Figure 1. Heap leach mining site with Tsurumi LH-series pumps.
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here is no doubt that mining is an extremely water-intensive industry, with some estimates putting water requirements at over 250 million l to mine and process 1 t of gold.1 As the higher-grade ores for various metals and minerals deplete around the world, the demand for water in ore processing increases; that is to say more water is required to extract the same amount of product. In a survey among 54 of the world’s largest mining companies with a total market capitalisation over US$1 trillion, Carbon Disclosure Project found that 91% reported being exposed to water and related risks. In addition, 61% expected the risks to materialise within the next 3 years, resulting in immediate financial impacts.2 There is extreme pressure on mining companies to manage their water usage sustainably. The high demand for water usage also puts the mining industry in a crucial position to reduce mankind’s impact on the environment, and to become an integral component in achieving the Sustainable Development Goals signed by the 193 United Nations member states.3 Mining companies can
focus on better and more energy-efficient water management systems to form sustainable water usage practices, resulting in the reduction of water waste and energy consumption. This incorporates the understanding of the water resources, water usage, and water handling systems in mining – including pumps and control systems. In Tsurumi’s experience of developing pumping equipment and systems for the mining industry worldwide, the one constant is that an efficient and reliable system starts from the equipment designing team and needs to match the requirements at the mining site for sustainable operation with minimum downtime. A solution that has been well-thought-out on the drawing board of the designers' table, coupled with a proper operation and monitoring system at the mine, is the way to achieve optimised solution with controlled costs and higher efficiencies. The responsibility of creating a sustainable and robust pumping and water management solution begins at the research and development stage and continues into the
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operation and maintenance phase at the mine. Along this journey, the equipment needs to be supported by smart technologies and regular monitoring, with timely maintenance to keep them in desired operating conditions.
Developing an efficient pump During the design stage of a mining pump, various considerations are made and many factors are analysed. However, the primary focus is always on reaching the optimum efficiency of the pump. The pump body components are designed to fulfill the possible site conditions, while producing maximum performance output with minimal energy consumption. After that, the maintainability and life of the pump are prioritised. The cooling system of the motor is one of the elements that affect the overall life of the motor and eventually the pump. Therefore, pump designers continuously ponder on the flow path of the discharge so that maximum cooling can be obtained even in conditions with extreme fluctuations in water level and temperature. Top flow discharge in submersible
pumps is one of the results of such developments based on attaining higher cooling efficiency of motors. Similarly, the load and easy replacement of lubrication of bearings are also well thought out during the pump design phase. Some industry-leading pumps provide dual suction impellers to reduce the axial load on the bearings. The balance between the flowrates from two suction ports is adjusted to create minimal thrust loads. Additionally, grease replacement ports are also provided externally so that the pumps do not need to be disassembled in regular maintenance. Most mines have tough operating conditions, with abrasive materials or corrosive liquid highlighting the importance of resistance to wear and corrosion crucial. So, material selection of pump parts is also quite important to prevent unexpected equipment failure at the site. All of these might seem minor components of pump design, but each of them plays a vital role in successful equipment development, which leads to the reliable and efficient water management solution at mining sites.
Selecting the optimal equipment Depending on the type of mining activities, there could be numerous stages where water handling and management are required. There is no general-purpose one-size-fits-all solution in water management at mining sites. Water could be used in minerals processing, slurry transport, post-mining landscaping, dust suppression, or simply mine dewatering. Each application is critical on its own and without which the entire operation would come to a halt. However, each of these and many other pumping applications at a mine site have differing requirements. Hence, the most appropriate equipment is also different and special care is needed during the selection. The following are major considerations, which are common during pump selection for a mining water management application.
Required duty point
Figure 2. CFD analysis to reduce the losses inside the pump body and improve the motor cooling efficiency.
The required flow rate and total head or pressure for the application is the starting point for pump selection. Calculation of pressure losses in discharge piping becomes the crucial factor in determining the required total head. Foresight is particularly important in determining any fluctuating criteria, such as: seasonal excessive flow requirements, changes in the total head as the mine becomes deeper, or changes in the water level.
Water composition and pump material
Figure 3. Deep underground mines with silts require suitable pump materials.
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Any presence of solid particles should be analysed before selecting the suitability of a pump. Water with abrasive particles will require hardened materials to prevent wear and material erosion. Also, pumping of liquid with solids requires higher flow velocity. If highly acidic or alkaline chemicals are present in the water, the pumps will require corrosion-resistant materials for consistent and reliable performance. This is not only for metals, but special care should also be taken of elastomers and any other wetted materials. A pump with 316 stainless steel might work in highly acidic conditions of pH level 2, but NBR gaskets on the same pump might give away and lead to pump failure. Similarly, water temperature also needs to be taken into consideration. Oftentimes at mining
sites, there is underground water that needs to be dewatered which is hotter than regular surface water temperature. Suitable materials and pump specifications (motor insulation class, cables, seals, and gaskets, etc.) need to be selected for high-temperature operation.
Weather and altitude of the site Another crucial factor to consider is the weather and altitude of the site. Pumps at high altitude mines are susceptible to cavitation. Weather patterns with infrequent but heavy rainfall might require standby pumps. These site conditions should be studied during pump selection.
Size and condition of the installation The size of the installation site, along with any existing discharge piping, should be properly studied. The selected pump should be appropriate for the site, and the design of discharge piping should also consider any chances of water hammer and airlock. Necessary countermeasures should be taken, and thought should also be given to portability or permanent installation options for the pumps. Mining is often a transient activity, moving from site to site in a few months, or at most a few years. So, portability could be essential.
Power supply and limitation at the site The supply voltage, frequency, and limitations on the existing control panels should be studied before pump selection. The motor and cable specification should then be made according to the site condition.
Starting method and control system Depending on the desired starting method, the cable specifications of the pump differ. Sometimes the signal cables and other considerations are also required. Therefore, pump starting method and control systems with sensors should also be considered before pump installation.
On-site maintenance capability Regular maintenance of the pump directly relates to the overall pump life. Some mining sites might not be capable of performing full scale on-site maintenance. Pumps with longer life or sturdier materials might be necessary for such sites.
Operation and monitoring For efficient operation of a pump with minimal energy consumption, the performance of pumps should be maintained according to the site requirements. There are various solutions for this. The simplest one is to install a variable speed drive for the motors. Any sumps changing flow level can be measured using radar or float sensors, so that the control systems can operate with real-time data. With Internet of Things (IoT) systems and remote virtual control panels, human on-site intervention at remote mining sites is not required. The advancement of technology has allowed mining companies to incorporate central control systems to monitor the pumps around the mining site from one location. Pump operation data including operating voltage, current, temperature, and vibration can also be monitored through automated data loggers and analysed periodically.
This allows the operator to foresee any problems and avoid undesired breakdowns and downtime.
Periodic inspection and maintenance Other than automated monitoring and data logging, periodic maintenance and inspection is also required for healthy pump operation. Most of the periodic maintenance instructions are usually provided in the instructional manual. There are frequent occurrences of high wear or corrosion in pump components where, due to the lack of inspection or maintenance, the operator is completely unaware until the pump performance significantly deteriorates, causing long downtime for parts replacement. In order to avoid this scenario, regular maintenance should be scheduled beforehand. Similar to
Figure 4. Tsurumi team leading the on-site maintenance of LH12185D model.
employee health checkups, machinery should also be regularly checked for tolerances and clearances of mating parts, such as the impeller and suction plates. On-site availability of replacement parts and standby pumps is also vital for proper water management at a mining site.
Case study: South America In some cases, pumps need to be developed specifically to meet the on-site requirements. One such example that Tsurumi did this for is a gold mine located at 3500 m altitude in the mountains of South America. The request was for a pump that could handle fluctuating flow rate according to the site conditions at a total head of over 65 m. The system was to be used in the heap leaching process to transfer percolated leach solution to the processing plant. The pump designers in Tsurumi had been working on the LH12185D pump with an 185 kW/2-pole motor, an expansion of the LH-series. The Tsurumi LH12185D has a feature of double suction from the top and bottom side of the impeller, which provides a higher flow rate and also helps in maintaining the thrust load on the bearing. The pump was installed in early 2018 onto a floating pontoon and operated without any problems for more than 8000 hours. With variable frequency drive, the flow rate is adjusted according to each mining operation's requirements. Tsurumi technicians visited the South American site in early 2020 to provide vital feedback on maintenance tips and tricks for the pump. Due to the convenience provided by the grease inlet and outlet port for the bearings, motor dismantling was not required. Pump parts were checked and gaps between impeller and suction covers were checked. The pump was replaced in the sump again and has since been in operation. Approximately 60 km away from this site, the same mining company was undertaking a post-mining landscape management project at another exhausted gold mine. Due to the underground seepage of sulfuric acid, the pH level of the liquid at some of the sumps was around 1.5 – 2. Under such extreme acidic conditions, the operator required highly corrosion-resistant material. Therefore, they have been using LH6110-14 and LH8110-14 fully stainless steel, 110 kW pumps for the past 3 years without any signs of corrosion.
Conclusion As evident from the case studies, proper effective water management does not only involve good pump design or understanding the site condition. It is the effective combination of an efficient pump suitable for the site requirements. Along this journey of the pump, various accessories for sensors and control systems facilitate the eradication of unnecessary energy consumption, leading to a successful system with minimal downtime and effective water and energy management.
Figure 5. Fully 316 stainless steel LH8110-14 model at post-mining landscaping site with pH 1.5 – 2.5 liquid.
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PROSSER, I., WOLF, L., and LITTLEBOY, A., 'Chapter 10: Water in mining and industry', CSIRO, www.publish.csiro.au/ebook/chapter/9780643103283_ Chapter_10 'CDP Metals and Mining Report 2019', CDP, www.cdp.net/en/reports/ downloads/4613 ‘Historic new sustainable development agenda unanimously adopted by 193 UN members', United Nations, https://sustainabledevelopment. un.org/content/documents/8371Sustainable%20Development%20 Summit_final.pdf
Brendon Cullen, RCT, Australia, examines the key factors driving technology decision-making in the mining industry.
utomation is transforming the mining industry and will continue to do so at an increasing rate, as new technologies become available and further optimisations of the mining value chain are realised. Mining leaders of today are educating themselves on the numerous technologies available and how they can deliver greater safety, productivity, and efficiency to their operations. As the mining industry is embracing digitalisation and individual technologies are now well established, the focus has shifted to integrate interoperable technologies that facilitate better business enterprise platforms. RCT is an example of this, enabling the delivery of the latest technologies in vehicle control for any mobile equipment through its Drive-by-Wire (DbW) packages.
Interoperability It is one thing to have all the latest technologies in place, operating at a mine site, but the key to returning value on a mining company’s investments is to have them all work together – which is why interoperability is such an important feature in design. Interoperable systems and suppliers that are able and willing to work with other technology providers to deliver tailored customer-focused outcomes are becoming preferred choices for miners. This is due to the fact better business outcomes can be realised when compared to a closed (non-interoperable) system or single vendor strategy. Systems that are able to operate across various generations of equipment, as well as different equipment manufacture
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types, offer clients a considerable advantage: reducing capital expenses and achieving faster returns on investment. This fully integrated mining enterprise allows companies to maximise value through effective planning and efficient operations. Interoperable systems are also advantageous as they enable seamless data capture, analysis, and reporting of all systems. This includes mobile equipment, fixed assets, people, and the environment.
Case study: AngloGold Ashanti Australia’s Sunrise Dam, Australia An example of interoperability is the work RCT has done at the AngloGold Ashanti Australia’s Sunrise Dam gold mine in
Figure 1. RCT has implemented automation at mine sites around the world.
Figure 2. RCT's MMC feature allows one operation to select between and control multiple machines from the one automation centre.
Western Australia, Australia. The mine is contracted by one of the world’s largest hard rock underground service companies, Barminco, and operates both Sandvik and Cat loader fleets using RCT’s ControlMaster® automation. RCT platforms have allowed for the seamless integration of third-party technologies operating at the mine into the site’s current and future digital ecosystem. The site deployed RCT’s exclusive multi machine select (MMS) and multi machine control (MMC) features, which means that one operator can select between and control multiple machines from one automation centre. RCT also provided a public open application programming interface (API), which was integrated into the MinLog production management system. This provided information on machines in a specific area and identified the particular machine under control at that time. In addition to this, it sent production information off-site to be analysed in the cloud and transferred back to Barminco for their business intelligence (BI) system. The site’s existing automation centre located on the surface of Sunrise Dam mine site was easily updated to facilitate these changes. This was helped by the company’s ability to integrate with different brands of original equipment manufacturer (OEM) machines and third-party information systems.
Automation Each mining operation faces its varying challenges. What works at one mine site in particular conditions might not be ideal for another. The ability to scale automation technology to suit a company’s operation is an important key to delivering overall business efficiencies, for example: moving more tons, eliminating unplanned downtime, and increasing personnel safety. This scalability allows companies to implement automation in a staged approach, without complicating the project or taking on a high operational cost burden. An example of this is underground load haul dump (LHD) applications. By implementing technology that is scalable and agnostic, it allows companies to install to existing or new LHD machine fleets. Further optimisation of the production cycle was realised as day-to-day bottlenecks moved through the value chain, from entry-level solutions to advanced solutions: i.e. full automation and remote operations centres (ROCs). All these systems require RCT’s DbW packages and have helped clients realise a lower cost of ownership and faster returns on investment, proving this method of interoperability ensures business improvement when companies add technology to their operations. With the majority of mine sites around the world operating mixed brand fleets, it is important automation can be applied to them all and that they work together effortlessly and efficiently.
Case study: Polyus' Olimpiada gold mine, Russia Figure 3. An example of RCT's Automation Centre, where operators can control machines from the comfort of an ergonomic chair.
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An example of this integration is a project RCT carried out with Caterpillar dealer Vostochnaya Technia for Polyus’ flagship operation, the Olimpiada surface mine in the
Krasnoyarsk region, Eastern Siberia, Russia. Here, RCT’s bespoke department, RCT Custom, designed, manufactured, and installed the ControlMaster solution to control a fleet of five Caterpillar 777F trucks, a Komatsu 1 PC-3000-6 hydraulic shovel and D-275A-5 dozer, and an Atlas Copco DML drilling dig. Being able to operate this mixed brand fleet via automation allowed the site to operate more safely and efficiently. MMS was also incorporated, allowing one operator to swap between machines, which allowed them to simultaneously clean up landslip while continuing production in the same area. This custom project saw the reinvention of the design of RCT’s existing surface drill console, which was downsized for ease of use. Two automation centres were deployed on site, allowing operators to manage the machines from a safe and comfortable environment – away from areas prone to rock fall and severe weather conditions. All components were specifically designed to withstand the extreme temperatures experienced in Russia and additional external lighting was fitted to the machines to ensure maximum operator visibility during shifts in the evening and winter months.
with family. This has been shown to significantly improve overall mental health and well-being. As discussed, there is not one straightforward solution for every mine site, but automation in some form is certainly applicable everywhere. The key, however, to moving forward in the automation world is interoperability — the ability of a system to work with or use the parts or equipment of another system. As the mining industry embraces the use of digital information, it is important for digital solution providers to make sure their systems can play an integral part in their customer’s digital ecosystems, without compromising safety and system integrity.
Automating mobile machines The implementation of an open interoperable automation system allows one operator to simultaneously control mixed underground, surface production, and auxiliary fleets. The ControlMaster automation range can be installed onto any mobile machine – on the latest released, as well as some of the oldest still in operation, anywhere in the world. The scalability of the systems are suitable for any company. RCT understands that all mines are at different stages of mining resources, and that an operator may only want to start with automating a single machine before expanding to full automation across their entire operation further down the road, when feasible. No mine map is required with ControlMaster automation. The technology recognises the unique environment and makes on-board machine decisions to optimise operations – this sets it apart from other systems that solely rely on uploading mine maps before they can begin work. Other differential key features of RCT automation include: MMC – one operator can simultaneously control multiple machines on-site; MMS – one operator can control more than one machine type from the same station; and multi fleet control (MFC) – one operator can simultaneously control an entire fleet of different machines on-site.
Figure 4. RCT Custom redesigned its existing surface drill console, which was installed to control the Atlas Copco drilling rig on site.
Figure 5. A Cat 77F dump trucks at the Olimpiada surface mine.
Conclusion The reality is that interoperable automation is the way of the future, with companies embracing the technology because of the exponential safety and productivity improvements experienced after the implementation. It has also benefitted the fly-in-fly-out way of life for some operators. Having the ability to control machines from a central location away from a site means personnel are required to travel less, which allows them to spend more time
Figure 6. Olimpiada is a conventional shovel-and-truck opencast operation in the Krasnoyarsk region, Eastern Siberia, Russia.
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Dr James Counter, Nalco Water, Australia, outlines how important the ability to monitor and model water composition is for mitigating scale.
rocess water scale and corrosion are persistent problems across mineral processing operations. The nature of the scale varies by ore-type, but it shares a common industry thread – it can damage equipment and impact productivity. There are several mechanisms that can help mitigate scale. One of the more powerful is the ability to monitor and model water composition.
Scale Scale – a rigid, tightly adhering deposit – forms when mineral compounds precipitate from process waters that are saturated with ions. These minerals precipitate when scale, forming cations and anions, exceeds its solubility product. Scale can reduce flows, cause inefficient heat transfer for cooling or heating, and cause downtime to
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clean or replace damaged equipment. Two common forms of scale include calcium carbonate and calcium sulfate, but several other types also frequent mineral processing environments, including: iron compounds, magnesium compounds, silicate compounds, and barium sulfate. There are several factors that can affect scale formation in a mineral processing environment, including: water quality, evaporation, temperature, accelerated kinetics, and changes in water or ore composition. To mitigate scale, mineral processing plants can change the conditions of their process water, such as pH or water source, or minimise scale with an anti-scale reagent. These methods require continuous measurement to ensure that they effectively combat the scaling challenges and ensure that they do not cause any downstream effects in the process. Nalco Water, an Ecolab company, believes that the key to scale control is the right combination of chemistry, technology, and automation. The company deploys proprietary automation and control solutions to monitor and manage the underlying conditions that can cause scale, corrosion, and other challenges. The type of solution varies based on the nature of the scale and operating environment, but all solutions share a common thread – they focus on diagnosing and mitigating the root cause of the scale and optimising the operational environment to remove bottlenecks and maximise productivity.
Maintaining optimal water conditions With over 40 000 units worldwide, Nalco Water’s 3D TRASARTM solution combines smart technology, chemistry, and control equipment to help maintain optimal water conditions. 3D TRASAR detects system variability and operational challenges, determines the corrective actions required based on proprietary chemical control algorithms, and ultimately helps deliver results that drive performance and operational savings. There are a variety of 3D TRASAR solutions for different types of water systems, including technology for cooling water, boilers, membranes, and other offerings.
Figure 1. Dense scale build-up in a process water pipe.
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Nalco Water applied 3D TRASAR for membranes to help protect a reverse osmosis (RO) plant at a gold mine in Australia. Located near an environmentally sensitive lake, the operation used a carbon-in-pulp leach process that required significant RO water. In this process, gold was chemically extracted from the ore and then recovered through a high temperature stripping and electro-winning process to produce the final gold bullion. To prevent corrosion and scaling, the elution process required ultra-pure RO water. Scaling would hinder the high-temperature heat exchanger systems that are critical to producing the gold. To help the plant operate at its required production levels, and to minimise the amount of water needed from the surrounding community, Nalco Water specialists and engineers helped design a new, state-of-the-art RO plant with an advanced multimedia filtration (MMF) pre-treatment system. To maintain optimal conditions with minimum scaling, the company used 3D TRASAR for membranes to monitor the plant’s performance remotely and optimise the dosage of the water pre-treatment chemicals. 3D TRASAR helped ensure the quality of the RO water production, which ultimately allowed the plant to maximise its production. The overall solution resulted in a US$6.2 million increase in gold production and saved the plant US$150 000 in assets by reusing old equipment. Furthermore, the solution allowed the gold plant to use significantly less water from the local community, saving US$200 000 in potable water costs. The overall economic value of the solution was US$6.4 million annually.
Automation in water monitoring Another type of automation technology that Nalco Water applies to manage scale is its Remote Deposit Monitor (RDM). The RDM takes mine water monitoring to a new level by directly measuring the actual scale formations and surrounding conditions. The RDM leverages real-time deposition data, and measures conditions – such as temperature, conductivity, turbidity, and pH – in order to help diagnose the root cause of scaling events. With remote connectivity, the RDM enables plants to understand their scaling parameters before visually inspecting their system. This technology helped another Australian gold mine mitigate their scale challenges and avoid maintenance and energy costs. The plant needed to reduce the cost of its treatment programme by improving its ability to respond to process fluctuations. Prior to the introduction of the RDM, the anti-scale solution was dosed at multiple points within the process water system, and the programme was monitored with scale probes. Nalco Water examined the existing programme to look for improvement opportunities, conducting a thorough survey of the site’s mechanical, operational, and chemical processes. The company determined that while the existing anti-scalant programme was effective under normal conditions, several undetermined system upsets were causing an increased chemical dosage.
With the implementation of the RDM, Nalco Water was able to monitor scale formation in real time and respond quickly to system changes. By monitoring the data provided by the RDM, Nalco Water was able to determine the root cause of multiple scaling incidents that resulted from system upsets, including an uncontrolled lime incident that resulted in high lime levels in the process water system, an erroring electronic flow meter that resulted in misread anti-scalant dosage, and poor thickener control that resulted in high suspended solids in the process water system. Consequently, the RDM helped the plant avoid US$265 000 in maintenance and energy costs. In addition, the RDM helped optimise the existing anti-scale programme for the plant, saving US$216 000 in chemical consumption costs. The overall economic value of the solution was US$481 000.
Prevention While both technologies can monitor water and scaling conditions in real time, scale is best addressed when it is prevented entirely. Nalco Water uses a powerful, predictive technology to model future scaling potential based on water composition. Called the Mining Optimizer, the programme allows a Nalco Water engineer to examine the specific process conditions of a plant and predictively recommend an optimised product based on each unique operating environment. The software considers the impacts of blended water and examines an entire site’s process water system to determine the optimal dose points, programme, and consumption. Nalco Water engineers used the Mining Optimizer to address the scaling challenges of a Chilean mining company. For this specific mining operation, every ton of ore needed approximately 2.5 m3 of water. This required a complex system for water recovery – the plant recirculated approximately 300 000 m3/d. Changes to the plant’s water management had increased the suspended solid levels in the process water system, and, as a result, the site experienced an unprecedented increase in scale formation that blocked process pipes. Nalco Water conducted a complete plant audit of the process water system using a cross-functional team of experts. A water map was created with a chemical and physical analysis of each water stream. Once the data was collected, the team used the Mining Optimizer to quickly evaluate the effects of different water blends. The Mining Optimizer helped to determine that the mixing of water streams was the primary cause of increased scaling, and that optimising the dose points for the existing scale control programme would improve its effectiveness and reduce the overall required dosage. By implementing the changes recommended by the software, Nalco Water was able to reduce scale formation in the plant’s process water lines, and ultimately reduce programme costs. Moreover, the Mining Optimizer’s modelling abilities helped the plant minimise future scaling incidents by ensuring that the scale control programme considered all water streams feeding into the process water system.
Conclusion A strong scale control programme combines good data, accurate modelling, and an intelligent application approach to mitigate the underlying conditions for scale formation. Continuous monitoring is required to ensure that scale control programmes remain effective and address potential challenges in each individual process water system. By using advanced automation, control and modelling systems, mineral processing plants can take control of their scaling challenges and minimise scale’s impact on productivity.
AUTOMATION RETROFIT LEADERS ASI Mining is the leading non OEM automation retrofitter in the mining industry. Since our first automation retrofit in 2006 with CAT 777s, we’ve continued to mature and scale. Today, we’re deploying AHS on 3 continents and have expanded our scope to provide autonomous solutions in multiple areas of the mine. ASI’s core mission has remained the same- to help mine operators improve safety and get more out of their mobile equipment assets through automation. As an independent technology provider, we offer true OEM agnostic, retrofittable solutions, with more interoperability and scalability than any other AHS provider.
OEM Agnostic Retro-fit your existing equipment, no matter what make or model.
Interoperable Compatible with Legacy FMS and participating OEMs.
Scalable Designed as a platform to manage automation for the entire mine.
ASI has: Automated over 90 different vehicle models (and counting). Collaborated on mining automation projects with partners and customers since 2006. Worked with dozens of leading OEM partners. Want to learn more about the benefits and considerations of automation retrofitting? See ASI’s Retrofit Guide at
Kesavan Vijayanand, TAKRAF, India, outlines the possible design features and challenges that may need to be overcome when designing an overland conveyor.
elt conveyor systems cover a wide range of applications – from mining or extraction to in-plant or overland, where they convey material over long distances, passing through curves and rough relief areas. Overland conveying has found increasing popularity due to its potential to continuously and efficiently transport material, while offering other advantages such as high conveying capacities, safe and reliable materials handling, and environmental considerations. However, for 100% effective availability and to avoid challenges such as material blockages, carryback and spillage, focus needs to be placed on optimising material flow along the entire conveying system, based on a thorough understanding of the properties of the material being conveyed. This is particularly critical when conveyors are required to traverse complex routes, such as those with steep inclines and
declines, multiple and/or tight curves, and numerous crossings.
Case study: Utkal Alumina, India A contract from Utkal Alumina International Ltd (UAIL) called for an overland conveyor system to transport bauxite from the mines to a new 4.5 million tpy alumina plant. TAKRAF successfully completed the approximately 19 km overland conveyor system for UAIL’s green fields project in Tikri, Raigada, in the Orissa state of India. This also included the longest single-flight conveyor system to be installed to date within Indian territory. With a high quality bauxite as its input, and tightly integrated logistics between the mines and the refinery, Utkal Alumina’s operating cost per tonne of alumina is among the lowest in the world. The bauxite for
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Utkal Alumina is sourced entirely from the Baphlimali mines, some 16 km (aerial distance) from the plant site in the Doragurha village. Prior to being conveyed overland to the processing plant, the bauxite is crushed to a size of -150 mm, with the fixed crushing package having been provided in 2012/2013 by a sister company, the then Bateman India (acquired by Tenova in 2012).
Conveying ore from mine to plant The scope of the overland conveyor project covered design, basic and detailed engineering, procurement and fabrication, right through to erection – which included civil and structural work, commissioning, performance guarantee test runs, and handover of the 2850 tph conveyor system. An intermediate transfer point and unloading station, including silos and buildings, were also supplied with complete electrical and instrumentation systems. The system design brief called for the primary crushed bauxite ore of size -150 mm to be fed from the mine end junction house, through a chute to an overland conveyor of 14.5 km. This overland conveyor, ending at an intermediate
junction house, in turn feeds a 3.6 km overland conveyor. The latter, shorter conveyor ends at a plant end junction house, feeding a 500 t material surge hopper via a two-way chute. The overland system comprises 2000 and 4000 tensile strength steel cord conveyor belting, with a minimum belt safety factor at a steady state of >5.5, supported on a series of underslung-type idlers. These, in turn, are supported on a structural system made up of ground modules and gantries, with the overland conveyors routed partly along the ground and partly along an elevated portion. From the surge hopper, material is fed either directly to plant conveyors or to a stockpile through stockyard conveyors supplied by others.
Advanced design and engineering The execution of the project represented a group-wide effort, drawing on the global overland conveying expertise of TAKRAF Group, with the length of the required conveyor system and the challenging topography along the conveyor path calling for state-of-the-art design and engineering. Industry-leading software was used to maximise routing and equipment utilisation and specifications. The conveyor design was supported by horizontal curve analysis and dynamic analysis to optimise the long-distance conveyor power and belt tensions. Global procurement was followed in order to optimise costs and also to source the most advanced and reliable components. Initially, two technologies were considered, overland trough belt conveying and cable belt, with the client selecting the former due to its many advantages in such inhospitable and remote terrain. In addition, a major advantage of using trough belt conveying was that almost all the components and spares for trough belts are available in India, with a very small percentage of imported components.
Designing for a complex terrain
Figure 1. A very undulating terrain typified the path of the conveyor moving bauxite ore from the mine to the Utkal Alumina plant.
Figure 2. Blasting and excavating were required for creating a suitable route through the hilly region of the conveyor path.
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In its final configuration, the system’s two conveyors traverse a highly undulating and complex terrain. Dropping in total by 250 m over its course from material loading to discharge, the conveyor system passes through 11 nalas (branch rivers), the Ratachuan River, one forest stretch of nearly 470 m in length, a high voltage line crossing, 37 road crossings, a paddy field adjacent to the plant boundary with a stretch of approximately 2.5 km, eight hills, and several villages. The elevated structures were provided with cage ladders spaced at approximately 150 m, and pile foundations were provided for the river crossing and one of the downhill crossings. As a result of the topography, and due to the conveyor length, the conveyors were designed with head and tail drives and multiple, very tight compound horizontal and vertical curves. In total, the conveyor system features 10 right hand curves, four left hand curves, and horizontal curve radii of 2500 m across all locations but one – a critical zone on the shorter conveyor where the horizontal curve is 1800 m. This portion of the conveyor passes over a hill and through the plant boundary. The longer conveyor has a ground module and a graded portion. The ground module comprises 17 straight sections, one left hand curve and one
right hand curve section, while the graded portion consists of 12 straight sections, two left hand curves, and four right hand curves. The overland gallery on both conveyors together features 403 straight sections, 154 right hand curves and 61 left hand curves, with a maximum gallery length/support interval of 49.5 m and standard gantry length of 27 m. The idler spacing for the straight and inclined portions of the galleries on both conveyors is 4.5 m for the carry idlers and 9 m for the return idlers, except for one section on the longer conveyor where the carry idlers are spaced at 3.5 m and the return idlers at 7 m. On both conveyors, the carry idler spacing for the horizontal curved galleries is 2.25 m and the return idlers are spaced at 4.5 m. With an installed power of 6 x 850 kW and 2 x 850 kW, the conveyor system features six drives at the tail end and four at the head end on the longer conveyor, while the shorter conveyor has two drives at the head end only. There are two belt turn-overs on each conveyor, one at the tail end and one at the head end. Each conveyor features a fail-safe hydraulic disc brake at the tail end. A take-up winch with capstan brake arrangement has been provided at the head end of both conveyors. The intermediate transfer point between the two conveyors is located in hilly terrain and, since the four head end drives of the longer conveyor are also located there, the conveyor drive and take-up areas are mounted on a portal steel structure. These lightweight but high strength structures provide the design flexibility to accommodate the terrain. Advanced material flowability testing and modelling were used in the design of the transfer chutes at the intermediate transfer point and the plant end junction house to minimise risks, such as: environmental pollution and spillage, accelerated belt wear, and blockages. To facilitate maintenance, approach roads and a mine road were made available all along the conveyor length, with the cage ladders provided on the elevated structures enabling ease of access.
Conveyor erection focuses on zero harm Erection of the conveyor system was complicated by the requirement to accommodate and minimise disturbance of the population of the various villages through which the conveyor system passes, as well as the need to blast and excavate a suitable route through the hilly region of the conveyor path. Approach roads for erection of elevated
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structures on the hilly terrains also had to be provided. With major equipment, such as heavy cranes and excavators, being used for the erection of the elevated structures, particularly in the challenging hilly terrain, TAKRAF India placed particular focus on safety, strictly conforming both to TAKRAF’s global promise of zero harm and to the client’s safety protocols. Performance guarantee testing was carried out over nearly one week, with the system consistently achieving its present capacity of 1500 tph. As a result, the conveyor system was handed over to the client in December 2016 at a special event where celebratory Pooja rituals were carried out in the presence of top management of both companies.
Case study: Chile TAKRAF also delivered the world’s most powerful belt conveyor system for Chuquicamata in Chile, one of the world's largest copper ore mines, moving ore extracted underground to an above-ground processing plant. The system, with a total installed drive power of 58 MW, transports crushed copper ore from underground storage bins to the surface along a 7 km underground tunnel that overcomes 1 km of vertical elevation. Once on the surface, the ore then travels along an overland conveyor that transports it the final 6 km to the distribution silo. The underground system, comprising two conveyors of about equal length, as well as the overland conveyor, has advanced gearless drive technology.
Conclusion The Utkal project demonstrates that, despite the increasing complexity of conveyor systems, access to the latest technologies supported by advanced design principals and expertise will result in a robust, reliable, and cost-effective overland belt conveying system. Additional factors that can play a major role in the success of a project like this one include taking an integrated approach to the system design and construction methodology for a seamless erection and commissioning phase. Furthermore, placing the focus on an owner/operator and supplier interaction can ensure that the designed system is not only fit-for purpose for its specific application and the project’s unique requirements, but that it is also best-integrated with upstream and downstream processes for overall system effectiveness.
Paul Harrison and Todd Swinderman, Martin Engineering, USA, emphasise the importance of thinking long-term when developing a conveyor system in order to maximise safety and cost-efficiency.
onveyors are among the most dynamic and potentially dangerous equipment at a mine or material processing site. Even though their safety and performance are critical to the operation’s success, the impact of their contribution to overall efficiency is often
unrecognised by management and workers alike. Operational basics of belt conveyor systems are too often a mystery to employees, who have little understanding of the hardware installed and the performance required from the components.
global mining review // April 2021
The knowledge gap is understandable. The attention of personnel at a mine or coal handling operation is centred on the processing of the company’s main product. The ‘care and feeding’ of belt conveyors – i.e. the adjustment, maintenance, and troubleshooting that make a huge difference in terms of safety, performance, and profitability – is typically outside of
Figure 1. This slide-out belt cleaner is engineered to be accessed safely and replaced by a single worker.
Figure 2. The track-mounted systems can be serviced quickly and safely, with no reach-in maintenance.
their expertise. It is not that they do not care about the conveyors, but the ongoing maintenance and service of these systems is often not part of their immediate focus or within their time constraints.
Protecting the most valuable assets Personnel are the single most important resource of any mine or industrial operation, and engineers and designers are incorporating greater functionality into designs that will improve safety. Standards continue to tighten, and the Mine Safety and Health Administration (MSHA) retains a strong focus on worker safety, driving the need for equipment designs that are not just safe, but optimised for safety – that is, designed with safety as a fundamental priority. At the same time, there is increasing pressure for continuous and ever-increasing production. In order to reduce hazards in the workplace, operators employ a variety of methods, from requiring the use of personal protective equipment (PPE) to installing the latest and safest equipment designs. When examining the safety of a system, improving efficiency and reducing risk can be achieved by utilising a hierarchy of control methods for alleviating hazards. The consensus among safety professionals is that the most effective way to mitigate risks is to design the hazard out of the component or system. This usually requires a greater initial capital investment than short-term fixes, but yields more cost-effective and durable results. Experienced engineers often recommend that operators contract an external company to examine system requirements and design new equipment around historical issues and the specific needs of the application, with an overall objective of Production Done SafelyTM. Before the drafting phase, designers should establish the goals of reducing injuries and exposure to hazards (dust, spillage, etc.) to increase conveyor uptime and productivity, and seek more effective approaches to ongoing operating and maintenance challenges. Designs should be forward-thinking: exceeding compliance standards and enhancing operators’ ability to incorporate future upgrades cost-effectively and easily by taking a modular approach. Examples of ‘eliminate by design’ are longer, taller, and tightly sealed loading chutes to control dust and spillage, or heavy-duty primary and secondary cleaners to minimise carryback. By using hazard identification and risk-assessment methods early in the design process, engineers can create the safest, most efficient system for the space, budget, and application. These designs alleviate several workplace hazards, while minimising cleanup and maintenance, reducing unscheduled downtime, and extending the life of the belt and the system itself.
Combining safety and productivity
Figure 3. The unique belt cleaner forms a 3D curve beneath the discharge that conforms to the pulley’s shape.
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To meet the demands for greater safety and improved production, some manufacturers have introduced equipment designs that are not only engineered for safer operation and servicing, but also reduced maintenance time. One example is a new family of heavy-duty conveyor belt cleaners, designed so the blade cartridge can be pulled away from the belt for safe access and replaced by a single worker.
The same slide-out technology has been applied to impact cradle designs. The systems are engineered so operators can work on the equipment safely, without breaking the plane of motion. External servicing reduces confined space entry and eliminates reach-in maintenance, while facilitating faster replacement. The result is greater safety and efficiency, with less downtime. Another example is a new belt cleaner design that can reduce the need for bulky urethane blades altogether, an innovative belt cleaning system that has received the Australian Bulk Handling Award in the ‘Innovative Technology’ category for its design and potential benefits. The patented design delivers extended service life, low belt wear, significantly reduced maintenance and improved safety, ultimately delivering lower cost of ownership. Unlike conventional belt cleaners that are mounted at an angle to the belt, the unique cleaner is installed diagonally across the discharge pulley, forming a 3D curve beneath the discharge area that conforms to the pulley’s shape. This novel approach has been effective to the extent that in many operations previously crucial secondary belt cleaners have become unnecessary, creating further savings with regards to belt cleaning costs and service time.
In most cases, electrical power is supplied only to the conveyor locations where it is needed, such as the drive motor, and is not typically available for general purpose use. In many operations, this lack of available power means that any monitoring of the conveyor must be done by technicians physically walking the length of the structure, which can be a difficult and time-consuming task on long systems spanning difficult terrain.
Power Another trend in large operations is a need for enhanced automation and monitoring. This includes tasks such as load sensing, belt tracking, cleaner tensioning, and lighting.
Figure 4. The generator can be employed on virtually any steel roller.
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A more efficient approach is to employ sensors to transmit important data from remote points to a central location where it can be monitored in real time and recorded for later analysis. However, the issue remains that intelligent monitoring systems for any conveyor system require power for extended operation. Due to the distances involved, cabled communication systems are not ideal, therefore wireless communication systems are more advantageous. Options such as solar are not well suited to the general conditions of a conveyor system, as monitoring devices are often required in an enclosed structure without access to sunlight, or for continuous operation during both day and night. A conveyor is driven by a multi-kilowatt motor, and this power is readily available system-wide in the form of the moving belt. The motors driving the belts are typically sized with a considerable power safety factor to account for parasitic loads, such as: rolls with damaged bearings,
Figure 5. The return on better design and quality is realised over the extended life and safety of the system.
tracking devices (which may work almost continuously), sealing systems, belt cleaners, and material changes that are required due to different moisture levels and variable loads. For these reasons, engineers have searched for ways to take advantage of the available kinetic energy of the moving belt to bring power to the specific places where sensors and other devices would provide advantages. In most conveyor designs, the belt runs on a set of rollers that provide support and guide the belt. The typical conveyor roller is a very reliable device, with key components, such as bearings, seals and the ‘steel can’, all well understood in the industry. Product designers theorised that they could draw power from a moving belt by attaching an independent generator directly to one of the rollers. In this way, they felt that power could be drawn from the conveyor without altering the structure of the system or affecting its physical configuration. Product engineers developed a design to accomplish this through the use of a magnetic coupling that attaches to the end of an existing roller. The outside diameter of the generator matches the diameter of the roll, but places the generator outside the normal belt line to avoid the heavy loads and fugitive material that tends to damage existing design attempts. The generator is held in a fixed position by the roll support system, but is not normally required to bear any of the material load. The reliable power supply helps bring a new level of sophistication to conveyors, allowing designers to equip their systems with devices such as weigh scales, proximity switches, moisture sensors, pressure switches, solenoids and relays, as well as timers, lights, and even additional safety mechanisms. Wireless communication can be used to transmit directly to a central controller, giving operators a cost-effective way to access data that has not been readily available in the past – and taking another step toward ‘smarter’ conveyor systems.
Low-bid process and life cycle cost Although the policy is generally not explicitly stated by companies, the low-bid process is usually an implied rule that is baked into a company’s culture. It encourages bidders to follow a belt conveyor design methodology that is based on getting the maximum load on the conveyor belt and the minimum compliance with regulations using the lowest price materials, components, and manufacturing processes available. Maximising the volume of cargo and minimising the price of the system usually means choosing the narrowest feasible belt, operating at the highest speed possible. This leaves little margin for error and in many cases results in chute plugging, excessive spillage, and reduced equipment life. When companies make purchasing decisions based on price, the benefits are often short-lived and costs increase over time, eventually resulting in losses. In contrast, when purchases are made based on lowest long-term cost (life-cycle cost), benefits usually continue to accrue and the costs are lower, resulting in net savings over time. Figure 6. Rather than meeting minimum compliance standards, conveyor systems should exceed code, safety, and regulatory requirements.
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The art: design hierarchy To safely maximise production, designers and engineers are urged to approach projects with a specific set of priorities.
Rather than meeting minimum compliance standards, the conveyor system should exceed all code, safety, and regulatory requirements using global best practices. By designing the system to minimise risk and the escape and accumulation of fugitive material, the workplace is made safer and the equipment is easier to maintain. Life cycle costing should play into all component decisions. It is important to be aware of specifications on project components that state ‘specific manufacturer name/or equal.’ Vaguely written ‘or equal’ specifications are there for competitive reasons and allow contractors to purchase on price without adequate consideration for construction or performance. Instead, buying on life cycle cost, or engineer-approved or equal and anticipating the future use of problem-solving components in the basic configuration of the conveyor, provides improved safety and access, without increasing the structural steel requirements or significantly increasing the overall price. It also raises the possibility for easier system upgrades in the future. The ability to accommodate future increases in capacity can also be included in the original design, expanding options and reducing future modification costs.
Conclusion Engineering safer conveyors is a long-term strategy. Although design absorbs less than 10% of the total budget of a project, engineering, procurement, and construction management services can account for as much as 15% of the installed cost of a major project. Additional upfront engineering and applying a life cycle-cost methodology to the selection and purchase of conveyor components proves beneficial. By encouraging the use of the hierarchy of controls at the planning stage, along with the design hierarchy at the design stage, the installation of an evolved basic conveyor can be achieved. The system will likely meet the demands of modern production and safety regulations, with a longer operational life, fewer stoppages, and a lower cost of operation.
Case study: Mexico A mine in north central Mexico was experiencing excessive spillage and dust emissions at the loading zone of its tower-mounted conveyor transporting raw gold, silver, zinc oxide, copper, lead, molybdenum, and sulfides. Despite installing various transfer and loading chute components from a previous supplier, workers found that dust filled the tower and chunks of raw material 2 – 3 in. (51 – 76 mm) in diameter were prone to spilling out from the transfer chute onto the stairs, partially blocking access to the area and creating a potential workplace hazard. Twice per month operations had to be disrupted for 12 – 24 hours so that a four to five person team could clean up the spillage and return it to the cargo flow. Clean-up and downtime raised the cost of operation and reduced efficiency. Technicians from Martin Engineering Mexico were invited in to assist with this problem. After a thorough inspection, the team were able to design a conveyor plan based on the principals of Production Done Safely. The plan addressed all aspects of the bulk handling process for properly guiding the cargo through the transfer chute. Impact cradles centred the material and promoted belt health. Slider cradles improved safety for external maintenance. The project also included skirting and dust bags to contain emissions and spillage throughout the settling zone. Strategically-placed tracking equipment aligned the belt along the entire path. Heavy-duty primary and secondary cleaners that slide in and out for service were installed at the discharge zone to reduce carryback and promote safer blade replacement. The entire system was designed with innovative safety features and ease of maintenance in mind. Each of the components work together to deliver a comprehensive bulk handling solution that promotes efficiency and a safer workplace. Following installation, fugitive material was significantly reduced and spillage no longer blocked access to the area. The air around the transfer point and throughout the tower was much clearer.
Figure 7. Raw bulk material drops onto a moving conveyor belt, creating dust and spillage.
Figure 8. The reconfigured conveyor controls emissions for improved safety and easier maintenance.
global mining review // April 2021
Ralf Hennecke, BME, South Africa, explores how integrating technology within drill and blast operations can help foster efficient and responsible mining.
he mine of the future is a safe, efficient and digitally integrated operation, within which systems deliver data in real-time for better decision-making. In order to achieve this, mining companies need alignment from all of their technology providers – including those in drilling and blasting. Indeed, its position at the front-end of mining operations means that drilling and blasting can have a significant impact on the efficiency of downstream functions, enhancing profitability and sustainability. With the rapid evolution of electronic and digital technologies over recent decades, the blasting sector has been able to leverage this progress in its quest to continuously improve the quality of blasts. Among the important trends facilitated by this technology journey has been the ability to plan and implement larger blasts – and to do this with high levels of reliability. This capability has been built on more than a few remarkable and complementary innovations, all dovetailing to ‘push the envelope’ of mining productivity. These advances include: software development for versatile blast planning; digital initiation systems for safe and complex blast timing application, coupled with electronic detonators for flexible and accurate timing; automated explosive pumping systems for quick and precise delivery; and scientifically developed bulk emulsion explosives for high energy.
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When these innovations – and more – are brought together by teams of blasting experts, steady improvements are achieved that are quickly reflected on a mine’s bottom line. The drive for larger blasts (where the mine’s scale and geology allows) has several benefits for an operation. The larger the blast, the less often blasting is needed; time is money, and the less time wasted by blast disruptions, the better. A large blast reduces the disruption of pit closures, when pit equipment must be cleared from the blasting zone and staff evacuated – followed by the specified delays for dust and gases to clear. Where mineral seams are covered by overburden, a large blast helps to accelerate the exposure of the ore so that mining can begin sooner.
Figure 1. The level of safety on mines is enhanced by these digital initiation systems.
Record breaking blasts In a recent record-breaking event for the use of electronic detonators in South Africa, BME initiated 4647 AXXISTM GII detonators in a single blast at an opencast manganese mine in the country’s Northern Cape province, beating its previous record of 3780 detonators, when a total of 1679 blast holes were charged with 359 t of BME’s emulsion explosive. The 4647 detonators delivered a blast that moved 635 000 t of overburden. Even larger blasts have been achieved elsewhere. At an opencast copper mine in Zambia, a world record blast using 7401 electronic detonators was achieved. The point, of course, is that these achievements were not accomplished out of the blue. They were made possible by decades of technical innovation. BME introduced its AXXIS electronic initiation system in 2010, and the company was able to achieve South Africa’s largest blast – 3111 detonators in a single blast at a nickel mine in Mpumalanga province – in 2011. Another record was set in 2014, with a blast of 3256 detonators at a local platinum mine. A few years later, the company’s technology broke a world record, firing 5665 detonators in 2683 blastholes at a coal mine in Australia. Mines will only conduct this scale of blasting when they are fully confident that the equipment and products will reliably deliver the promised results. In turn, this confidence can only be built on solid performance, where mines have seen the results from their technology providers – time and again. It is worth unpacking some of the key innovations that contribute to the safety and efficiency levels that mines can achieve today, and what this holds for the future.
Figure 2. Mines of the future focus on integrating technology throughout the whole value chain.
Figure 3. Modern detonators have revolutionised blast timing.
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The use of specialised software has become integral to blast planning, allowing blast engineers at mines to map out in detail the best way for the necessary area to be drilled and blasted. Survey coordinates and data from the blast area – including block shape, blast surface, and face profile – are pulled into the blast planning software, and a blast pattern is designed to suit the desired outcome. These specialised software products give designers the power to control and fine-tune certain aspects of their operations, such as: charge quantities, deck charging, and blast timing. The impact on the quality of the blast is not to be underestimated. For instance, in BME’s blast planning software, BLASTMAPTM, designers can create a blast and pattern virtually – complete with hole diameters to which they can add explosive and rock types. A 360˚ 3D rendering of the blast can then be generated, based on the charge, timing, and actual hole positions. They can also analyse the timing design using a blast timing simulator and predict vibration, fragmentation, and fly rock risk for the design. With greater pressure on mines to avoid any negative impacts on local communities, blast designers can simulate the best design to control vibration, air blasts, and fly-rock. Changes to parameters, such as delays and mass charged per delay, can make blasts safer and more effective. Digital technology also makes it much easier to share blast plans with experts who are not on site, raising the levels of confidence in the final design. The sector’s advances in these products allows mines to consider ever-more specialised blasts, making the most of
their ore reserves. There is multiple deck capability for blasting multi-seam or stratified rock, for instance, and for controlling vibration. Wave interference modelling also assists in optimising timing for either vibration control or optimal fragmentation. Beyond the improvement in technical performance, software also helps mines to manage the business aspects of each blast, reporting and communicating data on costs and quantities.
Automated drilling Mines of the future focus on integrating technology throughout the whole value chain within an operation. An example of this in the drilling and blasting space is the link between the blast planning phase and the actual drilling phase – where the capabilities of the blast planning software provide a bridge to the drilling function. Where drill rig manufacturers can automate and digitise their equipment, products such as BLASTMAP can communicate vital data like designed blast hole positions directly to the rig. This allows the rig, with the help of global positioning systems (GPS), to automatically locate and accurately drill the planned pattern. The blast pattern will include the x, y, and z coordinates of each blast hole, specifying how deep each hole will be and the angle at which it will be drilled – based, for instance, on what bench heights are required. These complex technologies include error correction features, to deal with instances where real conditions on the ground may require a blast hole location to be shifted slightly. The system needs to take note of any changes between the
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Charging up Final checks of blast holes deliver data that can be captured and uploaded in real time. There is an element of machine learning in the XPLOLOG system; as it collects data, it can predict and alert the user to any short holes or uneven floors – even predicting how this may affect the blast result. This capability feeds into mines’ strategic effort to minimise risk, in this case
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‘planned as’ and the ‘drilled as’ pattern and transmit them back to the blast design for updating. Here again, the industry has grasped the potential of digital tools to speed up information flow, so that mine management can follow progress in real time. BME has contributed to this with its XPLOLOGTM system, which integrates with BLASTMAP so that users can view, edit, and synchronise planned and actual captured data to a cloud database. These technologies are becoming more readily applicable at mine level as modern mines prioritise communication networks such as GSM or Wi-Fi, even on remote sites. For those involved in drilling and blasting, the process can be monitored remotely – allowing dipping, priming, charging, and stemming procedures to be more efficiently co-ordinated. In effect, this digitalises the pre-blast process, and by so doing it reduces human error, increases efficiency and oversight, and ensures reliable results. It should be noted that the application of this cutting-edge technology is not limited to countries where national infrastructure is well-supplied. BME has a large customer in a relatively remote part of Zambia, for instance, which is making good use of these systems to streamline their operations.
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reducing the chance of a sub-optimal blast. Any weakness in the drilling process can be highlighted and quickly addressed. By the time the charging of blast holes with explosive begins, the planning software provides a detailed and accurate picture of what each hole needs – including how many detonators per hole, what decking is required, and the specific amount of explosive needed in each hole. This has all been calculated according to the hole depth and the mine’s powder factor – in other words, the amount of explosive to break 1 m3 of rock. Among the digital innovations underway at this stage of the process is the equipping of charging trucks with devices to receive the data described above. This ensures that personnel can – with the help of GPS – quickly locate each hole and pump the exact amount of explosive specified in the final blast plan. Actual amounts pumped are also monitored and stored for later use.
Bigger, better blasting Underlying much of the progress in blasting practice has been the development and evolution of digital initiation systems – and their powerful use of electronic detonators. It is in large part the flexibility and accuracy in the timing of electronic detonation that has underpinned the steady growth in the size of blasts that are now possible. Ongoing innovations have also steadily lengthened the maximum firing time within which these detonators can be programmed, within a single blast. The latest generation of BME’s pioneering AXXIS digital initiation system, for instance, can deliver a blast of up to 35 seconds in duration with high precision. Extended blast times are vital for large blasts, as the essential control of air blast and vibration requires single-hole firing.
Avoiding the firing of multiple holes at once requires a level of accuracy achievable only with electronic detonation. Today’s systems allow for the programming of each detonation to within a millisecond of each other, even at a 35 second delay. With these levels of accuracy and reliability, blasting professionals can achieve finer and more consistent fragmentation in their blast results, as well as better control of the muckpile shape. This translates in turn into more efficient and economical loading, hauling, crushing, and milling – those critical functions that consume most of the energy in the mining process. By impacting on these functions, a quality blast can significantly reduce downstream energy consumption and improve a mines’ bottom line and carbon emissions status. The level of safety on mines is also enhanced by these digital initiation systems. The company’s latest AXXIS version incorporates a dual-voltage and dual-capacitor system, which allows programming, testing, and logging to be performed at a lower voltage than is required for firing the detonator. Sophisticated safety technology is built into BME's detonators to limit the risk of ignition from any external high-energy or stray current pulses when being used.
Conclusion In many ways, the future of drilling and blasting has arrived – or at least the way forward is clear. Mines are demanding an all-hands-on-deck collaboration with their technology partners, in order to foster efficient and responsible mining through digital innovation that is integrated across supplier platforms. Drilling and blasting technologies are proactively supporting this imperative by delivering greater value on their own account, but also by contributing to more transparency and real-time data access for the mine of the future.
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THE NEW PROMOS4.0 The world’s most advanced intrinsically safe automation system
For decades, Becker Mining Systems have been setting standards with modern and innovative solutions. Our automation systems are used in underground mines all over the world. In close cooperation with our customers, we have further developed our systems and adapted them to the needs of modern underground businesses. Our new PROMOS4.0 product line combines all the advantages of our previous PromosPlus and Betacontrol into a comprehensive fieldbus system: Ŷ 20 times faster Ŷ Fieldbus lines up to 4,000 m in length Ŷ Up to 96 devices each This ensures a futureproof and strong overall performance for the growing data requirements of modern underground operations.
For more information, scan the QR code or visit the following link: www.becker-mining.com/promos4
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