Global Mining Review - September-2021

SEPTEMBER 2021 VOLUME 4 ISSUE 6

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CONTENTS 63

03 05

Editor’s Comment World News

12

Creating A Favourable Future

Xavier Iraçabal, Saft, France, explores the growing advantages of battery electric power for underground mining vehicles and summarises key strategic choices in their charge management.

Anuj Mudaliar, Fact.MR, India, discusses new reforms proposed and implemented by the government for the mining industry in India, with a focus on regional and operational drivers, restraints, and opportunities.

18

31

41

51 55

83

87 91

Collaboration Is Key Sean Timmins, Orion, USA, considers five ways frontline collaboration is key to transforming mining operations.

99

Michèle Brülhart, The Copper Mark, Switzerland, examines the important role copper is playing in the global transition to a green economy, as well as some ways copper production itself can become greener still.

Storage That Lasts Rebecca Long Pyper, Dome Technology, USA, outlines how domes beat flat storage in longevity, strength, and capacity.

Going Green

Everyone’s Talking About Copper

Setting A New Pace Emily Loosli, Wingtra, Switzerland, identifies how drone mine surveys are setting a new pace for the industry, using a Canadian coal mine as an example.

95

Reaching Sustainability Goals

Putting Drones In The Picture Eloise McMinn Mitchell, Pix4D, Switzerland, asks the question: what is the point of using a drone?

Geoff Manley, Lubrication Engineering, Australia, explains how lubricant reliability can be improved by using a purpose-built lubrication storage and dispensing system.

Dr Niels Leemput, ENGIE Impact, Australia, outlines the four main strategies that mines can implement in order to set and attain achievable carbon goals.

58

77

Don’t Let Your Lubricants Lag Behind

Caitlin McKinnon, Motion Metrics, Canada, discusses the importance of decarbonising operations in the transition to green technologies.

Making The Right Choice Daniil Victorian, Doofor Inc., Finland, addresses how smart investment plans and the implementation of LEAN principles can help mining companies acquire the right mining equipment for them.

The Key To Grease Selection Mark Guenther, A.W. Chesterton Co., USA, advocates for the use of key performance indicators for grease selection in mining applications.

46

74

How To Choose The Correct Grease Pierre-Marie Maurice, Gautier Perrin, TotalEnergies Lubrifiants, Nicholas Thomas, TotalEnergies Oil Asia Pacific, and Tony Andreopoulos, TotalEnergies Oil Australia, review the importance of choosing the right grease for mining operations.

It’s All In The Drilling Ceren Şatırlar Balcı, Barkom Group Drilling Rigs and Equipment, Turkey, outlines the importance of the feasibility stage and field investigations of the drilling sector to mining geoscience.

Mining With Machine Learning Mikael Artursson, Minalyze Pty Ltd, Australia, considers why machine learning should be used in the mining industry.

36

69

Measure For Measure In Real Time Henry Kurth, Scantech International Pty Ltd, Australia, provides insight into the role of advanced real-time measurement in mineral processing.

Integrate To Communicate Christian Fimpler and Frank Kathmann, Eaton, explain how recent technological advances are making communicating underground more efficient and effective.

Responding Rapidly To Flotation Variability Jacques Bezuidenhout, Nalco Water, USA, addresses why flotation circuits have to continually improve and adapt to the changing needs across mineral processing operations.

27

67

Complicating Coal Markets Jake Horslen, Argus Media, UK, explores how China’s diplomatic spat with Australia is complicating the global coal market’s recovery from COVID-19.

23

Preparing For The Underground Electric Revolution

The Connected Mine James Trevelyan, Speedcast, UK, provides insight into how the Connected Mine can revolutionise the mining industry.

A Digital Two-Way Street Mark Roberts and Rahul Suhane, Maptek, outline how digitalisation is the key to unlocking the value of drill and blast, and how all sources of data can be tracked upstream and downstream and integrated into a single source of truth.

103 Precision Presplitting Optimisation Dr Anthony Konya and Dr Calvin Konya, Precision Blasting Services, review some new methods for precision presplitting optimisation.

108 Dry Backfill In Brazil Breno Castilho, Raphael Costa, Evilmar Fonseca, and Paschoal Cataldi, Hydro, Brazil, consider dry backfill as an innovative approach to tailings management in Brazil.

115 Limiting The Risk Of Tailing Dams Failure Rob Adam, AESSEAL, explores how re-evaluating the sealing methods on the pumps that feed slurry into the tailings dams is one way in which mining companies can better control water levels and mitigate against risk.

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Editor’s Comment T WILL OWEN, DEPUTY EDITOR will.owen@globalminingreview.com MANAGING EDITOR James Little james.little@globalminingreview.com SENIOR EDITOR Callum O’Reilly callum.oreilly@globalminingreview.com EDITORIAL ASSISTANT Jessica Casey jessica.casey@globalminingreview.com SALES DIRECTOR Rod Hardy rod.hardy@globalminingreview.com SALES MANAGER Ryan Freeman ryan.freeman@globalminingreview.com PRODUCTION Kyla Waller kyla.waller@globalminingreview.com ADMINISTRATION MANAGER Laura White laura.white@globalminingreview.com DIGITAL ADMINISTRATOR Lauren Fox lauren.fox@globalminingreview.com DIGITAL EVENTS COORDINATOR Louise Cameron louise.cameron@globalminingreview.com DIGITAL EDITORIAL ASSISTANT Bella Weetch bella.weetch@globalminingreview.com VIDEO CONTENT ASSISTANT Molly Bryant molly.bryant@globalminingreview.com GLOBAL MINING REVIEW (ISSN No: 2515-2777) is published bimonthly by Palladian Publications Ltd. Annual subscription (monthly) £50 UK including postage, £60 overseas (airmail). Claims for non-receipt must be made within four months of publication of the issue or they will not honoured without charge.

he statement, “environmental concerns are rising”, among others of the same ilk, formed the backbone of Dr Jumana Saleheen’s ‘Guest Comment’ that featured in the July/August issue of Global Mining Review.1 With the recent release of the latest Intergovernmental Panel on Climate Change (IPCC) report, these words now seem both prophetic, as well as a dramatic understatement.

According to the UN Secretary-General, António Guterres, the “IPCC Working Group 1 report is a code red for humanity. The alarm bells are deafening, and the evidence is irrefutable […] Global heating is affecting every region on Earth, with many of the changes becoming irreversible.”2 The Secretary-General pulled no punches to say the least, and the number of prominent names adding their voices to his in response to the report has only grown since its release. Once again, one of the loudest of these voices has been Swedish environmental activist, Greta Thunberg, who, in an interview with Reuters, has called for pressure to be placed on governments to fight climate change: “I hope this can be a wake-up call, in every possible way.”3 The response to the report from the world’s political leaders has included comments from both the British Prime Minister, Boris Johnson – who echoed Thunberg’s hope for the report to serve as a “wake-up call to the world” – and the US President, Joe Biden, who tweeted: “We can’t wait to tackle the climate crisis. The signs are unmistakable. The science is undeniable. And the cost of inaction keeps mounting.”4 The first speeches and verbal commitments have been made, and high-level talks will continue at November’s UN COP26 climate conference in Glasgow, Scotland, but the real question being asked is: what action is going to be taken – especially by governments and the industries producing the largest quantities of greenhouse gases (GHGs) – to safeguard the future of our planet?

It is undeniable that the mining industry is a significant emitter of GHGs. However, the urgent challenge of sustainability is not one that it is unprepared for. In this latest issue of Global Mining Review, there are no less than four technical articles outlining steps being taken to promote: the importance of decarbonising operations (Motion Metrics, pp. 51 – 54); strategies to attain achievable carbon goals (ENGIE Impact, pp. 55 – 57); “the global transition to a green economy” (The Copper Mark, pp. 58 – 61); and emission-free battery electric vehicles (Saft, pp. 63 – 66).

Make sure to check out all of this great content, as well as Fact.MR’s latest regional report, which discusses new reforms proposed and implemented by the government for the mining industry in India (pp. 12 – 16), and Argus Media’s special report exploring how China’s diplomatic spat with Australia is complicating the global coal market’s recovery from COVID-19 (pp. 18 – 22).

Speaking of COVID-19, with vaccination programme’s around the world beginning to have a noticeable an impact, borders are opening up and in-person events are finally resuming. The return of conferences and exhibitions, such as MINExpo, will no doubt be the mining industry’s own ‘shot-in-the-arm’, serving as a catalyst for new business opportunities and collaborations, and helping us all work towards building a brighter future for both our industry and our planet.

When the world’s largest mining event prepares to open its doors for business on 13 – 15 September in Las Vegas, make sure to visit Global Mining Review at Booth 1840 in the North Hall. We hope to see you there.

References 1.

2.

3.

4.

SALEHEEN, J., ‘Guest Comment’, Global Mining Review, (July/August 2021).

‘Secretary-General Calls Latest IPCC Climate Report “Code Red for Humanity”, Stressing “Irrefutable” Evidence of Human Influence’, United Nations, (9 August 2021).

‘Thunberg: “Massive public pressure” needed to galvanize climate fight’, Reuters, (9 August 2021).

‘U.N. climate change report sounds “code red for humanity”’, Reuters, (9 August 2021).

Palladian Publications Ltd, 15 South Street, Farnham, Surrey, GU9 7QU, UK t: +44 (0)1252 718999 // f: +44 (0)1252 718992 // w: www.globalminingreview.com

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WORLD NEWS GLOBAL ERG-led solution Re|Source strengthens partnership with Tesla

R

e|Source, a solution to trace responsibly produced cobalt from the mine to the electric vehicle, has acknowledged the progress made by Tesla in implementing a pilot project across its supply chain.

The pilot is being tested in real operating conditions, from upstream cobalt production facilities in the Democratic Republic of the Congo (DRC) to downstream electric vehicle productions sites. Multiple on-site pilots have already commenced in the DRC and Europe, and plans are in place to commence further pilots in Asia and the US later this year. The final pilot across the entire Tesla supply chain is expected to take place in 4Q21. The launch of the final industry solution is expected in 2022 and is being supported by boutique block-chain technology studio, Kryha.

The founding members of Re|Source, which include CMOC, Eurasian Resources Group (ERG) and Glencore, are joined by pilot partners Umicore and other supply chain participants. The solution is also being advised by a growing number of industry associates, including Norilsk Nickel and Johnson Matthey. Johnson Matthey’s participation is based on their experience in responsible sourcing.

The Responsible Minerals Initiative and The Cobalt Institute, two highly respected industry bodies with a deep understanding of the complexities involved in the cobalt supply chain, have also joined Re|Source as strategic advisors, supporting the implementation of world-class best practice standards across the pilot.

AUSTRALIA VECKTA awarded contract for Lynas Rare Earths Mt Weld energy optimisation

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n 4 May 2021, Lynas Rare Earths Ltd was awarded VECKTA the contract for distributed energy system (DES) modelling, sizing, and initial conceptual design for the Lynas Rare Earths Mt. Weld mining operation.

Lynas is the only producer at scale of separated rare earths outside of China and the second largest in the world.

The rare earths deposit in Mt Weld, Western Australia, is acknowledged as one of the highest-grade rare earths mines in the world and is a globally significant project for Australia.

In 2019, Lynas Rare Earths became a signatory to the United Nations Global Compact. As part of this

commitment and the development of the Mt Weld strategic resource, Lynas is dedicated to exploring and developing best in class energy solutions.

VECKTA will empower Lynas to accurately assess the energy options for the Mt Weld project, and then optimise them using VECKTA market data and the world’s leading DES design toolkit, XENDEE. VECKTA can then match specific project needs with the best suited constructors and equipment suppliers in the VECKTA market platform, and facilitate the procurement and contracting for transparent, consistent, and value adding win-win outcomes for all stakeholders.

LAOS Hexagon awarded project at Laotian gold mine

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exagon’s mining division has been awarded a fleet management project at Sepon gold mine in Southern Laos. The deployment will see HxGN MineOperate OP Pro implemented in trucks, excavators, and auxiliary equipment at the mine by the end of the year.

Sepon is an opencast gold and copper mine located in Savannakhet Province in Southern Laos. The mine is owned

and operated by Lane Xang Minerals Ltd, one of the largest gold producers in Laos. Since operations commenced in 2003, Sepon has produced 1.2 million oz of gold doré and more than 1 million t of copper cathode.

In 2020, Sepon produced more than 39 730 t of copper and 64 809 oz of gold doré.

The mine already uses Hexagon’s drill and blast solutions.

GLOBal mining review // September 2021

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WORLD NEWS Diary Dates MINExpo INTERNATIONAL 2021 13 – 15 September 2021 Las Vegas, USA www.minexpo.com China Coal & Mining Expo 2021 26 – 29 October 2021 Beijing, China www.chinaminingcoal.com Iron Ore Conference 2021 08 – 10 November 2021 Perth, Australia & Online www.ausimm.com/ conferences-and-events/iron-ore Mining Indonesia 2021 17 – 20 November 2021 Jakarta, Indonesia www.mining-indonesia.com Mines and Money London 01 – 02 December 2021 London, UK https://minesandmoney.com/london Future of Mining Australia 2022 28 – 29 March 2022 Sydney, Australia https://australia.future-of-mining.com Euro Mine Expo 14 – 16 June 2022 Skellefteå, Sweden www.euromineexpo.com

To stay informed about the status of industry events and any potential cancellations, visit Global Mining Review’s events page: www.globalminingreview.com/events

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September 2021 // global mining review

CHILE Antofagasta obtains the Copper Mark at Centinela

I

n line with the UN Sustainable Development Goals (SDGs), and after a voluntary evaluation process, Centinela has become the first of the Antofagasta’s mines to obtain the international Copper Mark, an assurance framework that certifies that the company operates under strict internationally recognised sustainable production standards.

Zaldívar expects to obtain the Copper Mark in September and the group’s other two mining operations, Los Pelambres and Antucoya, will shortly begin their own certification processes.

Inspired by the SDGs, The Copper Mark takes a comprehensive approach to sustainability and includes the verification of activities at the sites where copper is produced. To this end, it requires compliance with 32 criteria in five categories: business and human rights, community, labour and working conditions, environment, and governance.

The Copper Mark follows up its original certification with a further review of within one year, and then every three years thereafter to certify ongoing compliance with the criteria. In this way, The Copper Mark offers workers, investors, copper end-users, and communities a simple and credible way to verify sustainable practices.

RUSSIA ALROSA considers converting heavy-duty vehicles to

LNG

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LROSA is considering converting its fleet of supersize mine trucks and road trains to run in liquefied natural gas (LNG) and diesel mode. The switch would reduce opencast mining costs, increase operational efficiency and improve overall environmental performance, reducing emissions by one third. Annual savings are estimated to reach RUB 0.5 billion.

Currently, the core dimensions of the conversion project have been set ready for further evaluation and review. The project would see the transfer of more than 200 pieces of heavy machinery to LNG and diesel operation at the Aikhal and Udachny Divisions. It envisages the construction of an LNG plant in Udachny, as well as refuelling infrastructure that will include both fixed and mobile cryogenic filling stations.

According to experts, switching heavy equipment to using LNG and diesel at the same time would reduce liquid fuel costs by RUB 400 – RUB 500 million annually.

Moreover, the project will have a positive environmental impact, reducing greenhouse gas emissions by 20 – 30% in carbon dioxide equivalent.

The project’s pilot phase is currently being scheduled. Over a period of approximately 16 months, several types of diesel and LNG-converted equipment will be pilot-tested in real conditions. If all goes well, a decision will be made to build the LNG infrastructure and implement a full-scale switch to LNG and diesel operation for motor vehicles.

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WORLD NEWS CANADA Champion Iron signs LOI with Caterpillar for advanced drilling technologies

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hampion Iron Ltd has signed a letter of intent (LOI) with Caterpillar Inc. to implement artificial intelligence based advanced drilling technologies on Cat equipment at its Bloom Lake Mine.

The project will progressively implement a remote-controlled, semi-autonomous and fully autonomous Cat electric drilling fleet, utilising the technologies engineered, designed, and/or integrated by Caterpillar.

With Champion contributing its experienced workforce, and Caterpillar’s independent dealer, Toromont Cat, its aftermarket support, the collaboration will aim to optimise Bloom Lake’s operational productivity and reduce energy consumption, while demonstrating the capabilities of Caterpillar’s advanced drilling technologies.

A drill-to-mill strategy (D2M) is expected to be deployed based on a series of tightly integrated systems, driven by

Cat® MineStarTM solutions – designed to optimise the drilling, loading, and hauling processes. D2M is focused on delivering improved milling performance by supplying optimised mill feed, while contending with dynamic operational conditions.

Using real-time data, artificial intelligence and analytics, Caterpillar’s integrated technology will support Champion’s ability to assess the status of machines, technologies and material, in order to enable more timely and accurate operational decisions and consistent execution across Champion’s entire mining value chain. The goal of the collaborative effort will be to deliver a fully integrated D2M technology solution, powered by data connectivity and advanced analytics, to ultimately improve workflow between the mine and plant, providing a more efficient end-to-end enterprise process that delivers more consistent raw material for final product specification requirements.

BRAZIL Schneider Electric and AVEVA unify Vale’s mining operations

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chneider Electric and AVEVA are powering the unification of operations for Vale.

The combination of AVEVA and Schneider Electric software, technology, and mining domain expertise is providing Vale with the ability to integrate, centralise, and remotely monitor operations across its Mariana and Itabira complexes in Brazil.

Vale ranks among the top five largest mining companies in the world. Headquartered in Rio de Janeiro, the world’s leading producer of iron ore, pellets, and nickel employs a global workforce of over 170 000 people in 38 countries.

The Mariana Complex and Itabira Complex are two of Vale’s major iron ore production sites, located in Minas Gerais, Brazil. Together, the complexes are responsible for more than 75% of the production data from Vale’s Minas Gerais mining operations.

While primarily implemented to improve safety through remote operations, digitalisation is critically important to driving efficiency and sustainability in mining. Through the partnership, Vale can unify operations across multiple sites and upgrade its old system to one capable of remotely

8 September 2021

// global mining review

controlling all the diverse technologies operating across each mining facility. Crucially, the remote management solution enables Vale to have fewer professionals on site, increasing safety and reducing operational expenditures, while also vastly improving energy efficiency and, therefore, sustainability.

Vale chose Schneider Electric and AVEVA for the technological performance and visibility offered by their solutions. These provide an extremely high level of flexibility due to their vendor-agnostic nature, making it easy to integrate disparate technologies across multiple sites.

Schneider Electric deployed EcoStruxureTM Control Expert – Asset Link, combining AVEVATM System Platform and Schneider Modicon M580, to provide visibility and unify operations for Vale. The technology enables data to be integrated directly into the system, so Vale’s managers have granular insights without having to manually transfer any intelligence. By bringing this data together, Vale can now create a master operations centre and remotely manage everything.

This greatly improves operational efficiency and means less people are on site, providing a significant boost to safety.

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WORLD NEWS CANADA BHP approves Jansen Stage 1 potash project investment

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HP has approved US$5.7 billion (CAN$7.5 billion) in capital expenditure for the Jansen Stage 1 (Jansen S1) potash project in the province of Saskatchewan, Canada.

BHP CEO, Mike Henry, said Jansen is aligned with BHP’s strategy of growing its exposure to future facing commodities in world class assets, which are large, low cost and expandable.

Jansen is located in the world’s best potash basin and is expected to operate for up to 100 years. Potash provides BHP with increased leverage with regards to key global mega-trends, including rising population, changing diets, decarbonisation, and improving environmental stewardship.

Jansen S1 is expected to produce approximately 4.35 million tpy of potash, and has a basin position with the potential for further expansions (subject to studies and approvals). First ore is targeted in the 2027 calendar year, with construction expected to take approximately six years, followed by a ramp up period of two years.

Jansen S1 includes the design, engineering, and construction of an underground potash mine and surface infrastructure, including: a processing facility, a product storage building, and a continuous automated rail loading system. Jansen S1 product will be shipped to export markets through Westshore, in Delta, British Columbia, and the project includes funding for the required port infrastructure.

BHP anticipates that demand growth will progressively absorb the excess capacity currently present in the industry, with opportunity for new supply expected by the

late 2020s or early 2030s. That is broadly aligned with the expected timing of first production from Jansen. Beyond the 2020s, the industry’s long run trend prices are expected to be determined by Canadian greenfield solution mines.

In addition to consuming more energy and water than conventional mines like Jansen, solution mines tend to have higher operating costs and higher sustaining capital requirements.

At consensus prices, the go-forward investment on Jansen is expected to generate an internal rate of return of 12 – 14%, an expected payback period of seven years from first production and an underlying EBITDA margin of approximately 70%, given its expected first quartile cost position.

The company have previously acknowledged the US$4.5 billion (pre-tax) of capital invested to date has resulted in a significant initial outlay and that the approach would be different if considering the project again today.

The investment to date includes construction of the shafts and associated infrastructure (US$2.97 billion scope of work), as well as engineering and procurement activities, and preparation works related to Jansen S1 underground infrastructure. The construction of two shafts and associated infrastructure at the site is 93% complete and expected to be completed in the 2022 calendar year.

To date approximately 50% of all engineering required for Jansen S1 has been completed, significantly de-risking the project.

AUSTRALIA Bryah Resources commences diamond drilling at Windalah

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ryah Resources Ltd has announced the start of a diamond drilling programme at the Windalah Copper-Gold Prospect, which lies within the company’s Bryah Basin Project, located in central Western Australia.

In April 2021, Bryah completed eight reverse circulation (RC) drill holes, to depths of up to 350 m, to test below the significant volcanogenic massive sulfide (VMS) pathfinder element anomaly identified in earlier soil sampling and aircore drilling.

10 September 2021 // global mining review

Three RC drill holes intersected a broad disseminated to semi-massive sulfide zone with highly elevated antimony and arsenic, together with weakly elevated copper and gold values. This sulfide-rich zone is considered to be the source of the surface VMS pathfinder element anomaly.

The sulfide-rich zone targeted by this diamond drilling lies within moderate to intensely sericite-chlorite-pyrite altered mafic volcanic/volcaniclastic rocks of the Narracoota Formation, just beneath the contact with the overlying sediments of the Ravelstone Formation.

12 September 2021 // global mining review

Anuj Mudaliar, Fact.MR, India, discusses new reforms proposed and implemented by the government for the mining industry in India, with a focus on regional and operational drivers, restraints, and opportunities.

T

he mining industry in India plays a key role in the economy of the country. The sector is not only important in terms of its contribution to GDP, it also provides resources required by the massive Indian infrastructure and manufacturing sectors. Specifically, the country is home to some of the largest reserves of minerals and metals such as coal, titanium, aluminium, and more.

global mining review // September 2021

13

According to India’s Minister of Mines Pralhad Joshi, the country’s mining sector will play a key role in the government’s ambitious target of reaching a US$5 trillion economy by 2025. Joshi has also stated that more than 70% of Indian power generation can be attributed to coal.

Consequently, the mining industry is critical to the country’s energy security in addition to the agriculture and manufacturing industries.

Industry experts have opined that exploration activities in the country need to be incentivised with reforms such as the recent commercial coal block auction. Emphasis has been given to the importance of opening the sector to private players in stimulating the national economy.

The industry will notably contribute to employment and downstream industries. In an effort to resolve long-standing issues that have restricted the growth of the mining sector, the government of India introduced the Mines and Minerals (Development and Regulation) Amendment Bill, 2021.

Why are changes to mining regulations needed?

The diminishing contribution of the mining sector to the Indian GDP in recent times has been attributed by the Federation of Indian Mineral Industries to under-exploration and lower spending on exploration activities in India.

Favourable incentives from the state coupled with significant investments from private players will play key roles in the growth of the Indian mining industry for the foreseeable future.

The mining law in India has largely been left untouched since 1957, with notable changes only being made in 2015, 2016, and 2020 after the original Mines and Minerals (Development and Regulation) Act (MMDR Act) was introduced.

It provided a framework to categorise mineral and metal resources overseen by the state and central governments, including mining leases and methods to ensure the well-being of locals in the mining area. Amendments have become the need of the hour to keep up with modern day industry requirements.

India produces over 90 different minerals at over 1500 mining sites. The country is a global leader in coal and crude steel production. However, the sector contributes only around 1.75% of the national GDP. It is a country that is highly reliant on imports, despite a vast mineral reserve volume. Estimates project that only approximately 10% of the obvious geological potential of the country has been explored until now.

In March 2021, the Lok Sabha of India passed a bill to amend the MMDR Act, which sets stage for additional jobs in the sector, while allowing private players to bring in superior technologies into the mining sector. With the new regulations, India aims to improve on the potential of the sector to match that of resource rich countries, including Australia and South Africa.

employment rates in the sector – according to a statement from the Ministry of Mines, India is expected to witness an influx of approximately 55 000 direct and indirect jobs owing to the amendment.

The amendments are expected to attract domestic and foreign investments, in addition to the incorporation of safe, effective, and sustainable technologies in the sector. The government has already permitted 100% foreign direct investment (FDI) under the automatic route for the sale of coal. This also includes processing infrastructure for coal mining activities.

As the bill is passed into law, the mining industry is projected to become significantly industry friendly. Until now, only government agencies including CMPDIL, GSI, and MECL have been involved in mining activities. With the amendments, for the first time in India, private organisations will be allowed to take part in mineral exploration activities.

Importance of previous amendments Previous amendments to the MMDR Act between 2015 and 2020 have set the ground for the development of the Indian mining industry. For instance, leases were made transferable for minerals other than atomic minerals, coal and lignite, subject to the approval of the state government.

Until 2015, mining leases, reconnaissance permits, and prospecting licenses were allowed to be auctioned off to only those companies that were involved in production of iron or steel, power generation or coal processing, improving the potential for FDI. These restrictions were removed in the 2015 amendment, however restrictions still kept out bodies other than private entities with previous involvement in coal mining operations. Also, the lease period for non-metallic and metallic minerals has been extended to a duration of 50 years.

The need for central government approval for mineral concessions has been removed, while streamlining competitive bidding processes.

The MMDR Act was also amended in 2016 to allow the transfer of mining leases through routes other than auctions, which are used for captive consumption, in order to minimise obstacles associated with stressed assets with mining concessions.

The 2020 amendments changed the eligibility for coal and lignite blocks. Companies no longer require prior experience in coal mining to participate in auctions. Furthermore, companies not involved in power, steel, or coal-washing activities have gained the potential to access cancelled coal mines.

The transfer of licenses was made available for all minerals and also permitted with the changes announced in 2020.

Additionally, state governments were allowed to conduct advanced auctions of mining sites prior to the expiry of a lease, instead of waiting on the expiry date to take action.

Objectives of the amendments

Key takeaways from the 2021 amendments

According to the current Indian government, the amendments passed in 2021 aim to increase the contribution of mining to the national GDP by at least 1% from the current levels. In addition, the changes seek to bring in transparency in the mine auctioning process, while also improving on

The new amendments will bring about a number of changes that have the potential to revolutionise the Indian mining industry for years to come. Some of these include: Key provisions of the bill will allow the government bodies to extend mining leases to government-run firms

14 September 2021 // global mining review

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for a duration of 10 years, to improve on the efficiency of mine utilisation. Also, state governments can gain royalty payments to increase the duration of leases for Central Public Sector Enterprises.

The changes to the act will allow the central government to remove the distinction between captive and non-captive mines, by designating any facility as a captive mine. Such mines will allow the use of the facilities for any end use sector/industry.

Unlike before, leaseholders for captive mines are not restricted to sell their ore to only captive industries.

Now, captive mines can sell up to half of all their ores in the open market, provided that they pay additional charges to the government for the same. The government can allow sales to go above the 50% cap if necessary.

The District Mineral Foundation primarily operates to optimise the benefits for locals in the mining areas. The amendments will give the central government powers to direct the usage of funds of the foundation for the development of the locality.

The amendments have removed the need for the conventional non-exclusive license permit required by companies to reconnoitre an area to assess mineral potential.

The new act allows for only a two year permit for mining operations to start after the issuance of a license, which makes the reissuance of permits difficult owing to time constraints, while pushing for mines to become active faster.

The new amendments provide license clearances for long-term mining operations, before providing an opportunity for the lease to be transferred to a new bidder.

The government has also pushed amendments to keep mines from becoming inactive. Consequently, in a case where a state government is unable to auction off a mine, the central government can now step in to conduct the auction procedures.

New amendments have removed regulatory differences between non-captive and captive mines for statutory payments. Also, the National Mineral Exploration Trust is set to become an autonomous organisation.

Leading concerns on the amendments While the new amendments have the potential to substantially change the Indian mining scene, the bill faced opposition owing to a number of concerns, especially from the state governments – significant opposition has also been put forth by the Congress, who claim that the new bill affects the structure of the constitution.

Firstly, the auction process for mines in India have been conducted by state governments so far. State governments have raised concerns regarding the powers of the central government in managing the funding of the District Mineral Funds as per clause 10(i).

Also, the potential reduction of revenues from the state governments of India, owing to the fixing of royalties by the central government with regards to leases to government

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companies, is also a matter of concern. This is also an issue, where inactive mines may be auctioned off by the central government according to clause 14(iii).

Finally, the new laws are also being called potentially exploitative, owing to the risk of abuse and the impact on local tribal communities and the environment. While the reforms may prove economically beneficial, the anticipated rise in mining activities is expected to cause harm to already sensitive ecosystems across the country.

Furthermore, a number of vulnerable tribal groups currently reside in mining zones, and, as a result of the amendments, their residences are likely to be threatened.

Issues of relocation, rehabilitation, and compensation have to be considered by governments in the future. S.S. Ulaka, a Congress Member of Parliament, suggested that a joint committee should be formed to cut down on adverse effects of the amendments, including: tribal members from mining areas, officials from the Ministry of Tribal Affairs, and the Environment and Forest ministry.

The future of the Indian mining sector The projected boom in the mining sector from the amendments to the MMDR Act is expected to result in the metal, mineral and associated industries, which paves the way for further reforms in the future. With increasing exploration activities, the current high volumes of imports for materials such as copper, steel, iron, and coal in India are likely to reduce. This bodes well for the self-reliance initiatives that are preferred by the ruling BJP government.

Minister Joshi has stated that the government is seeking structural reforms including the standards of exploration for block auctions and open acreage licensing policy for allocation of mining rights in the country. Also, until now, companies had to take out exploration and mining licenses separately. However, with the new bill, this clause has been removed. Consequently, mining bodies can move directly from exploration to mining upon identifying a feasible site.

The amendments also clear the way for additional jobs in the sector, along with a greater potential for metal and mineral exports through domestic and foreign investments into associated infrastructure.

With the National Mineral Exploration Trust becoming autonomous, ambiguities arising from potential political differences can be minimised. The independence of the regulatory bodies will minimise biases improving resource utilisation. Efforts however, will be need to be made to improve cooperation between the state and central governments. Also care needs to be taken to minimise the environmental impact through the use of independent studies. The socio-political scene in India will play a key role in the developments of the industry, while meeting mineral security requirements of the country for the foreseeable future.

References 1.

2.

‘The Mines and Minerals (Development and Regulation) Amendment Act, 2021’, The Gazette of India Extraordinary, (28 March 2021), https:// mines.gov.in/writereaddata/UploadFile/mmdr28032021.pdf GUIMBEAU, A., JI, J., MENON, N., and VAN DER MEULEN RODGERS, Y., ‘Mining and Gender Gaps in India’, IZA Institute of Labor Economics, (November 2020), http://ftp.iza.org/dp13881.pdf

Jake Horslen, Argus Media, UK, explores how China’s diplomatic spat with Australia is complicating the global coal market’s recovery from COVID-19.

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OVID-19 inflicted an unprecedented demand-side shock on global thermal coal prices and seaborne trade in 2020, and the post-pandemic recovery has so far been just as tumultuous.

High calorific value thermal coal prices assessed by Argus Media hit decade highs in July. Seaborne NAR 6000 kcal/kg thermal coal prices reached US$151/t fob Newcastle, US$121/t fob Richards Bay, and US$135/t in the middle of July. This marks a dramatic turnaround since the economic impact of the pandemic peaked last summer, when those three thermal coal benchmarks sank as low as US$46.18/t, US$44.53/t and US$38.19/t, respectively.

Prices in global energy markets have staged a remarkable recovery so far this year, with crude, liquefied natural gas (LNG) and EU carbon allowances being just some examples

of markets that have not only clawed back last year’s losses, but overtaken their pre-pandemic levels.

Thermal coal Thermal coal has been swept up in this broader, bullish global sentiment, buttressed by fundamental drivers particular to the seaborne coal market. Last year’s La Niña weather phenomenon brought freezing conditions to northeast Asia and triggered a spike in seasonal power demand, while also creating unusually high precipitation in parts of Indonesia, Australia and South Africa, which hampered production at a time of peak consumption.

A string of non-weather-related supply disruptions have also kept the market tight, including production suspensions and protests at key mines in Colombia, train derailments

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and bottlenecks in South Africa, and shiploader faults at Australia’s key Newcastle thermal coal export port.

China’s ban on Australia imports Aside from the post-pandemuc recovery, the main issue disrupting the orderly functioning of global thermal coal markets in 2021 has been China’s informal ban on imports from Australia. This has driven a wedge between what would normally be closely correlated markets and changed the landscape of seaborne trade flows over the past 12 months.

Diplomatic tensions between China and Australia had been simmering prior to the first peak of the pandemic, but they came to a head around May 2020 after Canberra called for a probe into the origin of COVID-19. The Chinese government has since clamped down on imports of coal and a range of other commodities from Australia, in an apparent act of retaliation against one of its biggest trade partners.

Chinese imports of Australian bituminous thermal coal fell gradually from as high as 6.3 million t in April 2020 to zero in December and have been absent ever since, Chinese customs data shows.

At first glance, China’s thermal coal imports from Australia may seem almost inconsequential. China itself produced 3.8 billion t of all types of coal in 2020 according to official statistics, importing an additional 304 million t of thermal and coking coal from the seaborne market to supplement domestic supply and cater to its enormous demand. Of its total seaborne coal receipts – which represented around 8% of total coal supply in China – Australian thermal coal accounted for only 42.5 million t, or 1%, of China’s total coal supply.

But while it may seem like a rounding error within China’s overall coal supply mix, Australian bituminous coal made up a much more significant 59% of the country’s total bituminous coal imports over 2017 – 2020, and the current ban shows what an important staple the fuel has been for Chinese consumers in recent years. Key reasons for this include the specification and quality of Australian coal, the reliable availability of the fuel and its price and logistical advantages over other origins.

Figure 1. Chinese 1H21 bituminous coal imports (million tpm).

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Given that a significant proportion of China’s coal-fired generation is situated in the country’s southern coastal regions, seaborne imports are competitive in terms of both cost and logistics with domestically produced coal, which must be railed and/or shipped from China’s inner regions.

Regarding quality, the typical Australian thermal coal favoured by Chinese buyers is a NAR 5500 kcal/kg high-ash, but low-sulfur product, used for cement production or in a blend to create a feedstock for power plants. Non-Australian alternatives are available, but they usually come with drawbacks.

Non-Australian alternatives Indonesian coal is more plentiful but typically of a lower calorific value, with much of the country’s higher-quality grades already tied up in term agreements to other markets, such as Japan. Russia has limited Pacific-facing export infrastructure to support a significant ramp-up in supply, the fluorine levels in South African coal are typically too high to meet Chinese customs requirements, and imports from Colombia entail a much longer voyage to China than Australian or any other origin.

For these reasons, the increase in Chinese imports from its non-Australian partners has so far not been sufficient to fill the void created by Beijing’s informal ban. China's January – June 2021 bituminous coal imports from Indonesia and Russia averaged 2.4 million tpm and 2.5 million tpm, representing respective 19% and 80% increases from January – June 2020. The country has also received 573 000 tpm from South Africa, an increase from zero in 2020, and 362 000 tpm from Colombia, up from just 137 000 tpm in the first six months of 2020 (Figure 1).

In total, China has imported an additional 2.3 million tpm of bituminous coal from non-Australian partners compared with January – June 2020, offsetting only approximately 43% of the 5.3 million tpm it received from Australia in the first six months of last year.

Chinese power demand Replacing 42.5 million tpy of bituminous coal imports from Australia was always going to be a tall order for Chinese buyers, and domestic circumstances early in 2021 have made the task particularly challenging. Chinese power demand has grown at breakneck speed this year and, despite rising wind, solar and nuclear capacity, thermal power generation – the majority of which is coal-fired – remains critical to meeting growth in electricity consumption.

China's January – June power output grew by 15% on the year to 3858 TWh, according to the country's bureau of statistics. Wind, solar, and nuclear generation recorded impressive proportional increases of 14 – 30%, but in outright terms were a long way from satisfying the overall increase in electricity consumption. Thermal generation – 69% of which was coal-fired in 2019 – still rose by 16% or 394 TWh on the year as a result, to ensure

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that supply met demand. This corresponds to an additional 17.7 million tpm of NAR 5500 kcal/kg-equivalent coal consumption in 40% efficient power plants, Argus estimates.

China’s domestic coal production China has also struggled to sustain an increase its own domestic coal production in 2021, compounding the impact of weaker seaborne imports on overall supply availability in the country’s key coastal demand hubs. National production grew strongly in January – February, but slowed over March – May and was lower on the year in June, according to official statistics, with aggregate utility stocks 17.6 million t lower than a year earlier – 60.3 million t as of the end of June.

This supply crunch has underpinned a surge in domestic Chinese coal prices, which are now trading at a wide premium to international seaborne benchmarks.

Argus Media’s assessment of domestic NAR 5500kcal/kg Chinese coal averaged more than US$235/t fob Qinhuangdao at the height of winter in January, with the premium for domestic coal over imported tonnes averaging more than US$37/t in June. Prices eased as the winter weather abated, but the market began to strengthen again ahead of the peak summer cooling period, with the premium for domestic coal over imported tonnes averaging more than US$30/t in May. Prior to the ban on Australian coal imports, domestic Chinese prices were approximately US$20/t higher than those for imported coal during 2018 – 2019, with the spread ranging between US$11 – US$28/t (Figure 2).

The China-Australia impasse is also affecting the wider regional coal market in the Pacific. The most notable impact has been on the price of Australian NAR 5500 kcal/kg coal, which has established a wide discount to other benchmarks in the absence of regular Chinese demand.

The effect on the wider Pacific coal market With Australian coal shut-out of China, India has become a valuable outlet for some of the shunned volumes as the

relative weakness in Australian prices has made the origin unusually competitive against the country’s more typical suppliers. In January – May, Australian customs data shows that approximately 1.8 million tpm of thermal coal was exported to India, up from just 325 000 tpm in the same months of 2020.

Despite this, Australian exporters have not fully offset the China ban with an equivalent increase in shipments to other markets so far in 2021. This is partly because of supply constraints caused by inclement weather and broken shiploaders at Newcastle early in the year, but also due to the consequences of a decision taken by several producers to reduce their production guidance in the wake of extremely low prices in 3Q20. It is hard to imagine that China’s ban on Australian coal, with all the future uncertainty it has created, was not also a factor leading Australia’s miners to reduce their output, in order to avoid an oversupply of coal that they would not be able to sell to their usual customers.

There are also signs that the pool of non-Australian bituminous coal available to countries other than China has tightened, as Beijing’s ban has forced Chinese buyers to pursue coal from other corners of the market as an alternative to their usual Australian diet. China, Japan, South Korea, and Taiwan imported a total of 35.4 million t of bituminous coal from Russia, Indonesia, Colombia, and South Africa in 1Q20. That total barely changed in 1Q21, but China’s share rose to 15.2 million t from just 11 million t in the year before, with Japan and South Korea’s share falling by 2 million t and 1.8 million t, respectively.

Those countries can and have taken more coal from Australia in 2021, but this shift adds needless inefficiency to the flow of thermal coal around the region. Japan and South Korea are not typically big buyers of the NAR 5500 kcal/kg Australian coal that used to go to China, usually preferring to purchase a higher calorific value product to feed their power plants for technical reasons, which further complicates such a swap.

Conclusion

Figure 2. Chinese domestic vs imported thermal coal prices (US$/t).

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History shows that commodities markets and the traders, producers, and buyers that comprise them are able to work around issues that stop products flowing efficiently from where they are produced to where they are consumed, but this can often take time and inevitably saddles consumers with additional cost burdens.

China rode out extremely high prices last winter without backtracking on its Australia ban, which says something about its determination to persist with its current policy and means there is little to suggest that a quick return to ‘normal’ is forthcoming. The international Asian coal market may now be faced with an extended period of re-organisation as it seeks a new regional supply and demand balance.

Jacques Bezuidenhout, Nalco Water, USA, addresses why flotation circuits have to continually improve and adapt to the changing needs across mineral processing operations.

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lotation is at the heart of mineral processing. An optimised flotation circuit can positively impact mineral recovery while maximising grade. Mineral processing plants continue to face challenges with increasing variability in flotation, such as: ore body changes, shifting customer requirements, and more. Furthermore, mining companies are examining ways to make their flotation processes more efficient, looking at methods such as coarse particle flotation

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to drive operational savings and reduce energy use. As a result, the performance of each flotation circuit must be more agile than ever – continuing to improve and evolve to adapt to changing needs across mineral processing operations.

Flotation variability Sulfide flotation variability is a challenging yet constant reality that faces every mineral processing operation. Variability can come from a variety of outside influences, including: changes in the ore body itself, shifting customer demand or quality requirements, focuses on more sustainable operational

Figure 1. Froth within the sulfide flotation process.

Figure 2. An overhead view of a sulfide flotation circuit.

processes, and more. Mining companies face the dual pressures of responding to an increasing demand for higher production, while adapting to increasing variability that impacts their mineral processing operation. In addition, mining companies are challenged to achieve these demand increases while reducing their environmental impacts for a more sustainable carbon footprint.

Nalco Water, an Ecolab company and a global provider of sulfide flotation solutions, recognises that the challenges are not isolated to a specific region or market. With flotation specialists, on-site sales engineers and support laboratories around the world, the company continues to see variability as a primary challenge for mineral processing operations, across a variety of mineral processing environments and localities.

Nalco Water believes that two keys to adapting to variability are knowledge and speed. A rapid response to changes within a flotation process can help a plant maintain operations that are effective and productive.

A rapid response to flotation variability requires a mineral processing plant to be keenly aware of the chemical, mechanical, and operational factors that impact their process.

Performance monitoring of their chemical reagents, mechanical equipment, control systems, unique minerology, and more can help them mitigate the effects of variability on recovery. The company delivers a unique range of solutions to help customers monitor these factors. In addition to offering advanced frother and collector chemistry, the company takes a unique, wholistic service approach to monitor the performance impacts on a customer’s flotation circuit. The company has also recently launched a digital platform that uses innovative monitoring technology to deliver predictive, actionable insights that their technical service team can use to respond rapidly to changing flotation dynamics. The combined chemical, service and digital solution, called the Flotation 360, helps customers address changes expediently to maximise selective recovery, grade, and, ultimately, profitability.

Nalco Water flotation consultants, engineers, and laboratory personnel monitor a variety of performance indicators to measure the effectiveness of a customer’s flotation circuit, such as: froth characteristics, collector formulation, mineralogical characterisation, and more.

Emerging technology, such as a mobile bubble sizer measurement system, helps Nalco Water check cell mechanics and troubleshoot issues in real time. As a result, the company can help mineral processing plants implement process improvements quickly to ensure productive flotation performance.

While performance monitoring for the flotation circuit is key, Nalco Water also believes that a wholistic approach to the entire mineral processing operation is prudent and necessary.

Performance enhancements and operational changes in the flotation circuit can cause downstream effects if not carefully assessed before implementation. Nalco Water helps mineral processing plants to examine and evaluate these potential impacts to help mitigate risks from changes in the flotation operation.

Case study: North America Figure 3. An engineer servicing a plant on-site.

24 September 2021 // global mining review

For a copper mineral processing plant in North America, ore variability became a daily reality as the plant began to

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process a more difficult type of ore. The customer needed a solution that would help them improve overall recovery for more than one type of ore, specifically copper and molybdenum, which would help improve their total operational costs. The ore contained a sufficient grade of molybdenite to concentrate, making it even more critical to increase the recovery for both minerals.

Nalco Water applied a comprehensive approach to the challenge, surveying the ore minerology and operational conditions of the flotation circuit, as well as obtaining a deeper understanding of the plant’s metallurgical objectives.

Through extensive laboratory testing and a thorough plant trial, Nalco Water was able to design a tailored frother programme that improved metallurgical performance while reducing reagent consumption and minimising volatile organic compounds for copper sulfide and primary molybdenite. The technology also demonstrated the unique ability to capture ultra-fine molybdenite not recovered using traditional flotation reagents.

The optimised frother programme ultimately helped the mine to significantly improve both copper and molybdenum recoveries using the same dosage as the previous frother programme. As a result, the customer was able to improve their overall productivity and total operational cost.

Case study: Latin America For another copper mineral processing plant located in Latin America, ore variability was an influencing factor behind over-foaming events, which was ultimately impacting production capacity and total operational costs. Additionally, the customer had a number of sustainability metrics to achieve and wanted to find a solution that would help achieve their process efficiency goals. The customer needed a frother solution that would reduce over-foaming events in an effective way, driving reduced operational costs, increased productivity, and improved operational efficiency to meet their sustainability and business objectives.

The regional Nalco Water flotation team developed a study to reduce over-foaming events and optimise the frother blend. Through a robust process working with the customer’s metallurgical team, Nalco Water was able to develop an optimised frother formulation that produced significant productivity benefits, while also delivering on the customer’s sustainability and business performance indicators.

To build the solution, Nalco Water, plant management, and plant engineers collaboratively performed a market study on similar challenges and designed a unique laboratory screening process before ultimately developing the specialised frother formulation. The team performed in-plant trial testing to validate the benefits of the frother over an eight month period. During the trial, the Nalco Water technical team was tasked with reducing over-foaming events without impacting metallurgical performance. The trial period yielded several positive results, specifically reducing over-foaming events by 33% and their subsequent impacts on production by 44%. By reducing the challenges with over-foaming, the technical team was also able to mitigate health and safety risks for plant associates who were responsible for cleaning the plant after an

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over-foaming event. Moreover, the optimised frother blend allowed the plant to reduce overall consumption by 3%, resulting in cost savings and a more efficient process.

The optimised frother solution ultimately helped the customer achieve significant cost savings and realise key sustainability benefits. From a cost perspective, the customer ultimately saved over US$7 million in production losses from over-foaming events. The exponential return on investment (eROI) for the customer was US$2.4 million in overall savings.

From a sustainability perspective, the customer reduced their carbon dioxide emissions by 11 000 kg, due to the movement of fewer trucks to deliver frother reagent and over-foaming cleaning supplies. As a result, the customer has been able to maintain their desired production capacity while meeting their business and sustainability goals.

Sustainable flotation operations In addition to solving variability issues, many mineral processing plants are looking to make their flotation operations more efficient and sustainable overall, as outlined by the case studies. One of the drivers behind this shift is the sustained focus on environmental stewardship within mining, which has resulted in a specific focus on reducing carbon emissions across mining and mineral processing operations.

The industry continues to look for dynamic solutions that will help them recover more valuable minerals while using less energy. Coarse particle flotation can help mineral processing plants save energy while still recovering what they need for production. A finer ore grinding requirement uses more energy and requires more operational investment, and a coarser grinding requirement can help a plant reduce both its operational costs and its overall carbon footprint, while still maintaining optimal production.

Mineral processing plants are looking for innovation to push today’s boundaries on coarse particle flotation.

Nalco Water has observed a number of trends across its global customer base, including the use of larger flotation cells and adoption of digital technology to monitor and measure performance. Today, the company helps customers selectively recover relatively coarse particles (between 200 – 250 μm) and continues to develop solutions for where the industry is heading overall, which is to selectively recover 300 μm particles. As the industry evolves, coarse particle flotation will continue to emerge as a driving force for greater efficiency and plant sustainability.

Conclusion The challenges created by variability and a need for greater process efficiency will continue to persist. Mineral processing companies will need to continue to develop innovative solutions and work with agile partners to be able to respond to these challenges and meet an ever-growing demand for their products. It is recommended to work with a partner who can use a variety of chemical and digital monitoring solutions to ensure the continual performance of a flotation circuit.

From the partners’s perspective, the key is to have a strong service partnership that offers the support needed to implement process improvement projects in a way that maximises recovery and grade, while mitigating operational and environmental impacts.

Henry Kurth, Scantech International Pty Ltd, Australia, provides insight into the role of advanced real-time measurement in mineral processing.

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igital transformation in mining companies increases the visibility of mined ore and product quality to all stakeholders, located both on site and remote to the operations, so that aberrations can be identified and addressed in real time. Digitalisation of feed quality is now providing continuous, high quality data that many operations have come to rely upon.

Proven technologies can be used to improve process performance in mineral processing operations through real-time quality measurement of ore delivered to

the plant. Sensors used for blast fragmentation and in pre-concentration are well-proven examples. The key criteria are that analysers should be rugged, suitably designed for optimal measurement, reliable, easy to maintain and data should be easily integrated, readily available, representative, relevant, high quality, and beneficial. An effective due diligence process is essential.

Solutions, such as Scantech GEOSCANs, are now being implemented by global mining leaders as an integral part of their digitalisation strategy.

global mining review // September 2021

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Where to measure Measurements of ore and waste quality should generally be taken as early in the process as possible, although less representative measurement earlier in the flow may not provide better outcomes than more precise measurements further downstream. Measurement should be representative: so that the data produced has high integrity and relevance, and so that there is high confidence in decisions based on the data.

Experiences from many mining operations suggest that some technologies do not necessarily provide optimal outcomes. Surface analysis of mined faces, or loads in buckets, shovels or trucks, may be useful for ores that are generally considered homogeneous, but these are very rare.

For example, porphyry copper-gold ore has proven more variable than expected, so some sensors, such as surface analysis techniques applied to conveyed flows, are proving less effective than expected. Quality variability occurs in all commodities and this should be properly quantified before strategies are developed for control.

Conveyed flows represent the best opportunity to measure continuously and representatively over much smaller increments than a shovel or truck, as flow rates provide relatively consistent material presentation to penetrative measurement technologies. Technologies unaffected by particle size, belt speed and composition, segregation, moisture, and dust can provide very effective measurement after primary crushing. Variability is still

significant despite the mining, haulage, and stockpiling performed prior to that point (Figure 1).

Quality variability Material quality variability is a major challenge in process control. Despite mining, beneficiation, materials handling and blending, there is still considerable variability when materials reach the next stage in the process. Quality variability is well accepted as having a major impact on process performance and managing quality requires high quality, representative measurement systems. Rather than taking samples containing significant sampling error, the smarter solution has been to measure quality continuously, using appropriate technologies. Real-time measurement is an obvious method to achieve this, with typically short paybacks, sometimes a few months or weeks.

Physical sampling of coarse flows following primary crushing requires significant effort and cost expenditure to be effective, and assay results are not available until well after the material has been processed or stockpiled. Conveyed materials segregate due to particle size variation and vibration, with finer material migrating downward and coarser material over-represented toward the upper surface.

Moisture content can also be variable with depth and particle size distribution. Moisture can also cause materials to become sticky and lumpy, causing fines to coat and obscure coarser particles. Layering can be due to additional material loaded on top of prior material. Surface analysis techniques can exacerbate measurement bias by measuring material after segregation has occurred. These variations can be overcome through the use of well-designed and appropriately configured and customised transmission analysis techniques.

The impact of quality variability on process performance is well documented, and various work has been undertaken to understand how process recoveries can be affected. Figure 2 shows an example of copper metal recovery significantly reducing with increasing feed quality variability. This has major economic implications to operations and should be addressed by measuring and managing plant feed quality consistency.

Using data for improved control Figure 1. High variability displayed in porphyry copper-gold ore feed to process plant showing 30 second measurement data on 1000 tph conveyed flow.

Figure 2. Effect of increasing feed grade variability on copper metal recovery in a flotation circuit (after Codelco).

28 September 2021 // global mining review

Quality variability cannot be controlled if it is not measured. If it is not controlled, then it cannot be improved. Even the best performing plant can be improved through real-time measurement of ore quality.

Real-time data has many uses, particularly on plant feed material. Immediate responses include diversion of short conveyed increments (also referred to as bulk ore sorting), or changes to the feed blend to improve grade or quality consistency. Sepon Copper-Gold mine justified an analyser on copper grade, but substantially enhanced its benefits by then using iron, sulfur, calcium, magnesium, and manganese for acid-consuming gangue content monitoring for acid addition control in a leach circuit feed.

Measurement data is increasingly being used to generate additional benefits: Immediate feedback to mining operations helps confirm the grade delivered against the expected grade, so that schedules can be adjusted as needed in real time.

Feed forward control is used to identify quality parameters in real-time that affect processing, including: Hardness for mill feed rate adjustment.

Mineralogy and deleterious content for reagent dosing to optimise metal recoveries and reduce concentrate contamination.

Sulfide content for diverting ore to flotation while oxide is diverted to leaching, etc.

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Measuring and managing conveyed flows at full throughput rates has proven to be very effective where is has been implemented. Customised measurement solutions providing the quality of data required for optimal process control have generated the greatest benefits. Data is used concurrently for other data-based applications such as ore reconciliation, metal accounting, input to digital twins for performance simulation and optimisation, in addition to the immediate response activity of controlling feeders or diverters or changes in feed rate.

The application of high-quality representative measurement systems provides a new level of feed quality data visibility to all levels of the organisation at very low cost and for very large benefit. Most analysers integrate seamlessly with plant control systems ensuring data is easily accessed on site or remotely in real time. The availability of high-quality measurement data enables operations to respond decisively and efficiently to unexpected variations in quality, and to automate process responses where needed.

Technologies Composition measurement using high specification Prompt Gamma Neutron Activation Analysis (PGNAA), e.g. GEOSCAN GOLD, to measure the elemental composition through the full conveyed cross section continuously and representatively in real time, over short time increments, has proven exceptionally effective.

Individual elements are measured directly and independently, and these systems have been used for difficult mineral applications where analysis is required each 30 seconds of flow, as well as for ores where the trace elements are of interest – e.g. gold, platinum, etc.

Low specification systems needing 10 minutes or longer to produce reliable measurements are not useful for many applications requiring timely responses.

Through belt moisture (TBM), microwave transmission provides free moisture to precisions typically better than 0.5% moisture as a standalone system, or integrated with GEOSCAN. Fast neutron and gamma transmission measures hydrogen content directly with high precisions (usually better than 0.2% moisture) and can be used on materials not suited to the microwave technique, such as: coke, magnetite, or some metal concentrates.

SizeScan measures particle size distrubtion (PSD), volume and belt speed using 3D infrared camera technology and advanced algorithms to overcome segmentation software limitations on images from 2D cameras, and can be configured for foreign

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object detection. It is used in oversize detection and fragmentation analysis in dusty and humid environments where other systems have proved unsuitable, and does not require specific lighting. It has also been demonstrated to measure mass flow to within 1% of a nucleonic weigh scale. It is easily integrated with other sensors.

The aforementioned technologies provide results in real time directly to the plant control system and all analysis data is owned by the client with no accessibility issues. There are no cloud platforms to negotiate or ongoing costs to access data, which can be accessed on remote devices in real time.

Analysers should ideally possess the following: Remote access to minimise on-site time, but with remote support readily available when needed.

Installation during planned shutdowns and no interruptions to operations.

Non-contact with no wear components or consumable spare parts.

Immediate benefits to site.

A good example is that a 1 million oz + gold operation in North America increased ore throughput by 3%, within one month of installing a moisture analyser, by replacing a higher assumed average moisture content with actual measured moisture content, in order to remain within dry tonnage processing license limits.

The choice of technology should be carefully considered, as should the choice of vendor and product, as no two offer the same performance, services, or price.

Seek a vendor who: Has minimum ISO 9001 quality accreditation.

Has a history of success, innovative R&D, and their own analyser IP. Provides reference contact details, not installation lists – sales alone are not proof of performance.

Offers testing at no cost to confirm performance before purchase, as well as proof that it is achieved on site.

Listens and understands the problems at hand, in order to recommend appropriate solutions.

Understands relevant technologies in the market.

Has technical professionals recommending solutions on value, not salespeople selling on price.

Has a strong safety culture, with analysers requiring no external access restrictions during operation.

Has proven precisions over measurement time increments relevant for each application.

Offers customised solutions (specification and calibration), not one-size-fits-all.

Provides published papers, preferably case studies written by clients.

Takes responsibility for analyser performance – e.g. offers money-back guarantees.

Offers 24 months’ equipment warranties, and appropriate support response times.

Performance evaluation should follow international standards and any penalties for non-performance should be agreed prior to the purchase of the analysers. The rule

30 September 2021 // global mining review

of thumb is that analysers should be precise, fast and cheap, but that only two of these are available in reality.

Measurement precision on conveyed flows varies widely, even for the same technology. The differences in measurement performance, for example in a bulk sorting application, may be equivalent to over US$10 million/y in a contained metal feeding a mill.

Ongoing support Following initial factory QA acceptance, the installed analysers should have their field calibrations verified and performance expectations met before handover.

Installation support services should be offered to facilitate smooth integration of the analysers into plant operations, expediting their benefits. Analysers supplied by reputable vendors should achieve claimed performance shortly after initial commissioning and calibration. Online elemental analysers typically require calibration checks every six months. Any sampling required can be made manageable through good planning and need not interfere with normal production.

Ongoing technical support and regular analyser access, via remote connection or through site visits, should be offered as appropriate. Technical concerns should be resolved promptly. Well-designed and properly installed analysers should require minimal maintenance, particularly those without contact with the conveyor belt or material. Most analysers should perform better over time as they are fine-tuned to the material they are measuring. A vendor committed to further collaboration with a client to improve measurement capabilities, such as developing capabilities for more elements (at no added cost), can add significant value to a process operation. A good example is the retrofitting of a phosphorous measurement calibration to multiple iron ore customers at no charge.

Conclusion On-belt or through-belt analysers are available from many vendors and in different configurations. Publicly available feedback from customers is rarely provided, as many see successful implementations as a competitive advantage and failed implementations as an indication of poor due diligence.

Companies considering an analyser should ensure the correct solution is purchased. References should be contacted, as installation lists on their own do not indicate acceptable performance.

Higher quality measurements – i.e. precisions – enable tighter process control and improved outcomes, typically providing additional value worth many millions of dollars per year.

Customised analyser configurations and calibrations for specific applications produce the most useful, timely data possible to meet each client’s measurement requirements for effective process control.

Many of the world’s largest resources companies have adopted the technologies in various applications to not only improve sustainability, but also to demonstrate responsible resource management to their stakeholders.

Mikael Artursson, Minalyze Pty Ltd, Australia, considers why machine learning should be used in the mining industry.

M

achine learning (ML), artificial intelligence, and deep learning are all buzz words that have been frequently mentioned in the mining industry over the past few years. A question that often comes up in discussions related to data in the industry is: “Can ML do this?”. Very often, the answer is yes, but there is no point introducing ML just for the sake of it.

The first step is to define the problem that one would like to solve. Why should ML be considered in the first place? In general, ML could be set up to solve a well-defined problem in a fast, objective, and cost-efficient way. There is no doubt that ML could be used to solve almost any problem out there, although this is not without certain pre-requisites and it does not mean it is practically the best solution for just any issue.

Solving a real issue The issue that this article focuses on solving is a well-known issue related to classification of rock-types when logging lithologies. This is something that any geologist that has been logging rock core would be able to relate to. The task of logging and classifying rock types is very time consuming, subjective and iterative. The subjective nature of the task, in particular, means that results vary based on the person, their educational background and, of course, any previous experience. A classic saying is that if four geologists look at a piece of rock, there are at least five answers to what type of rock it is. This problem could escalate quickly, since there is a turnover of people in the industry and the new persons need to be calibrated towards the

global mining review // September 2021

31

task anew, which takes time and affects the quality and time of logging.

Attempting to solve this particular issue is not new, there have been several attempts in the past and present, but it generally comes down to what data is available and at hand for solving the problem.

The approach In order to embark on the ML journey, the primary pre-requisite is data, and lots of it. To complicate things further, this data should also preferably be consistent, representative and, most importantly, well understood and classified. In this case, consistent means that the data is acquired in the same way and of the same quality. Take a photograph, for example: the photograph in this case should be taken using the same light source, the same focus, and in the same format and resolution.

One approach in solving this specific task has been related to using photographs of the rock. However, a lot of the information that is important in deriving the class of a rock is a function of both visual (i.e. textures and colour) and compositional (i.e. geochemical or mineralogical) features in the rock, which might be hard to discern from one type of data alone.

Another approach has been to use compositional data, but this has generally been based on too few sample points, or a spatial resolution that is not high enough to avoid sampling over boundaries or to pick up shorter intervals of distinct features as they would be diluted. Another issue with depth related data is that it is hard to properly match where a certain dataset is coming from in relation to the rock itself.

The approach that this article will focus on combines a wider set of data that covers both visual and compositional aspects of the rock, that is acquired at high-resolution, standardised to a consistent quality, and correctly depth related.

Getting the ones and zeroes In 2014, a new core analysis and digitalisation instrument called the Minalyzer Core Scanner was released onto the market, defining a new category of industrial, high-throughput instruments. It was designed to address many of the data acquisition issues addressed previously in this article (Figure 1).

It is a proprietary and patented system that acquires high-resolution photography, alongside a LiDAR that maps the topology of the core tray and sample in 3D. This enables for the detailed, fast and non-destructive elemental analysis of core samples through X-ray fluorescence (XRF) analysis, with results available directly on site or online within hours, rather than weeks or months.

At the point of release, ML in this context was not generally discussed and very much at a concept state. Over time, the data has proven to work very well as a base for ML, primarily due to its consistent nature.

It is important that instrument manufacturers and data providers engage in and understand common ML algorithms and workflows, in order to prepare the data in such a way that it is fit for purpose for the ML exercise, as well as being able to seamlessly deliver and present the data to the algorithm. Data collection and preparation often amounts to up to 80% of the data scientists time in reaching a result from ML.1 The type of operations necessary for any numerical data is to make sure the data is ‘clean’. Clean data in this context refers to mean data that does not contain odd characters and has been normalised. With regards to a photograph, cleaning the dataset might be compared to cropping the image to a consistent resolution and size, ensuring that non-retrievable data is coloured in a consistent colour, to name but a few examples. An example of a core tray that has been divided in several intervals with associated geochemistry can be seen in Figure 2.

The ground truth

Figure 1. Minalyzer Core Scanner.

Figure 2. Core tray with intervals.

32 September 2021 // global mining review

To train a ML model, a geological log needs to be produced classifying each high-resolution interval along a set of drill holes.

These classifications need to be based on the geochemical interval data set derived from the XRF elemental analysis, as well as the corresponding core photograph from the interval.

An automated log can then be generated (Figure 3). To achieve this, the high-resolution interval geochemical and core photography data of a new hole containing the same/similar rock types was presented to the deep learning neural network that was trained in the ML model.

The different rock types have been visualised as different colours along the X-axis (downhole). For each

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interval, the probability of the other rock types is displayed of a 100% total probability in the Y-axis.

It is apparent that the training of a ML model is one of the most important steps in reaching a good and relevant result. It is a slow process and that should be the case, especially when determining and establishing the so called ‘ground truth’. The ground truth is the step where a geologist classifies each distinct sample, and it is the quality of this exercise that will determine the outcome of the training and future prediction of rock types in unseen drill holes.

Another aspect that makes the process of training slow is the hardware required to perform the training, coupled with the number of ‘epochs’ or training iterations. The old saying ‘practice makes perfect’ very much applies to ML as well. The more iterations one uses when training, the better the training will become until a limit is reached, where one might be overtraining both the numbers of repeats and the number of inputs or variables.

A good rule of thumb that would apply in any teaching is ‘if the teacher is confused, then the students will be confused as well’. By not classifying the dataset correctly, the algorithm will be confused, consequently affecting the end prediction.

The main benefit of having trained an algorithm is the possibility to utilise it for generating a first pass lithological log, fully automated and at speed – the example log in Figure 3 took approximately just 50 seconds to generate, as opposed to a week by traditional means.

Subjectivity remains an important factor to keep in mind when evaluating an automated log, such as one generated by an ML algorithm. As an example, say the prediction made in the Figure 3 log reached an accuracy of 79%. One might say that 21% of the data in the downhole classification is wrongly classified.

However, others would argue that the algorithm is likely to be correct in most of the samples that have been deemed wrong, in comparison to a human generated lithological log. The truth is probably somewhere in between. One contributing factor is likely the resolution or detail to which a geologist has logged the core, but undoubtedly human subjectivity does play part as well.

Integrating into the workflow The most important part of integrating ML is the full implementation of the algorithm into existing workflows. It is a difficult transition to make, mainly due to the nature of change and people’s natural reluctance to change, but it returns significant rewards.

In addition to this, there is also another aspect to consider: the workflow and how the solutions fit in. ML must be implemented in such a way that the overall throughput and flow of core processing is not affected negatively. Therefore, the data acquisition, followed using the algorithm and the subsequent

Figure 3. Automated lithological log.

34 September 2021 // global mining review

manual logging based on the first pass automatic log, must be in symbiosis and balance out. Depending on the amount of drill rigs operating on site, the appropriate data acquisition instruments needs to be balanced. The algorithm is most likely never going to be the bottleneck.

Benefits Going about implementing a ML-based automatic logging algorithm for the task of lithological logging at a mining operation has several benefits.

The first benefit is that before the development of the algorithm and the underlying knowledge of the deposit takes place, the data acquisition will likely have to be improved – both in terms of the way and speed at which the data is captured, but also the quality and density of the data, which will help to make it meaningful for the algorithm. The users of the data will also find that the increased quality and standardisation will aid them in any manual processes.

The second benefit is that the knowledge around the deposit and which input variables are important for fingerprinting the different rock types increases, as part of the journey entails a more detailed logging and classification of the rock types for training purposes. To this point, any confusion between rock types makes it more apparent where to focus any further deeper analysis aiming to better distinguish and differentiate between rock types.

The third benefit is the most obvious, and constitutes the goal of the exercise itself: making the task of lithological logging faster, more objective, and less iterative. ML makes the task faster by using a computer to process large amounts of data through a trained algorithm; objective since the decisions are based on trained and validated data; and less iterative since the drill core is likely to not have to be re-logged after subsequent analysis.

Additional benefits include less operational sensitivity to turnover of employees, since training can be faster and based on more standardised logging. The logs could possibly be used to improve the selection of samples for further analysis, thus saving on time and spending related to sample preparation and, ultimately, the assay budget itself.

Conclusion Considering the benefits mentioned in this article, the original question of 'why should ML be used in the mining industry?' changes to 'why not use ML in the mining industry?'. If one has the data, why not put it to good use?

References 1.

‘Why data preparation is an important part of data science?’, ProjectPro, (2021) https://www.dezyre.com/article/why-data-preparation-is-animportant-part-of-data-science/242, [Accessed 30 June 2021].

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36 September 2021 // global mining review

Pierre-Marie Maurice, Gautier Perrin, TotalEnergies Lubrifiants, Nicholas Thomas, TotalEnergies Oil Asia Pacific, and Tony Andreopoulos, TotalEnergies Oil Australia, review the importance of choosing the right grease for mining operations.

H

igh and low temperatures, harsh conditions, heavy loads, high and low speeds, water, shock loads and vibrations, and many other conditions are experienced by mining operations around the world.

This means, for the mining industry, greases are one of the key elements to ensure reliability of critical equipment and significant advantages can be gained by choosing the correct grease.

Grease in mining Mining equipment can be divided into two categories: mobile and fixed plant. This means that greases are expected to lubricate many different types of components, such as bearings and open gears.

Depending on the conditions and application, the choice of the right grease is crucial to keeping equipment running reliably for extended periods of time.

TotalEnergies has a full range of greases available for mining operations of all types. The greases range from standard lithium based EP NLGI 2, to specialty open gear greases. This article will highlight the different components that contribute to the composition of a grease and the impact of the process and formulation on the final product.

Grease development In the last three years, TotalEnergies Research and Development Centre has explored and tested hundreds of formulations of mining greases. The mining industry might seem like a mature market with proven solutions for equipment lubrication, however this is what Kodak thought in 1975 when digital photography appeared on the market. They thought hard printed film photography was the most proven and efficient technology and that there was no need to continue innovating.

Likewise, mining operators are still challenging greases that have been in use for decades and are constantly asking questions such as: Are lithium complex greases really needed for mining equipment?

Is 5% molybdenum disulfide (MoS2) content really necessary to protect the equipment or are operators paying for a useless add-on?

What is the real influence of the National Lubricating Grease Institute (NLGI) grade on performance?

The absolute truth, which every grease manufacturer would agree to, is that mining greases are full of compromises.

global mining review // September 2021

37

Unlike multipurpose applications, mining equipment is subjected to extreme loads, shocks, vibrations, dust and

Figure 1. Performance of two different mining greases formulated in the TotalEnergies laboratory.

Figure 2. Four-ball weld testing results on two different mining greases, as tested by Total Energies laboratory.

Table 1. Four-ball weld test results

water contamination, and huge temperature variations.

Because of slow movement, hydrodynamic lubrication is almost never achieved, meaning that metal to metal contact is almost inevitable. Furthermore, different circumstances require grease-based lubrication to be delivered in different forms. As an example: in winter, greases need to be pumped effectively from service trucks, through 20 m long pipes; and in summer, they are expected to stay in place in pins and bushes or on girth gears in 40˚C conditions. For this reason, many mining companies use different products during the winter and summer seasons. Occasionally, even three different NLGI grades of greases may be used.

The problem is that the perfect grease does not exist and when a choice of thickener, base oil and additives is made, it will not achieve full performance for every criterion – as seen in Figure 1, which shows two mining greases formulated in the Total Energies laboratory. These criteria are the translation of requirements for equipment protection and effective grease delivery.

To illustrate the compromise that must be made, Figure 2 shows each parameter placed opposite of its counterpart.

For example, by improving adhesiveness by adding heavy polymer or increasing soap content, the pumpability will decrease accordingly. Certain polymer technologies can help to reduce the counter effect on pumpability, but they do carry a high cost and may have other limitations.

Extreme Pressure (EP) additives will also compete with anti-wear additives on component surfaces. For example, adding too much EP additive to achieve maximum protection will decrease the effect of the anti-wear additive, as is shown in Table 1.

For this example, the Load Wear Index (LWI) is also an important parameter to review when looking at four-ball weld load results. LWI is a measure of the relative ability of a lubricant to prevent wear under applied loads.

TotalEnergies has observed greases that do not pass 500 kg four-ball weld load but then do not weld at the higher 620 kg. This ‘hole’ in the EP performance can be spotted by looking at LWI results that will be relatively low.

Soap content

Four-ball weld load – ASTM D 2596 (EP performance)

Four-ball wear scar – ASTM D 2266 (Anti-wear protection)

Grease A

800 kg

0.71 mm

Grease B

620 kg

0.58 mm

Although the amount of soap contained in the grease never appears on the technical data sheets, it does however have an enormous influence on the NLGI grade, pumpability and adhesiveness, as well as other characteristics. The percentage of soap is directly linked to the consistency of the grease, i.e the NLGI grade. Figure 3 shows the typical quantity of lithium soap used for manufacturing different grades of straight lithium, EP grease.

Manufacturing process

Figure 3. Percentage of mass of lithium soap in the grease.

38 September 2021 // global mining review

Manufacturing a grease is a lot more complicated than blending a lubricant, even engine oils. Just like baking a cake, timing is everything. Many grease manufacturing plants try to reduce their production time to maximise volume output, but every respected chef in their kitchen will tell you that not heating and cooling effectively can have a significant effect on the overall quality of the final product.

Similarly, for greases, the same rule applies to get the perfect reaction between the alkaline (lithium, aluminium,

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HYDRANSAFE HFC-E 68

Fire resistant

Mechanical protection Biodegradable Non-toxicity

New generation hydraulic fluid TotalEnergies has introduced the fire-resistant HYDRANSAFE HFC-E hydraulic fluid that not only reduces fire hazards in underground mining but can also deliver higher equipment reliability.

HYDRANSAFE HFC-E boasts four key features of hydraulic fluids: fire resistance, highly improved wear performance, non-toxicity and biodegradability.

lubricants.totalenergies.com

ms.industry.lub@totalenergies.com

TotalEnergies Industry Solutions

calcium, etc.) and the acid components. For this, the temperature needs to be controlled down to within +/- 2˚C and the cooling rate must be managed minute by minute, for every batch. TotalEnergies is one of the world leaders in grease manufacturing and pioneered the Calcium Sulfonate Complex grease, namely the CERAN range.

Compatibility Unfortunately, no additive can protect a grease against cross-contamination. In the mining industry, aluminium greases are the most common types of greases for girth gears (TotalEnergies COPAL OGL and GRAFOLOG H range) as they have a great rheological behaviour, ensuring good pumpability and good adhesiveness. On the other hand, lithium-based greases are used predominantly in pins and bushes and bearing applications (MULTIS MINE range).

The issue is that these two thickener types of grease are completely incompatible. So, what does happen when incompatible greases are mixed? Table 2 reflects what happens to some of the key properties of greases when mixed with an incompatible grease type. Indeed, Table 2 shows that the grease resulting from mixing both greases together is completely out of line with specifications. This is why it is crucial to have a dedicated field engineering team, such as that which TotalEnergies has implemented for its mining customers, to help and guide clients on the right path to effective grease lubrication.

with a 460 cSt (when tested at 40˚C) base oil that have better EP performance and anti-wear protection than a 680 cSt base oil grease. Most of the company’s formulations are a blend of mineral and highly refined base oil, but synthetic base oils are also used mainly for arctic product applications, as well as locations where high temperatures are experienced for extended periods.

TotalEnergies is also currently working on bio-based formulations with excellent performance to fit the higher demand for such products.

What about the content of solid additives?

Here again, less is not more, but what is enough is important. MoS2 prices are skyrocketing and this is making the industry review the 5% MoS2 content imposed by certain manufacturers.

A recent internal study on TotalEnergies MULTIS MINE lithium grease showed that with the right mix of EP and anti-wear additives, 3% of MoS2 is largely sufficient to ensure a result of 620 kg on the four-ball weld load test – ASTM D 2596 – and to keep the wear scar low.

Adding more than 4% allows grease to potentially reach 800 kg, and could be considered an ‘extra safety layer’.

However, this is over engineering, as this level of performance is not required in this type of heavy-duty mining equipment.

Base oil

Performance

The viscosity of the base oil used in the formulation also plays a role in the performance of the grease, but it should not be the main criteria for selection. Yes, high viscosity protects against low speed and high load conditions, but TotalEnergies’ research centre also has formulated greases

Performances that are mentioned on a technical data sheet (TDS) are not always directly transferable to the equipment.

For instance, if the automatic greasing system is injecting grease in the application twice as often than the necessary amount, long lasting EP and anti-wear protection are irrelevant. The grease will be replaced long before these additives are depleted.

Table 2. Testing results when mixing thickeners Aluminium based grease

50/50 mix of both greases

Lithium based grease

Penetration 371 after 60 strokes

412

280

NLGI grade

0

00

2

Dropping point (˚C)

195

156

201

Figure 4. Weld load vs Moly content.

40 September 2021 // global mining review

Case Study There is a common saying among grease customers, “it is better to over-grease and be on the safe side”, but this is not entirely accurate. TotalEnergies advises its customers on how to use the right quantity of grease depending on their circumstantial constraints – promoting greater efficiency in grease usage, whilst maintaining productivity. The benefits of this practice are illustrated by a recent example of the company being able to facilitate a decrease in the number of pins and bushes utilised by a major Australian mining customer by 25%, in addition to a decrease in grease consumption. The customer had been used to seeing grease overflow out of components when they were greased with their current product, and it was initially a challenge for them to accept TotalEnergies’ proposal. However, demonstrations showing that the new grease would stay in place longer in the application, thus providing a better level of protection with lower grease consumption, proved convincing.

The best choice and use of a grease can only be made with a strong maintenance programme that will follow closely the wear of the equipment and detect any over or under performance of the set-up over time.

Mark Guenther, A.W. Chesterton Co., USA, advocates for the use of key performance indicators for grease selection in mining applications.

I

n the mining and mineral processing industry, as well as almost every other industrial operation, proper lubrication is the uncelebrated hero of reliability.

From raw material to finished final grade ore, plant reliability and profitable operation relies on equipment uptime. Using the wrong grease will shorten equipment life, increase downtime, and cost money. In mining, this impacts everything from crushers and conveyors to sag and ball mills, apron feeders to electric motors and loaders.

Beyond just selecting the correct viscosity and NLGI grade, operators will ideally select the correct grease by using key performance indicators (KPIs) matched to specific application demands.

How well does the lubricant withstand shock load, oil separation, and shear thinning? Does the grease prevent water ingress? Will it passivate the ferrous substrate to reduce pitting corrosion to bearing components? These are attributes that will not necessarily be found by simply selecting Lithium EP #2 grease.

Determining requirements In general, step one is to identify a comprehensive list of essential technical and non-technical requirements, and can include: Considering the type of system equipment, operating conditions, application methods, and environmental conditions.

Finding out whether an original equipment manufacturer (OEM) or industry standard indicates quantifiable performance pre-requisites.

Determining if these standards are applicable to a ‘real world’ service condition.

Using simulations, models, software, and industry knowledge to estimate both qualitative and quantitative requirements.

Complying with federal, local, and company-specific regulations that can impact the transportation, handling, storage, disposal, and legality of specific greases.

Choosing a grease formulation Industrial greases can be formulated to achieve certain performance attributes measured and documented by ASTM, DIN ISO, and other standard tests. Lubricant manufacturers must conduct these tests to classify the greases they offer. These tests are fully documented and

global mining review // September 2021

41

characterised on the grease manufacturer’s technical data sheet (TDS). If KPIs are not present on a manufacturer's TDS, seek alternative suppliers that fully characterise their grease, in order to best support good decision making (Table 1).

Equipment bearing grease – performance data comparison The next section of this article will take a look at how selections can be made based on three equipment types critical to the mining industry.

Comparing test standards in the buying process

Conveyor systems

Manufacturers’ test standards should be compared in order to select the best grease for a specific mining application (Table 2).

It should also be borne in mind that the selection of proper base oil viscosity, NLGI grade, and thickener selection based on bearing size, RPM, and pumpability requirement will have already been made.

The column marked ‘optimised’ shows the target rating for specific test standards. Columns three to five show different common technologies in the mining industry. Operators’ own brand contenders should be inserted there for comparison.

The bearings on conveyor systems handle coarse rock or large heavy raw ore and, as a result, are subject to excess shock, load, and vibration. A critical feature of a high-performance grease for this application would be maximising the four-ball weld load and four-ball wear of the lubricant. This will help ensure that the bearings are adequately protected from shock load, vibrational load, and wear during operation. On sag mill feed conveyors, for example, tension, head, and tail pulley bearings might benefit from a grease optimised to protect against transient loads and vibration.

Table 1. Critical list of tests specific to mining application challenges

Electric motors

Test standard

What it measures

How the test is conducted

ASTM D2266 Four-ball wear

Wear preventative characteristics of lubricating grease (four-ball method)

The average wear scar and coefficient of friction are reported using a four-ball wear test machine and a microscope. A rotating upper ball is loaded against three stationary lower balls for one hour, at: 75˚C, 1200 rpm, and 40 kgf load.

Measurement of extreme pressure properties of lubricating grease

The extreme pressure properties, including load wear index, last non-seizure, last seizure and weld load, are reported using a four-ball extreme pressure test machine. A rotating upper ball is loaded against three stationary lower balls for 10 seconds, at 27˚C and 1765 rpm, while the load is increased until the lubricant boundary film is lost and welding occurs.

ASTM B117 Accelerated corrosion test

Salt spray corrosion

The ability of grease to protect steel panels that were sand blasted, coated, and hung over a heated 5% salt solution is quantified by measuring the rust formation over a specified time and film thickness.

ASTM D6184 Oil separation

Oil separation from lubricating grease

The bleeding of oil from grease under static conditions at a set temperature, from 150˚F to 450˚F, for typically 30 hours, through a conical nickel sieve with 1 mm holes, is measured.

ASTM D1264 Water wash out

Determining the water washout characteristics of lubricating greases

The percentage weight loss of approximately 4 g of grease washed out of an enclosed ABEC 6204 test bearing, rotating at 600 rpm for one hour after exposure to 300 ml/min. of water, is reported.

Several professional organisations, such as EPRI and STLE, have identified that 50 – 60% of motor failures are a result of premature bearing failure, due to inadequate lubrication practices. The frequent presence of vibration diminishes bearing life. Alignment, proper footing, and base plates certainly help extend bearing life. However, the service conditions cannot be eliminated completely. Belt driven equipment puts side load on the bearings and ‘flapping’ V belts send vibration directly to the rotating shaft. The American Bearing Manufacturers Association (ABMA) has estimated that a doubling of vibration can reduce bearing life by 75%.1 If these conditions exist, it may be beneficial to select a grease with higher four-ball weld load rating: ASTM D2596. A typical electric motor bearing grease has a four-ball weld load of 160 – 250 kg, while equipment bearing grease may have typical four-ball weld load values of 250 – 500 kg.

Alternative lubricant technologies are available that can provide 250 – 400% higher load resistance and exhibit four-ball weld load of up to 800 kg.

Higher film strength and load resistance reduce the likelihood of spalling. This choice would greatly increase bearing life and result in extended bearing life and extend equipment operational.

ASTM D2596/DIN 51350 Four-ball weld

Table 2. Typical bearing grease performance data comparison Optimised

AL CPC H1

AL CPX H2

Lith Cpx

Consistency, NLGI

#0, #1, #2

#1, #2

#0, #1, #2

#0, #1, #2

Oil separation (ASTM D1742)

0.0 – 0.2%

1 – 5%

1 – 5%

3 – 6%

Heat and speed tolerance

Corrosion resistance (ASTM B117)

1000 hours

50 hours

50 hours

50 hours

pH, H20, galvanic corrosion resistance

Water washout <0.05% resistance (ASTM D1264)

2 – 7%

2 – 10%

5 – 7%

Water resistance

Four-ball weld test (ASTM D) weld point

620 – 800 kg

250 kg

400 kg

500 kg

Shock load and vibration resistance

Four-ball wear test (ASTM D2266) scar diameter

0.38 – 0.4 mm 0.5 mm

0.4 mm

0.5 mm

Bearing wear resistance

42 September 2021 // global mining review

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Applications exposed to water Moisture can devastate bearing life. The polarity of water can easily displace grease as the water has a higher affinity for ferrous surfaces. Furthermore, moisture disrupts the hydrodynamic film due to adiabatic heat vaporising of the water. Lastly, many have firsthand experience of bearing surfaces showing pitting corrosion, black oxide formation on contact surfaces, and red oxide on static surfaces.

SKF indicates that 200 – 500 ppm water ingress can reduce bearing life up to 50%, while levels over 1500 ppm can reduce bearing life by 80%.

Mining applications associated with wet processing such as trommels, wet screens, filter presses, and dewatering presses have bearings constantly exposed to corrosive water and water spray-off. As a result, grease for these applications should have superior water washout resistance and corrosion resistance, in order to mitigate the impact of water ingress by maintaining a protective film on the bearing and passivating the ferrous surface to prevent pitting corrosion.

In this case, the ASTM D1264 Water Washout Resistant Test will be the guide to selecting those greases with the smallest amount of water washout (Figure 1). In this test, a low rating result is considered best. A target might be water washout less than 0.5%.

Unlike typical water resistance tests by EMCOR, the ASTM B117 Accelerated Corrosion by Salt Fog can be used to validate the grease’s ability to prevent corrosion in a wet, exposed condition under harsh corrosive salt conditions. This test is used extensively by the paint and coatings industry to

measure the corrosion resistance on paints, primers, and other coatings. A rating of 50 hours is estimated to equate to three months of real-world exposure, while 1000 hours equates to approximately five years.

In corrosive wet conditions, the choice of a grease with a longer salt fog test duration may certainly help extend bearing life and improve reliability.

Case study: Improving the reliability of mining conveyor bearings Challenge A mining facility wanted to increase reliability and lower maintenance expense of its conveyor belt filters, which included primary and secondary rollers and bearings. The filter press involved 18 bearings and 20 belt support rollers involved another 40 bearings (Figure 2). The bearings were all heavily corroded due to mine water.

The bearing on the left (Figure 1) was re-greased monthly and with a complete change frequency of the bearing unit every four months due to pitting corrosion. During monthly inspection, the grease separated from the bearing components and the initiation of pitting/rust was observed in the housing. The bearings were lubricated with a lithium complex grease with low KPI’s, 5% water washout, and 50 hours Salt Fog. This type of lubricant is not suitable where there is excessive humidity.

The average bearing cost was US$350 each, and the total bearing cost equalled US$60 900/y. The total three-press cost of US$367 000/y included all labour and materials to maintain operation.

Solution The bearing assembly was lubricated with Chesterton 615 HTG 2 – 460. This grease is well suited for large bore bearings in severe conditions. This lubricant has improved four-ball load and wear resistance of 620 kg , a low 1% water washout, and over 1000 hours of Salt Fog corrosion resistance.

Results

Figure 1. Water has displaced the grease from the bearing race and rotating components (left), while grease remains in contact with bearing components (right).

The grease was changed every four months and with a complete frequency of change of the bearing unit every eight months, a 200% increase in bearing life was achieved.

During the five-month inspection, the new grease remained in full contact with the rolling elements of the bearing with no separation or water displacement. The rolling elements of the bearing were also not contaminated with water. There were no indications of pitting corrosion.

Furthermore, the three-press annual cost of operation was reduced to US$198 201/y, a saving of US$168 799/y, and there was a notable increase in up-time of 200%.

Conclusion Selecting the proper grease to use for specific mining equipment and applications is critical to reliability. Learning how to use KPIs can assist in selecting the best grease for mining applications.

Figure 2. Dewatering presses components are exposed to aggressive wet conditions.

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References 1.

American Bearing Manufacturers Association, www.americanbearings.org/

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Geoff Manley, Lubrication Engineering, Australia, explains how lubricant reliability can be improved by using a purpose-built lubrication storage and dispensing system.

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ustralia is a vast land and, while the economy may have once ridden on the sheep’s back, mining and associated minerals processing is now the largest industrial sector in the country.

Mine sites, whether underground or opencast, mining coal or any of the hard rock minerals, are often located in hot, arid regions of Australia and the working

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conditions at these facilities can be extremally harsh for both people and machinery.

As the Australian industry has worked hard to evolve, using the most modern equipment and the latest technologies, the expectation is that mine sites and the variety of equipment at these facilities will operate as required and do the job they are tasked to perform.

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This means that machinery needs to operate for long hours in these challenging climates. Left unmanaged, this creates a significant increase in the likelihood of component failure, should certain, key issues not be addressed correctly.

Effective lubrication Of all of the equipment used in the mining industry, it is the mobile sector that is at most risk of suffering damage, and subsequently loss of production. If a large haul truck or excavator cannot operate, the cost to the

Figure 1. isoPOD® e20 with storage space for intermediate bulk containers (IBCs).

mine site is significant and immediately effects the production output. Reducing and ultimately stopping unplanned failures and outages is a key focus of all mining companies if they want to reduce their operating costs and increase profits.

To counter the risks around premature equipment failures and unplanned outages, it is now readily acknowledged that one of, if not the most important area of maintenance is effective lubrication. Any reduction in the performance of the lubricants being used will have a direct and almost immediate effect on the reliability of the mechanical asset in the field.

There is a wide range of issues that can affect the performance of a lubricant and the equipment it interacts with. Examples of these include cheap oils with: poor base oil quality, incorrect viscosity, poor viscosity index, inability to operate at higher temperatures leading to increased rates of oxidation, incompatibility with equipment including seals and coatings, aeration/foaming, water demulsibility, etc.

While the selection of the most appropriate lubricant for a particular application to manage the above risks is important, managing contamination is equally, if not more, important to the long term, trouble-free operation of the mobile asset.

For too long, lubricants have simply been considered as a commodity and not a critical component of the machine, and because of this they are not given the priority when trying to improve mechanical reliability.

The truth is that every lubricant plays a major role in machinery function and longevity by: reducing friction and wear between moving parts, absorbing shock, reducing operating temperatures, minimising corrosion on metal surfaces, keeping contaminants out of the system, and sealing and protecting components.

Case study In light of the above points, Lubrication Engineering was approached by a major iron ore miner, based in the Pilbara region of Western Australia, to assist with a solution to improve their lubrication practices in relation to their mobile plant. Specifically, they wanted to: Improve the general mechanical reliability of the mobile plant.

Achieve and then maintain compliance with lubricant cleanliness standards.

Improve up-time and overall operational efficiency.

Figure 2. Integrated pumps and filtration above bunded flooring.

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The mobile equipment at the customer’s mine site operates for long hours in a generally harsh environment, so keeping a close eye on the condition of the lubricant in each machine and then proactively responding to any concerns was absolutely critical to meeting production targets. The client stressed that if one system or lubricant was not performing as required, then this could cause the whole machine to fail, which would be extremally costly.

Through a process of consultation, it was determined that an isoPOD® system from Lubrication Engineering

would be a critical component of the broader solution Conclusion to the challenge presented. Lubrication Engineering The implementation of the isoPOD e20 lubricant storage ultimately recommended the e20 isoPOD in this and dispensing system at the customer’s iron ore mine instance because it is a purpose-built lubrication site has significantly improved the overall lubrication storage and dispensing system designed specifically for practices for the routine maintenance processes the external dispensing of lubricants directly into supporting the mobile plant. This has enabled them to critical assets and mobile plant. move forward with more confidence, knowing that they As the e20 unit is readily transportable, it provides a now have a best practice regime in place that will help fast method of implementation that does not require them achieve world-class machinery reliability. significant site works, which reduces establishment Having a well thought out lubrication reliability costs. The unit was delivered to the site and placed in programme is critical to the effective running of a the field, close to the relevant work zone at the mine mobile plant. Lubricants play a major role in machinery site. The ease of installation in the desired location, function, and as such should be considered a critical assisted by the reduced travel time back to the component of the machine. workshop for maintenance top ups on the mobile plant, significantly improved operational efficiency.

Another benefit to the customer’s mine was that the e20 isoPOD could be locked when not in use, meaning the lubricants could be safely and securely stored in a bunded container in the field where they were needed.

One of the most critical aspects of this improvement program was directly related to the site’s strict lubricant cleanliness standards. A key component of the e20 isoPOD design is that each stored lubricant passes through a high quality, high efficiency filter assembly. Knowing the target cleanliness level required by site allowed the filtration package to be specifically designed to meet the cleanliness targets for each oil. Particulate contamination was thus removed from the lubricant before it was pumped into the relevant system on each mobile plant item, ensuring compliance with the oil specification for cleanliness.

A further benefit of the isoPOD e20 unit in this case was that its design and construction provided a way of It’s called: continuous surface mining. Using a machine like the managing, and ultimately Vermeer Terrain Leveler® surface excavation machine (SEM) to perform reducing, the risk of continuous mining allows you to methodically mine or prep a site layer by environmental impact due to layer — optimizing productivity and precision while eliminating many of the safety challenges and restrictions associated with drilling and blasting. spillage, as it is built with an integrated bunding, in Visit vermeer.com/changeyourmine to learn more. compliance with the AS1940 2017 standard.

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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

Caitlin McKinnon, Motion Metrics, Canada, discusses the importance of decarbonising operations in the transition to green technologies.

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he central challenge facing the mining sector today is the necessary transition to decarbonisation. This requires producers to dramatically reduce their greenhouse gas (GHG) emissions, while simultaneously ramping up production of the materials needed to power green technologies. This will be a daunting task for many, but with challenge comes opportunity: while swift and expansive investment is needed to transform

existing energy systems and infrastructure, mining companies that succeed at rapidly decarbonising their operations will be handsomely rewarded in the coming metals and minerals boom.

Reducing GHG emissions To stay on track for the Paris Agreement global 2˚C scenario, all sectors need to reduce GHG emissions from

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2010 levels by at least 50% by 2050 – to limit global warming to 1.5˚C, a reduction of at least 85% is needed.1 However, this is easier said than done, as a low-carbon economy is significantly more material-intensive than traditional fossil fuel-based energy systems, and recycling minerals alone will not meet this demand.2 Solar and wind facilities, for examples, are estimated to require up to 15 times more concrete, 90 times more aluminium, and 50 times more iron, copper, and glass than equivalent fossil fuel-powered facilities.3

Electric vehicles Another example that puts the challenge into perspective is the market for electric vehicles. To achieve the Paris Agreement emissions reductions targets for the transport sector, it is predicted that 120 million electric passenger vehicles need to hit the roads around the globe. In order to make the batteries that will power those electric vehicles, demand for lithium is predicted to rise by more than 1000%. To put these numbers into perspective, the Tesla gigafactory alone will need 25 000 t of lithium – in addition to 17 million t of copper, 7000 t of cobalt, and 126 000 t of graphite.4 The rate of resource extraction worldwide is already three times faster now than it was 50 years ago,5 but, according to a 112-page report released by the World Bank, production of key minerals needs to increase by more than 350% by 2050 to meet demand.6 How will producers elevate production above business-as-usual levels without further adding to GHG emissions? After all, mineral and metal processing and recycling presently contribute more than 15% of global emissions.2 There are no simple answers, but governments and industry are increasingly recognising the need for urgent change and reallocating resources to fund the step change.

including rating indexes like the Dow Jones Sustainability Index and the Carbon Disclosure Project.

A United Nations network of investors called the Principles for Responsible Investment now comprises more than 3000 signatories and represent more than US$100 trillion of assets under management, as of March 2020,7 and major banks are following suit – in 2019, the BMO Financial Group pledged to mobilise US$400 billion in sustainable finance by 2025.8 As Henry Stoch, Risk Advisory and National Sustainable and Climate Change leader at Deloitte Canada, said: “Mining companies should recognise that there is a correlation between stakeholder sentiment and company valuation.”9

Climate change

Governments are also taking their climate commitments more seriously and directing stimulus accordingly. In Canada, large companies that were unable to demonstrate adherence to their obligations under the Taskforce on Climate-related Financial Disclosures (TCFD) were ineligible for federal COVID-19 relief funds.10 The Canadian federal government also announced an updated climate change plan that includes CAN$15 billion in new spending on climate initiatives. One arm of the updated climate plan includes the recapitalisation of the Sustainability Development Technology Canada (SDTC) – an arms-length federal foundation with a mandate to fund new clean technologies – through an investment of more than CAN$750 million over five years.11 Mining companies recognise the tide change and are pledging to join the fight against climate change.

BHP Billiton, Anglo American, and Antofagasta Minerals have all announced plans to power local operations from entirely renewable resources, while Brazilian mining giant, Vale, has committed to achieving 100% self-production from renewable resources by 2025 in ESG metrics Brazil, and by 2030 globally. De Beers has also pledged It is estimated that a quarter of all professionally to reach carbon neutrality by 2030.12 managed assets are now scrutinised based on These plans are ambitious and necessary, but environmental, social, and governance (ESG) metrics, switching to renewable energy will take time – at present, only 2.5% of the mining sector’s electricity comes from renewables.10 In the meantime, researchers estimate that half of the most cost-effective approaches to mitigating climate change up to 2030 will be realised through the implementation of energy efficiency technologies.2 With the stakes this high, and given that 70% of digital transformations initiatives fail to achieve their stated goals, mining companies should choose their technology vendors very carefully as they compete in the new green economy. 13 Motion Metrics believes that value-aligned, subscription-based Figure 1. By monitoring mine shovels, loaders, haul truck paths and conveyor partnerships, where both buyers and belts, the Motion Metrics ecosystem transforms image data into actionable suppliers have a stake in success, best insights.

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promote the conditions for successful innovation. Like its customers, the company is a student of the sustainability movement – but having been at the intersection of mining and technology for nearly two decades, the company understands the challenges that large adopters face when navigating a rapidly changing landscape and dizzying array of innovation opportunities. It partners with opencast mines to measurably improve production and energy efficiency, while keeping employees safe. To accomplish these outcomes, it uses artificial intelligence (AI)-enabled, military-grade cameras to radically optimise operations without interrupting the workflow.

With the Motion Metrics technology ecosystem, mines can start fighting climate change today, while saving up to US$30 million/y. By monitoring mine shovels, loaders, haul truck paths and conveyor belts, the ecosystem enables particle size measurements throughout the operation, truck and belt volume monitoring, ground engaging tools monitoring, and boulder detection.

Motion Metrics then turns this data into actionable insights by tapping into highly skilled and experienced domain experts. The service has a payback period of weeks by delivering the following productivity and efficiency improvements: + 6%: Analyse particle size to optimise each stage of comminution. + 6%: Monitor and optimise haul truck payload with volume sensing. + 1.5%: Mitigate equipment downtime caused by broken GET components. + 1.2%: Minimise haul truck carry-back with monitoring. + 1%: Keep oversized material out of the primary crusher with boulder detection.

130 000 t of carbon dioxide equivalent and 2.6 million m3 of freshwater savings each year. 14

Conclusion As the effects of climate change become more visible, major mining companies are acting to decarbonise existing energy systems and infrastructure. And while minerals production must increase to meet the growing demand for a green economy, technology provides a safe and sustainable path forward. Switching to renewables will take time, but existing energy efficiency technologies, such as those on offer from Motion Metrics, can help producers to begin the transition today.

References 1.

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4.

5.

6.

7.

Although these benefits are significant, Motion Metrics is just getting started. In September 2020, Motion Metrics secured a CAN$5.6 million investment from the federal government to lead a collaborative energy efficiency project titled: ‘A machine vision- and AI-based solution for optimal comminution in mineral processing circuits’.

With help from its consortium partners KAZ Minerals, Optimize Group, the University of British Columbia (UBC) Mining Department and Steinert USA, the company will extend the value of its proven particle size analysis technology through development of specialised ore sensing techniques to remove waste rock from the processing stream and further increase energy efficiency.

Comminution, the process of progressively reducing the size of mined material, presently consumes approximately 4% of electrical energy worldwide and approximately 50% of overall power consumption at an average mine site. With this funding, Motion Metrics will develop a commercial mine-to-mill solution that will reduce energy consumption during the comminution process by at least 15%. For a medium-sized copper mine, this energy saving translates to approximately

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8.

9.

10.

11.

12.

13.

14.

MASSON-DELMOTTE, V., P., et al.,‘Summary for Policymakers’ in Global Warming of 1.5˚C. An IPCC Special Report on the impacts of global warming of 1.5˚C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable developments, and efforts to eradicate poverty, https://www.ipcc.ch/ sr15/chapter/spm/ HODGKINSON, J. H., and SMITH, M. H., ‘Climate change and sustainability as drivers for the next mining and metals boom: The need for climate-smart mining and recycling’, Resources Policy, (2018) VIDAL, O., GOFFÉ, B., and ARNDT, N., ‘Metals for a low-carbon society', Nature Geoscience, Vol.6, No.11, (2013), pp. 894 – 896.

HOMLES, F., ‘Copper prices could turn red hot thanks to alternative energy’, Business Insider, (30 June 2015), https://www.businessinsider.com/copper-prices-will-increase-due-togreen-energy-2015-6?IR=T ‘Resource extraction responsible for half world's carbon emissions’, The Guardian, (12 March 2019), https://www.theguardian.com/ environment/2019/mar/12/resource-extraction-carbon-emissionsbiodiversity-loss ‘Mineral Production to Soar as Demand for Clean Energy Increases’, World Bank, (2020), https://www.worldbank.org/en/news/pressrelease/2020/05/11/mineral-production-to-soar-as-demand-for-cleanenergy-increases CLARK-LOWES, R., ‘UN PRI: Everything You Need to Know’, Orbis Advisory, (2021), https://www.orbisadvisory.com/news-list/ un-pri-everything-you-need-to-know ‘BMO Financial Group to Source 100 Per Cent of Electricity Usage From Renewables’, BMO Capital Markets, (2020), https://capitalmarkets.bmo.com/en/news-insights/news-releases/ sustainable-finance/bmo-financial-group-source-100-cent-electricityusage-renewables/ O’BRIEN, J., and STOCH, H., 'Trend 3: ESG: Getting serious about decarbonization’, Deloitte Insights, (2021), https://www2.deloitte.com/ xe/en/insights/industry/mining-and-metals/tracking-the-trends/2021/ decarbonization-mining-and-climate-change.html ‘Climate Change Requirements a Feature of new COVID-19 Federal Loan Program’, McCarthy Tétrault, (2020), https://www.mccarthy. ca/en/insights/blogs/canadian-era-perspectives/climate-changerequirements-feature-new-covid-19-federal-loan-program Environment and Climate Change Canada, ‘A Healthy Environment and a Healthy Economy’, Government of Canada, (2021), https://www. canada.ca/en/environment-climate-change/news/2020/12/a-healthyenvironment-and-a-healthy-economy.html ‘De Beers plans to clean up diamond supply chain, be carbon neutral by 2030’, Reuters, (2020), https://www.reuters.com/article/us-de-beerssustainability-anglo-amercn-idINKBN28A2QX ‘Flipping the Odds of Digital Transformation Success’, BCG Global, (2020), https://www.bcg.com/publications/2020/increasing-odds-ofsuccess-in-digital-transformation ‘Motion Metrics Joins the Fight Against Climate Change with Funding from Sustainable Development Technology Canada’, Motion Metrics, (2020), https://www.motionmetrics.com/motion-metrics-joinsthe-fight-against-climate-change-with-funding-from-sustainabledevelopment-technology-canada/

Dr Niels Leemput, ENGIE Impact, Australia, outlines the four main strategies that mines can implement in order to set and attain achievable carbon goals.

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he mining sector is under a lot of pressure from multiple driving forces to decarbonise and reduce emissions. As more organisations publicly announce sustainability efforts, there is a growing interest from investors, employees, and customers to reach carbon targets quickly and gain a competitive advantage. There are also operational risks to consider, with increasing energy intensity at mining sites, and of course the potential impacts of more extreme and more frequent climate events. Even mining longevity can be a concern – in an industry that is often thought of as ‘outdated’, it can be challenging to recruit top talent, which will be critical in order for these organisations to transform and innovate. The lower mining organisations prioritise sustainability transformation and decarbonisation efforts, the less resilient they will be to all these risks.

However, there are unique challenges to decarbonising an emission-heavy industry such as the mining sector, and duality on the stakeholder side has prevented companies within this

sector from achieving net zero, as economical carbonisation solutions are limited. As a result, miners want to implement green initiatives within the industry, but struggle to unlock sustainability at an exceptional price point.

There has been progress within the sector – many organisations have already begun actively working with clients to find low-carbon alternatives. As mining organisations look to make strides towards reducing carbon footprints, here are four main strategies that could be implemented to help mines set and attain achievable carbon goals.

Build an achievable and flexible net-zero roadmap The main challenge when establishing a path to net-zero is developing a roadmap that aligns with the company’s unique situation and sustainability goals. There is no one-size-fits-all approach to net-zero – there are often infinite paths to reaching carbon targets, and certain paths are more complex than others.

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The level of complexity when building a roadmap is determined by long-term goals. For example, does the company hope to be ‘true green’, with no interaction with fossil fuels? Once the long-term targets are identified, organisations can map out the different paths and strategies that can be taken to reach carbon neutrality. It is key to conduct scenario analysis across a wide range of potential pathways, in order to identify the specific pathways that are the best fit for the mining company’s specific circumstances.

A good example of this approach is the zero-carbon roadmap ENGIE Impact developed for OZ Mineral’s new copper-nickel mining development at West Musgrave, Australia. The roadmap contains a set of pathways that factor in where ENGIE Impact thinks technologies will be in the future. The pathways come with a set of decision gates throughout time, at which the company needs to choose if they are to pursue that particular decarbonisation pathway.

In building a roadmap, it is important to ensure that all stakeholders are part of the process, in order to ensure alignment in priorities and resources. There are varying stakeholders with competing priorities to consider and address.

With larger companies, for example, there are typically more resources and budget, but there is often a lot of shareholder pressure to maximise the return on investment. For smaller companies, there is less capital, but these companies can afford to be nimbler and pivot strategies quickly. In addition to internal stakeholders, there are external stakeholders as well. For instance, regulatory agencies set strict levels of Scope 1, 2, and 3 emissions that mines must strictly adhere to. It is important to have participation and buy-in from all stakeholders when

Figure 1. Current vehicles that use diesel fuel should be replaced with electric or fuel cell hydrogen mining trucks.

building the roadmap, in order to ensure alignment from the beginning. This will help to prevent roadblocks in the future and streamline decision-making.

Finally, a successful roadmap must allow for flexibility. The path to net zero is not a straight line, and because it can take years, if not decades to achieve, there will inevitably be new challenges, as well as opportunities, to consider. Therefore, the roadmap should be a continuous process, reassessed yearly, and tracked with key performance indicators (KPIs) to account for changes within the sector. It is critical to work with a range of assumptions, high and low, when setting goals and building a roadmap, which helps to leave room to adjust for various external factors, such as: new and emerging technologies, new regulatory requirements, or shifts in market demand for the goods being supplied.

A successful roadmap drives operational efficiency, bolsters productivity and captures new value streams for the organisation, all while reducing emissions and working toward a zero-carbon future.

Identify short term goals and quick-win opportunities Short-term wins should be baked into the decarbonisation roadmap. With a holistic view of the organisation, leadership can identify which mines have the most opportunity for decarbonisation in the short-term and take action to make progress immediately. From there, mines can continue to identify ways to reduce emissions that will have a high impact at a low cost, with quick implementation.

As mining companies typically have a global portfolio, a good first step is to identify where the mine is grid connected. From there, operators can look for ways to start incorporating green power, through leveraging available green power purchase agreements (PPAs) for a part of the electricity demand.

Renewable energy is a scalable technology, so mining companies have the benefit of starting small with a hybrid approach and working their way up. Once the availability of renewable energy sources is determined, mines can strategise a safe and economical way to increase their use of renewables over an acceptable amount over time. By starting small, the mine can test reliability and can then scale up.

Mines located off-grid can begin reducing emissions by integrating a limited amount of renewable energy, such as solar PV, to lower field bills without overhauling the entire energy infrastructure. Over time, the amount of renewable energy can be increased, including the addition of energy storage for required supply-demand matching.

Even small steps towards sustainability have a significant impact, particularly when looking at the industry as a whole.

Consider if all mines adopted 20 – 30% renewable energy: the global impact would be astronomical compared to one company committing to 100% renewable energy, solidifying the importance of starting at the top to examine the entire portfolio.

Identify and invest in technology

Figure 2. Digital tools are increasingly supporting the mining workforce.

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There is a lot of innovation happening in the sustainability space, and mining companies are in a prime position to take advantage of these emerging technologies to support carbon-zero initiatives. For instance, consider electric vehicles (EVs): by replacing current vehicles that use diesel fuel with

electric-powered mining trucks, mines can take a big step in reducing their emissions. In 2019, Anglo American developed a hydrogen-powered mine haul truck, which will help reduce its footprint significantly.1 However, the lack of market availability of hydrogen-powered solutions is still a barrier to entry for many organisations.

Another emerging technology is battery storage. Identifying a sustainable replacement for batteries is an important part of the technology mix as well, especially for off-grid mines looking to leverage more renewable energy sources. Most batteries are designed to be used for a few hours, but if mines need year-round green energy, long-term energy storage at scale is critical. Currently, the only mature technology used for long-duration storage at large scale is pumped hydro storage.

For mining sites with substantial elevation differences and space to build water reservoirs, this can be an effective solution.

Technology is going to play a major role in the decarbonisation of the mining sector, and it is not a secret that it will be expensive to develop and implement new green solutions. It is worth noting that the influence of larger mines can create collective pressure to make technology more affordable and accessible. The mining industry has an enabling role to play in bringing the cost of technology down by creating demand, and bigger players have more power to trigger a ‘snowball effect’ to drive price premiums down for green products.

Measuring and tracking progress with targeted KPIs To keep an organisation accountable and on-track with regards to its zero-carbon roadmap, measuring and reporting progress is key. The specific metrics and KPIs that mines should track may differ depending on the targets, the type and number of mines, location, and so on. Some typical metrics include the energy or carbon intensity of different products – if there is an increasing growth in activity, it is necessary to decrease carbon intensity to put the mine on a trajectory toward net zero. Another common metric is the total share of renewable energy and decarbonisation in the overall mix.

Other examples of economic KPIs that can be tracked to help prove the effectiveness of the investment in reducing carbon emissions include the cost of carbon abatement, and the levelised cost contribution of the sustainable solutions.

Comparing these KPIs for the opportunities identified allows mines to rank and prioritise them, starting with the most cost-effective ones first.

There is an overarching responsibility on the part of the entire executive team to set, monitor and report on sustainability

goals, and sometimes these efforts are even reflected in executive compensation. Without cross-functional participation, it becomes too easy for sustainability to become a secondary priority.

Case study: Vale New Caledonia In a decarbonised future, the world still needs raw materials like steel, lithium, and nickel to create the products that will enable a transition to zero-carbon. Vale New Caledonia produces nickel predominantly intended for the battery industry, and has recognised the need to produce an end-to-end carbon free product. When committing to sustainable development, studying a zero-carbon solution was the most logical first step to drive both Vale New Caledonia’s mission to care for the environment, and to also further establish competitive strength in the Asia Pacific region.

As a first step in developing its sustainable future, Vale New Caledonia partnered with ENGIE Impact to conduct a concept study to provide insight into the different pathways to carbon neutrality.2 The purpose behind this was to identify the mine’s zero-carbon objective, weighing the possible trade-offs between energy and carbon savings, capital and operational expenditures, and return on investment. After determining a clear strategy and roadmap, Vale New Caledonia identified a trajectory to transition to a zero-carbon nickel and cobalt mining operation within less than two decades, even considering the expected increase in energy consumption.

Conclusion Mining companies serve every industry within the economy.

Even in a decarbonised future, humans will need minerals and materials to reach zero-carbon. Often, a downstream process needs to be taken into consideration to achieve this, as the mining sector itself can be considered a Scope 3 industry. By encouraging the identification of renewable sources within the industry, and leveraging new emerging technologies, mines can begin exploring long-term energy options to achieve sustainability goals.

References 1.

2.

‘ENGIE and Anglo American to co-develop renewable hydrogen solution to decarbonize the mining industry’, ENGIE, (2019), https://www.engie. com/en/journalists/press-releases/anglo-american-develop-renewablehydrogen-solution-decarbonize-mining-industry ‘ENGIE Impact Provides Strategic And Actionable Support For Vale New Caledonia To Reach Its Zero Carbon Target And Boost Competitiveness’, ENGIE Impact, (2020), https://www.engieimpact.com/news-and-events/ vale-new-caledonia-zero-carbon

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Michèle Brülhart, The Copper Mark, Switzerland, examines the important role copper is playing in the global transition to a green economy, as well as some ways copper production itself can become greener still.

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n its May 2021 report on ‘The Role of Critical Minerals in Clean Energy Transitions’, the International Energy Agency (IEA) reaffirmed the vital role which critical minerals will play in supporting the transition to a decarbonised, green global economy by providing the essential materials for the development and use of the major clean energy technologies.1 Copper, in particular, is a critical material for almost all clean energy technologies, including: solar photovoltaics (PV), wind, bioenergy, electricity networks, electric vehicles (EVs), and battery storage (Figure 1). Driven by the growing investment in green and carbon zero technologies, the demand for copper continues to rise and is such that it cannot be met through recycled copper alone, meaning that it is not a guarantee of lower emissions overall. It means that promoting decarbonisation in the copper industry, even as production of copper increases, will require innovation on the part of actors across the supply chain.

It is essential that innovation and adaption within the copper industry does not focus exclusively on efforts to decarbonise. The industry is challenged to consider broader environmental and social issues, including: water usage, pollution from tailings, and the impact of the copper production on local communities. The future legitimacy of the industry will depend on the ability of actors in the copper supply chain to do no harm and to positively contribute to sustainable development in the local communities and economies within which they operate, by adopting

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responsible production practices. As part of this, The Copper Mark is working with companies and organisations throughout the copper industry, in order to enable them to better understand and meet the increasing demands for independently verified, responsible production practices.

Decarbonising the copper supply chain Before exploring some of the broader themes in terms of responsible copper production, it is important to emphasise that copper demand is expected to increase by up to 50% in the next 20 years alone, and could rise tenfold by 2050 if states remain committed to achieving a low-carbon energy future.2 While the copper industry has a fundamental role to play in accelerating the green transition, it also presents challenges in terms of ensuring that the copper supply chain does not disproportionately increase its own carbon emissions.

There are a number of important and encouraging examples of companies throughout the copper supply chain innovating to address these concerns – reducing their carbon footprint while maintaining and expanding productivity. This includes a number of companies with sites that participate in the Copper Mark: at its Copper Mark-assured Kennecott Utah Copper operations – including its flagship Bingham Canyon copper mine that supplies 15% of the US’ copper demands – Rio Tinto has entirely phased out the use of coal to power its mining, recycling and crushing operations, and now instead uses solar and wind power. This has reduced Kennecott’s carbon emissions by 65%, equivalent to approximately 1 million tpy of carbon dioxide (CO2).3 Elsewhere, Antofagasta has introduced a series of initiatives that has allowed it to achieve a 580 000 t emissions cut between 2018 and 2020.4 This was followed by an announcement from the Chief Executive this year, committing the organisation to net zero emissions by 2050.5 Furthermore, in a world first, this May Aurubis’ smelting and refining operations developed the first copper anodes

Figure 1. Critical mineral needs for clean energy technologies.1

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produced with hydrogen, introducing another low-carbon energy source into the copper production chain.

There have also been positive trends around the increased recycling of copper – another important means through which the copper industry can address the challenge of decarbonisation, as copper recycling can require significantly less energy than mining.6 Approximately 50% of the copper used in Europe now comes from recycling, and globally copper recycling now saves up to 40 million tpy of CO2.7,8 Despite this progress, recycling processes are not carbon neutral either, re-emphasising the importance of innovation at the mining, smelting, refining and fabricator levels of the supply chain, in order to promote zero-carbon methods of copper production and manufacturing.

Broader social and environmental considerations While promoting decarbonisation should remain an important focus for actors in the copper supply chain, it must also be understood in the context of broader social and environmental challenges, which the rising demand for copper will only make more pronounced. A rapid transition to a net-zero global economy – driven by the increased extraction of minerals and metals – has the potential to magnify social and environmental challenges which already exist.9 One of the most significant negative outcomes effected by the increased demand and extraction of copper, particularly from ores of lower grade, is the growth in copper waste – often in the form of copper tailings.

As highlighted in the OECD’s 2019 report, copper waste and tailings can lead to serious contamination of land and water, severely impacting local communities.10 Growing concern around the pollution caused by copper tailings has led to positive examples of innovation within the industry with a view to mitigating the negative social and environmental impacts. In 2020, for example, the Global Industry Standard on Tailings Management was launched in response to the Brumadinho tailings dam disaster.11 The standard was developed under the leadership of The International Council on Mining and Metals (ICMM), the United Nations Environment Programme (UNEP), and the Principles for Responsible Investment (PRI). It underlines the need for a more collective approach to tailings management, in order to help prevent catastrophic failure and enhance the safety of mine tailings facilities across the globe.

This kind of action is an important step in the right direction, but more must be done by companies at the asset level – both to reduce harm to people, and to minimise the

environmental impact in the communities within which copper operations illustrate the importance of promoting they operate. responsible production practices, which go beyond the Water usage is another factor which must be taken into imperatives of decarbonisation. Within this, there is an account when assessing the impact which the growing important role to be played by downstream copper users, demand for copper has on surrounding communities and particularly in terms of conducting the necessary due the environment. Water is used in the copper industry for a diligence and engaging closely with their suppliers, in variety of purposes, including: direct and indirect cooling, order to ensure that the copper they use has been waste transport, flotation, slag granulation, and responsibly produced. The copper industry as a whole has electrolysis. In Chile, the largest copper producing country a vital role to play in working to prevent, mitigate and in the world, recent forecasting suggests that the remedy negative environmental and social externalities, industry’s consumption of continental fresh water could and to positively contribute to sustainable development in reach 14.53 m3/sec. in 2029, equivalent to an increase of the local communities and economies within which it 12% on consumption in 2018.12 As this freshwater usage operates, through responsible production practices. rises, so too does the risk of extreme water shortages and References knock-on negative impacts for the rights of local A comprehensive list of this article's references can be found communities, as well as on agricultural productivity. In on the Global Mining Review website: 2019, Chilean water usage for mineral mining, combined www.globalminingreview.com/special-reports/ with an 80% drop in rainfall, left the country facing its worst drought in a generation.13 Going forward, it is vital to ensure there is access to water for water rightsholders and that they are supported in YOUR MINING MACHINE DESERVES THE BEST CHAINS implementing the latest Cincinnati Mine Machinery Company designed and installed the first Dual Sprocket water conservation Conveyor Chain. Our unique design utilizes superior metals and a proprietary heat technologies and treatment process for unparalleled strength. Our Dual Sprocket Conveyor Chain practices. runs longer and stronger which means less downtime and lower cost per ton. So There have been when it's time to choose, choose the strongest chain under the earth. For over 90 positive improvements in y e a r s , C i n c i n n a t i M i n e M a c h i n e r y c o n t i n u e s t o b e T H E S T R O N G E S T L INK. this direction. At the Escondida mine – which participates in The Copper Mark’s Assurance Framework – BHP and Rio Tinto have jointly invested US$3.43 billion into developing a desalination plant to reduce their reliance on freshwater, and BHP has pledged to stop using fresh water drawn from the surface and underground in Chile by 2030.14 While these are positive developments, the use of continental fresh water in Chilean operations continues to rise in absolute terms, highlighting the need for greater action to reduce freshwater usage.

Conclusion Both the concerns around tailings pollution and rising water usage for Contact us at 1•513•728•4040 or visit cinmine.com to learn more about Cincinnati Mine Machinery products.

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Xavier Iraçabal, Saft, France, explores the growing advantages of battery electric power for underground mining vehicles and summarises key strategic choices in their charge management.

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n addition to improving workplace health and safety with their emission-free operation, battery electric vehicles (BEVs) have the potential to control costs for mining companies. In order to maximise their economic and practical benefits, owners must choose the right combination of charging approach and battery chemistry for their specific application.

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Diesel or battery?

Diesel-powered load, haul, and dump (LHD) machines – and other underground vehicles used for the transport of people, equipment, and materials – emit noxious gases and harmful particulate pollution. They also generate extra heat. The cost of ventilation and cooling to deal with these problems increases almost exponentially as mines become deeper.

Ventilation alone is estimated to account for approximately 40% of the energy used by a typical underground mine, and then there is the cost of installing and maintaining the required infrastructure.

BEVs, producing zero emissions and easily meeting increasingly stringent environmental regulations, are a much healthier option. As well as protecting air quality, they generate less noise, vibration and heat, creating healthier and productive working conditions.

With lower pollution levels in the mine, ventilation systems can be downsized – saving on both capital and operational expenditure. If the electricity needed for battery charging is supplied from renewable sources, such as solar and wind, the reduction in carbon dioxide and cost-saving effects of BEVs are even greater.

BEVs are inherently more energy efficient than diesel vehicles, and use sophisticated electronic control systems that optimise the delivery of power and torque. In simulations, the energy cost per tonne of material handled has been shown to be three times

higher for diesel than for battery electric machinery. BEVs also save considerably on maintenance costs, as they have fewer moving parts.

Continuing developments in lithium-ion (Li-ion) battery technology have extended BEV advantages over diesel machines. Ideally suited for underground mine work, Li-ion batteries can provide high levels of performance, energy density, safety, longevity and temperature tolerance (-25˚C – 55˚C).

Battery swapping or fast charging?

An underground mining vehicle normally carries out a five-year tour of duty, after which it is repaired, refurbished, or scrapped.

Its batteries must have the durability and robustness to perform with total reliability over that period, despite heavy use in harsh and often hot environments. They must also cope with extreme charge and discharge cycles, supporting 24-hour vehicle operation.

The need for frequent charging of BEV batteries was once seen as a limitation to their use in underground mines, but modern Li-ion technology has overcome this. In particular, it has brought about faster and more flexible charging. Users can choose between two charging strategies: battery swapping or fast charging.

Battery swapping requires two batteries per vehicle. While one is powering it, the other is being charged in the swap-and-charge station. A heavily worked battery may need charging after approximately four hours or more. It is then swapped for a freshly charged one. The swap typically takes approximately 15 minutes, and can be timed to coincide with a planned work break.

With this approach, the battery can be charged relatively slowly, putting less pressure on the mine’s existing electrical infrastructure. However, the downside is the need for lifting equipment, space, and labour to handle the swapping safely.

The alternative is to use a fast-charging battery, which stays onboard the vehicle and is rapidly charged during shift breaks.

As an example, Saft batteries can be fast-charged in approximately 15 minutes. With conveniently placed electrical points, drivers can also top up the charge level by ‘opportunity charging’ during even shorter breaks. Unlike traditional lead-acid technology, Li-ion gives flexibility for this type of partial and opportunity charging, regardless of the existing Figure 1. Battery systems need to match the typical five-year life state of charge, without adversely affecting the battery. of underground mining vehicles The specialised equipment and higher currents needed for fast Table 1. Comparison of charging regime outcomes in real-life scenarios charging may require investment in Battery swapping Fast charging (single battery) upgrading the mine’s electrical Typical LHD shift 4 – 6 hours operation 2 – 3 hours operation infrastructure. This demand increases (+15 minutes swap time) if large numbers of vehicles are to be Charging time 3 hours (battery off vehicle) 15 minutes (battery of vehicle, with charged simultaneously. ultra-fast charge) Both approaches have their place in the mining industry, and the best Expected calendar life 3 – 5 years 5 – 7 years choice will depend on applications and Expected cycle life 2500 cycles 20 000 cycles circumstances. To give some idea of how their differences play out in real Table 2. Comparison of charging regime outcomes in real-life scenarios life, Table 1 compares outcomes in two Chemistry Energy density Cycle life Calendar life Fast charge Safety scenarios. Each is based on an LHD NMC/Graphite +++ ++ ++ ++ + weighing 45 t laden and 60 t fully LFP/Graphite ++ ++ ++ ++ ++ loaded, with a load capacity of 6 – 8 m3 NMC/LTO + +++ ++ +++ +++ of material.

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Charging-related downtime is lower in the case of battery swapping – at 15 minutes/6 hours of operation, as opposed to 15 minutes/3 hours. Either way, the swap or fast charge can be timed to take place when the vehicle would already have been idle anyway. More noticeably, the fast-charging scenario delivers a longer battery lifespan and cycle life.

NMC, LFP, or LTO? Like traditional batteries, Li-ion cells store and release energy via electrochemical processes. A crucial difference with Li-ion is that those processes are controlled by an inbuilt electronic battery management system (BMS).

This monitors cell voltage and temperature, manages charge and discharge for optimum performance, protects the battery, extends its life, and safely shuts it down if a short circuit or thermal runaway is detected. It also monitors state of charge (SOC), indicating how long the vehicle can run before recharging, and state of health (SOH), indicating the battery’s remaining lifespan.

A wide choice of Li-ion chemistries exists. These can be used singly or blended to give the ideal combination of properties for a specific application. Key factors include: Energy density: how much energy the battery can hold in proportion to its weight or volume.

Cycle life: the number of charging and recharging cycles possible within its useful life.

Calendar life: the number of years it will last.

Fast-charging capability.

Figure 2. Choice of Li-ion technology gives OEMs flexibility to meet specific requirements for mine operators

Safety.

Most commonly, the Li-ion cell’s positive electrode (cathode) will be made from lithium nickel-manganese-cobalt oxide (NMC), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

The negative electrode (anode) is usually graphite or some other form of carbon.

NMC and LFP are currently the most popular choices for underground BEVs, especially with battery-swapping regimes.

Both offer long runtime and can charge in less than one hour.

LFP has a lower energy density, so the battery needs to be larger to achieve the same voltage and energy. However, its materials are less susceptible to price fluctuation and it requires fewer additional safeguards.

LTO batteries are a more recent development, combining an NMC cathode with an lithium titanate oxide (LTO) anode. These can be fully charged in just 15 minutes and deliver a very long cycle life – three to five times that of other Li-ion batteries – even under extreme charge and discharge cycles.

Ideal for fast-charging regimes, they also score well on safety and reduce the need for costly preventative measures. While their lower energy density means they take up more space on the vehicle, there is no need to mount them in an accessible position as they are charged on board.

Table 2 compares the three main electrochemistry choices with regards to five key factors.

Future flexibility?

To meet changing needs and variation in requirements between different vehicles and applications, Saft favours a modular and easily implemented approach to battery design, manufacture, and supply. Its plug-and-play systems are based on standardised 48 V building blocks, which can be readily assembled and adapted to each situation.

This echoes the strategy of vehicle manufacturers, who prefer to use a single electrical system as the framework for equipping a variety of BEVs. In doing so, they shorten the development and testing time for each model, bringing new products to market more quickly and cutting costs.

Saft’s battery system modules offer LFP, NMC and LTO options, incorporating Li-ion cells and all the necessary monitoring functionality. Each will meet high performance needs and can be tailored for specific applications by adding extras such as heavy-duty metal enclosures and thermal management or fire suppression systems.

Conclusion

Figure 3. Today’s Li-ion technology has the right performance and reliability for underground mining.

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Zero-emission BEVs for underground mining vehicles are gaining in popularity, thanks largely to their health, environmental, and cost-saving benefits. High productivity can be maintained through battery swapping or fast charging, with an appropriate choice of batteries from the various Li-ion chemistries now available.

Once the mine operator has decided on its preferred mode of charging, it is up to vehicle OEMs to specify the battery to deliver the required properties and capabilities. Through extended choice, modularity and specialist advice, battery companies can provide both mine businesses and vehicle manufacturers with the flexibility they need to meet all of their needs.

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Christian Fimpler and Frank Kathmann, Eaton, explain how recent technological advances are making communicating underground more efficient and effective.

onnectivity and the human-machine interfacing are concepts being embraced across many industries – and with good reason. The ability to share information, analyse data and respond in real time to fault signals or maintenance requirements, is key to optimising production and driving down costs. Indeed, in industries such as mining and tunnelling, the ability to co-ordinate humans and machines, as well as relay essential data about what is happening in real time back to the surface, is not only a matter of optimising production, it can be life-critical.

Designing a hazardous area communication system While there is no doubt that communications between the surface and those below ground, between both machines and humans, are essential functions, there are a number of challenges to overcome when designing a hazardous area communication system.

Firstly, there are the natural environmental risks associated with working underground. Damp, dust, and potentially explosive atmospheres are not conducive to the introduction of sophisticated electronic communications networks.

Secondly, the nature of drilling, mining, and tunnelling operations add other environmental phenomena that can be detrimental, such as high levels of vibration and noise. It is therefore important to ensure that essential messages can be relayed without interference, and that they cannot be ‘missed’ by the intended recipient.

A third consideration is the nature of industry. The underground working environment is highly mechanised, and

the scale of the equipment involved is colossal. For example, vertical shaft drilling machines – commonly used for sinking sewers, mine, and ventilation shafts – have a typical diameter of between 4.5 – 9 m. These machines generate a lot of heat and vibration in very confined spaces. Communications devices therefore need to cope with wide variations in temperature and high levels of electronic interference.

Now the environmental conditions have been summarised, the human element needs to be considered.

Although far fewer people work below ground now than in previous decades, they are subject to new safety challenges.

Proximity to large scale and remotely-controlled machinery is one risk, but also, with fewer personnel underground, workers are now working at more remote distances from both each other and help, should it be needed. It is not unusual for mines and tunnels to stretch for hundreds of kilometres underground, and people are still required to penetrate these vast, manmade caverns to service and repair equipment. The need for reliable and timely communication is growing, rather than diminishing, as operations become more automated than ever.

Current communications The complexities of communicating underground have led to a number of solutions being developed over time. For example, communications systems using public address and voice alarm (PA/VA) technology have evolved to relay voice messages and audible warnings; automation systems exist to enable control and co-ordination of machinery and equipment; and fixed point telephones provide emergency call points for personnel.

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Initially, these systems were reliant on analogue technology and hard wiring, limiting the amount of data that could be transferred. However, the fundamental issue with current-state underground communications systems is lack of integration. Each type of communications system has evolved to be separate and distinct from the next, so the benefits of true connectivity are still largely unattainable, despite the advent of digital technology.

Some manufacturers, including Eaton, have sought to close this gap. The MR90 radio system, for example, was introduced in the early years of the 21st century. It serves double duty as a voice transmitter from mining conveyors to the fixed station and back, as well as transmitting data between the fixed station and conveyor station, using omni-directional antennae.

Using the same hardware for communications and production data is progress of sorts, but it still lacks the ability for seamless connectivity between machines and between humans and machines. Nor does it exhibit the agility and flexibility that is possible using the latest technological advances – including mobile phones and tablets – which other industrial sectors already enjoy.

Step change All this is set to change with the advent of the safety integrated mining automation system – or SIMAS. Developed by Eaton, drawing on its expertise in hazardous area communications, SIMAS is believed to be the world’s first fully integrated IP-based voice, data, WiFi, interlock, and automation system for subsurface industrial applications where rugged and/or explosion proof equipment is required.

The system uses Ethernet to link the automation system components via a SMART connection. This network structure and a high data transfer rate of 100 Mbit means SIMAS meets all requirements for automation processes of equipment, such as: plow and shearer faces, conveyor systems, pump stations, etc.

The automation control unit channels all process-specific automation processes and acts as a communication point to the control station. It also allows a data link to third-party systems.

The system is equipped with an integrated, safety-oriented PLC with flatscreen display, function keyboard and button-entry mouse, which enables implementation of a control concept in line with IEC 61508.

A system control panel – complete with command/message components, LCD colour backlit display, emergency stop button with interlock, and speaker with audio functions – enables manual control of operating and conveyor equipment.

A range of Ex i I/O modules and periphery modules complete the automation functionality.

The emergency stop element of SIMAS comprises a control unit and a choice of emergency stop buttons, rope-pull switches, and coupling devices. The control unit is used as a driver for up to two emergency stop lines. It displays operating and diagnostic data from the system, as well as an overview of the devices connected to the emergency stop lines. The control unit is connected to all devices on the network using a specially developed system line, which routes the emergency stop circuit, the power supply, and the network communication. A factory-set ID allows identification throughout the SIMAS system.

SIMAS WiFi communication options include fixed point radio transmitters (with or without intercom), access points, and emergency rope pull switches with integral intercom and access point. Mobile options include mobile phones and tablets in IS housings.

The overall SIMAS system is designed for ignition protection group ATEX group I M2. In addition, the emergency stop and shutdown facilities use battery backup to meet ATEX group I M1 in the event of a main power supply failure. In combination with a failsafe PLC, SIMAS also meets the requirements of functional safety in line with SIL2.

Potential applications for SIMAS include coal faces, belt conveyor transportation systems, water management and machinery automation, as well as communication along underground roads. Due to its scalability, SIMAS could also be used for shaft signaling, skip loading, or wagon loading.

Future developments A proprietary application, ‘SIMAS Connect’, is currently under development. It will enable voice connections and video conferences between mobile terminals, fixed stations, and computer workstations. Address book functions will allow both private connections and global communications, while authorisations for the mobile devices can be set on the communications server.

In the near future, Eaton also expects to add addressable fire evacuation and the ability to track personnel constantly – with the ability to send tailored, personal messages to further improve efficiency and safety.

Conclusion

Figure 1. In mining and tunnelling, the ability to co-ordinate humans and machines, as well as relay essential data in real time back to the surface, is not just about production efficiency, it can be life-critical.

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Due to the hazardous nature of mining and tunnelling operations, the sector is understandably cautious about the adoption of new technology. Nonetheless, in the case of a fully integrated communications and automation system, such as SIMAS, it is likely that the significant benefits, in terms of personnel safety and process integration, will overcome any conservatism.

This step-change in connectivity for hazardous underground applications will deliver major improvements in error reduction, maintenance scheduling and uptime, as well as ensuring that personnel receive timely and accurate data at the point it is required.

Ceren Şatırlar Balcı, Barkom Group Drilling Rigs and Equipment, Turkey, outlines the importance of the feasibility stage and field investigations of the drilling sector to mining geoscience.

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rilling has become a technique that requires constant improvements, following the increase of raw material needed as a result of the industrial revolution. Deep and shallow drilling has been implemented in petroleum, groundwater exploration, geotechnical investigations and the mining industry, in particular, since the second half of the 19th century. Every drill rig manufacturer should play its role in a drilling industry that is actually a primary supplier to every single industry in the whole world.

In this article, feasibility stage and field investigations of the drilling sector are discussed as one of the most important segments of engineering and mining geoscience.

Preliminary stage of field examinations and feasibility investigations are often fulfilled with heuristic engineering approaches.

There are several parameters and variables that affect the performance and the efficiency of drilling operations.

These include: The experience of the driller.

The technical specifications and durability of the drill rig.

The quality of the drilling equipment used, and its suitability to the ground conditions.

The use of the right drilling additives with the right mixtures.

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When drilling takes place in challenging formations, for example where there is a risk of collapse, it constitutes great operational risk and might conclude with the loss of a complete borehole and equipment. When evaluating the drilling performance at the preliminary examination stage,

it is of great importance to decide on the right rig and equipment to be used for the drilling, in terms of engineering approaches and determining the profitability of the drilling process.

Preparing for the future

Figure 1. Maximum high performance and efficiency is provided with the strong four-speed transmission integrated gear box with 9500 Nm torque.

Figure 2. A secondary rod holder system during break out can achieve more thrills with the help of special jaws performance, enabling easy performance and fast rod running out.

Figure 3. High safety and easy operation is offered by a pilot monitor control panel.

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Barkom Group closely follows the latest developments in this rapidly changing world, in-line with its vision. The company puts great effort into employing elements such as innovation, sustainability and cooperation, by implementing new generations of products and processes.

Based on these factors, it then develops its own technologies to achieve more success in the world.

The company’s research and development (R&D) centre, which is approved by competent government bodies, helps contribute to future solutions by developing reliable products and technologies. Within this context, the company collates its drill rig product range under three main categories, which are: underground, surface, and exproof Atex certified drill rigs.

Each drill rig is named according to its specific drilling capacities and different functions.

Barkom's latest rig models is the BULLDRILL® BD1200S surface drilling rig, produced as a result of long and detailed research and design surveys by the company’s R&D team.

The rig was made ready for use using the data verified by tests with the following features after the design verification phase.

The BD1200S diamond core drill rig meets demanding surface drilling applications. It is designed for shallow and deep hole core drilling, with the functionality to drill rotary for shallow casing. Developed using the latest technologies, it is the most flexible and efficient drilling rig in its series. It is capable of drilling over 1200 m in depth with NWL, and is equipped with a powerful slide system with which to handle deep drilling. In order to increase its mobility, a compact chassis has been designed by choosing robust crawlers with high carrying capacity. The drill rig has many standard features – such as a second rod holder (adapted to the upper part of the chuck jaw), rod supporting system, and remote control mobility – which are often optional on other equivalent rigs. The rotating head, which becomes much stronger with the four-speed gearbox integrated into the drilling unit, has been given the ability to drill with the highest efficiency, in all conditions, anywhere. All drilling and motion functions can be performed with Rexroth, Parker, or Kawasaki brand powerful hydro motors and pumps, driven by a 300 hp Cummins or Volvo brand diesel engine with proven reliability and efficiency.

The powerful rotation unit delivers high-levels of torque for greater productivity, and features a simple, open design for ease of maintenance and accessibility. Drillers also benefit from the increased flexibility and mobility provided by the long feed stroke. When changing from 3 m drill rods to 6 m drill rods, almost no effort is required because of the additional telescopic piston.

The BD1200S surface drill rig delivers a high-level of efficiency, thanks to its rigid pole structure, that can be used with a 6 m core barrel, and its telescopically extendable mast. The ergonomic mast, which closes during transportation and provides ease of loading,

Figure 4. Opened using hydraulics and closed with gas springs, the rod holder system has a rod holding capability of 18.5 t. The jaw system has the feature of holding up to P dia. (114 mm).

When the jaws are removed, the inner diameter can be expanded up to 210 mm.

Figure 5. Rod support units, in particularly, ensure that the rods are placed at the same line with the drilling unit and centred when working with a rod of 6 m. It also has a support system to fix the threads during pull up.

creates practical transportation and working opportunity.

The poles of the construction that make up the mast are durable; their capacity is more than enough to carry the whole weight of the drill string, and there is a BRADEN brand winch with a carrying capacity of 18 t. The gas-filled rod holder system, which is also strong enough to verify the winch capacity, offers a robust deep well drilling solution.

Control and warning system indicators, that facilitate the monitoring of all drilling equipment and functions, are located on the control panel. In addition, a multifunctional screen (murphy), showing diesel engine functions and engine malfunctions, is located on the control/operator panel.

BD1200S includes mast handling and assembly characteristics. All drilling operations are centrally controlled from the control panel, located at the rear of the rig. The drill rig is easy to operate and maintain, featuring an open design for clear access when servicing.

High safety and easy production is offered with a pilot monitor control panel. On the panel, there is a red lion speed indication and burkert mud pump flow indicator.

With the multifuctional screen, the monitoring of data – such as the diesel engine’s excursion level, oil pressure, engine revolution, and battery voltage value – can be easily monitored from the digital murphy panel. Rod running in and rod running out processes are more practical with joystick use.

It can be adjusted, drilling functions can be followed from the desired point with the moving control panel, and the operator height can be moved to the desired level. The control panel has the capability to rotate axially, while moving up and down with special pistons.

The next steps The next model from Barkom Group is due to be a multi-functional drill rig capable of performing both diamond core drilling and reverse circulation (RC) drilling.

Diamond core drilling and RC drilling are drilling techniques that contain completely different systems. Multi-functional drill rigs allow two methods to be conducted with one single drill rig.

For the BD1200S and the future multi-purpose drill rig, the company worked and is working closely with Drillex International, which has 30 years of knowledge and experience in the sector.

Conclusion

Figure 6. The BD1200S offers efficient results even at high depths in diamond core drilling with B, N, H and P sizes.

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As technology develops day by day in the field of mining and drilling, Barkom Group Drilling Rigs and Equipment recommends to always look for more in less, as it is all in the drilling. Considering that developing technology will bring different engineering solutions with it, the suitability of a certain drill rig for the field and drilling depends on its efficiency, quality, and multi-functional capability – the crucial factors to success. Each improved piece of equipment, and the development of new systems on the drill rig, will increase productivity by affecting the expected drilling performance, as it will provide: safety, durability, mobility, low maintenance requirements, adaptability, a reduced labour requirement, and faster operations.

Daniil Victorian, Doofor Inc., Finland, addresses how smart investment plans and the implementation of LEAN principles can help mining companies acquire the right mining equipment for them.

Q

uarrying is comparatively a simple process; however, it is open to several issues pertaining to logistics, technology, sustainability, and financial performance.

Financial performance The latter is on the mind of every investor, owner, shareholder, and stakeholder that associates themselves with the mining industry. Cost-efficiency is the key ingredient which drives the decision-making process for many

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end-users worldwide. When it comes to acquiring new mining technology, feasibility of use and operator comfort is often discarded, in order to preserve a greater return on investment (ROI). Purchasing mining machinery is a long-term investment, in which capital and operating costs are both taken into consideration. Capital expenditure typically includes machinery costs, as well as the cost of transport and deterioration (residual value). Operating expenditure is comprised of fuel costs, maintenance costs,

and operator costs. What often happens is an attempt to reduce initial capital expenditures in the hope of low operational costs, but this is rarely the case. By saving money in the short-term, companies are inadvertently accepting an economic pitfall, or ‘stepping into monetary quicksand’.

There is a reason why newer technologies cost more than their older counterparts.

Although buying the newest, most advanced technology on the market is guaranteed to reap positive results, it is first crucially important to determine exactly what is required. By taking into consideration the size of the quarry and scope of machinery, operators set themselves up to make the right choice and achieve optimum performance.

This process is comparable to a well-known car manufacturer with LEAN practices rooted at the core of their production. By operating at optimum capacity and utilising just the right amount of resources, the best possible results can be achieved.

Business suitability The next step is business suitability. After determining what type of machinery is required, it is important to consider the following elements: Spare parts availability.

Mechanical suitability of equipment.

After sales service.

If the stars align, i.e., the right product has been chosen from a suitable supplier, a sound financial decision has been made.

To facilitate this choice, WORD Rock Drills have developed an easy-to-use hydraulic quarry drill system that offers maximum productivity and cost-efficiency. The ‘RAPTOR’ has

been designed with the operator’s comfort in mind and is quickly becoming the drilling solution of choice for many end-users across the US, as well as other countries.

The marginal income of a quarrying business is relatively small, therefore it is vital that the acquired equipment has good ROI potential and is financially sustainable in the long-term. The size of the quarry and the scope of machinery are economically interdependent. WORD Rock Drill’s RAPTOR is a universal solution for quarries of all sizes. In terms of payback, the RAPTOR offers significant savings.

In addition to being economically efficient, the RAPTOR provides a comfortable, temperature-controlled cabin for the operator; removes over 35% more airborne dust with a powerful dust collector system; allows the operator to set up drilling parameters from inside the cab; and operates as a self-contained, mobile unit, which does not require any external power source.

Operational expenditure A big chunk of operational expenditure for mining machinery comes from labour costs. Machinery that involves a complex control system will be more labour intensive to run and, in turn, will require personnel with unique skill sets that are difficult to come by. With a system that is user friendly and easy-to-operate, one does not have to worry about the challenges faced from having limited knowledge or expertise. With features such as the ‘SMART shield’ – which detects drill bit and rod breakages, loss in air pressure and blow-outs of the stone – human error can be dramatically reduced.

The SMART shield contains a variety of intelligent sensors, wired by CAN bus technology, to ensure effective communication between electrical components, such as: relays, sensors, and encoders. In combination with a camera

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alignment system, which utilises a 20˚ surface level, the operator can drill safely and uninterruptedly, without ever needing to leave the comfort of the cab.

Another key feature of the RAPTOR is flexibility. With a quick coupler system, the front loader attachment can be changed as

Figure 1. Front loader attachment with SMART shield and Doofor DF530X rock drill.

Figure 2. A side view of the RAPTOR with dust collector system visible.

and when needed. All RAPTORs are equipped with 7/8 in. x 4 ¼ in. steel tapered drills and have 118 in. vertical and 110 in. horizontal hammer travel. Drill hole spacing is programmable to the stone type with three, quick-pick options on the remote: 4 in., 6 in., and 12 in. One can also cycle between different depth configurations, depending on the type of stone being drilled, offering the option to make on-the-go adjustments.

The high-performance dust collection system is another unique selling point of the product. The dust collector system consists of four major components: vacuum, air compressor, rock box with trap door, and a hydraulic fluid reservoir. The reasons why it is so special are two-fold: All pins and bushings utilise high-quality PTFE bearings, which eliminate the need to use grease, along with hydraulic hose assemblies designed to meet ISO 4406 cleanliness standards. Eliminating the need for grease significantly reduces incidents of stone dust sticking to wear surfaces, resulting in longer component life. Additionally, the operator does not need to spend time greasing the pins, making it, once again, a cost-efficient and time-efficient solution.

The on-board compressor is a ‘VMAC Predatair’, which is lightweight, compact, and capable of delivering 100% duty cycle. The use of advanced, digital technology allows for reduced fuel consumption and heat generation with the use of ‘stand-by mode’. When there is no demand for air, the compressor will enter ‘rest mode’ and wake immediately when air is required. An LCD control unit allows operators to monitor compressor oil temperature, air pressure and system hours, making it possible for on the spot analysis to be conducted. Over-temp safety sensors protect against extreme weather conditions and ensure that hydraulic oil is at safe operating temperatures.

The drilling is performed using highly durable and efficient Doofor DF530X hydraulic rock drills. The DF530X rock drill is designed to maintain optimal percussion pressure at high penetration speed. It is suitable for demanding dimensional stone and quarrying projects, as well as general excavations.

Inside the rock drill, a patented trapezoid piston shape enables the piston to generate higher frequency rates and minimise frictions between steel parts. The results of this are good drill tool life and an overall smoother drilling process.

Doofor’s DF530X continues the RAPTOR’s dedication to flexibility by having a compact and modular design, providing the user with plenty of customisation options and ‘problem free’ maintenance. This rock drill can be equipped with a variety of rotation motors – i.e. 8 cc, 12.5 cc, 20 cc, 32 cc, 40 cc, and 50 cc.

This, in turn, gives the user more control over the desired rotation speed and torque.

Conclusion

Figure 3. Operator view inside the RAPTOR cabin.

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Currently, many mining businesses are seeing a spike in turnover and profitability, due to a rise in fiscal stimulus programmes adopted by governments to support local economies in response to the COVID-19 pandemic. Such businesses should be encouraged to make smart investment plans and implement LEAN principles into their purchasing behaviour. Choosing the right supplier and the right product can be an arduous task, but, once done, it will save time and money in the long run.

Eloise McMinn Mitchell, Pix4D, Switzerland, asks the question: what is the point of using a drone?

T

he mining industry has always faced huge challenges as it tries to meet the constant demand for its resources.

Streamlined and optimised workflows are critical to keeping material moving from one place to the next, saving money and time. However, in order to stay safe, mining sites need constant monitoring and care. Revolutionary new tools and practices, when proven to work, become hugely influential in the industry. Drones and unmanned aerial vehicles (UAVs) are already doing this. This article explains how, and why.

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Introducing drones Firstly, what is the point in using a drone? Drones are manoeuvrable, adaptable pieces of technology, and as a result of this adaptability, they can be used in all forms of mining, from opencast to placer, or even underground mines. For example, there are specific drones built to move around in enclosed spaces. These are equipped with protective cages so their rotors are not damaged as they fly.

The value of using drones in mining is fairly obvious: they see more. Drones can cover large areas of a site, capturing images faster and in more depth than people on the ground.

They can provide a video feed of a site, showing live movement across the mine, but the true value comes in their photos. A typical 4K video can be captured with most standard drones today, but the still images extracted from a

video only have a resolution of approximately eight megapixels. Alternatively, most cameras fixed to a UAV nowadays are capable of producing a photo of 20 megapixels and more. That scale-up in resolution provides far more detail and information. There are cases where a video is better than imagery, and some data collection plans rely on video, but this can create a trade-off in terms of image quality, although whether this affects a project depends on the outputs that are desired.

Drone imagery What good are photos of a mine? There is a huge range of applications for drone imagery.

Surveying the site An obvious use for drones is mapping, and using them to capture topographical data. Many drones can now use RTK or PPK technology to provide incredibly precise geolocation data alongside their imagery, which can be used to confirm measurements and calculations of a mine. This can be used to generate a 3D map and/or point cloud with the right photogrammetry software. Other outputs include a Digital Surface Map and Digital Terrain Map. All the information about the site’s dimensions, volume of stockpiles, etc., is available in that model.

Improving site safety and asset management Figure 1. A drone inspection of a mine is quick and effective.

The information gathered with drones can be used to assess current safety standards – e.g. to measure the width of a track across the site to check for subsidence, or aerially inspect machinery for faults. Assets can be checked for damage or rusting, where specialised software can automatically detect rusting as well as allow inspectors a detailed view of a potential fault.

Measuring details of a mine Whether it is the volume of a stockpile, the distance travelled by employees while carrying equipment, or the depth of an opencast mine, drone imagery can provide these details faster than manual measurements.

Streamlining operations Figure 2. Open quarry sites can easily be 3D modelled with photogrammetry software.

Whether it is taking inventory of equipment, or just saving the time spent tracking changes to the site, drones help speed up all of these processes with minimal effort, providing a cost-effective alternative to repetitive, manual labour.

Long-term records Maintaining records of historical drone data makes it possible to observe how a mine has changed over time, including measures taken for environmental protection, refilling of opencasts, and any upgrades that may have been made.

Figure 3. Measuring stockpiles with a drone is a straightforward process.

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These applications culminate in drones being used worldwide by mining companies for site surveying, blast engineering, stockpile inventory and volume calculations, asset management, topography engineering, and environmental monitoring and regeneration.

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There are, of course, some potential challenges in working with UAV technology. Firstly, there can be hanging obstacles on a site, such as power lines, that a drone pilot should avoid crashing into. Magnetic interference from large quantities of specific materials can be problematic for hardware, including some drones, as it can disrupt components. Finally, the shifting landscape of a mine means that records taken with a drone need to be kept up to date, although automated flight plans can mitigate the effort required in this.

One of the typical outputs from photogrammetry is the orthomosaic, which is a 2D flat map built from the images that can be exported as a GeoTIFF. Orthomosaics are used to give an overview of site information and are often used in presentations for decision-making. Additionally, photogrammetry software generates a point cloud (a collection of points where each one has specific coordinates), a raster surface model (to quantify and visualise terrain), Digital Surface Models and Digital Terrain Models, contour maps, and even thermal maps if needed. These outputs can be consolidated with Interpreting drone imagery laser scanning or LiDAR data as well, which can be imported The photos captured by a drone include crucial geolocation into CAD software for further logistical planning. data, as well as the physical image of the site. This can all be Working with drones can be incorporated into existing imported to specialised photogrammetry software that workflows, as the drones can fly overhead quickly and measures from images. This software then uses that efficiently around a site, minimising (if not negating) the information to create actionable, useful outputs for mining need to turn off or move equipment out of the way, and teams and corporations. saves inspectors long walks around the space.

The software provided by Pix4D is not hardware specific, so surveyors can use hardware of their choosing, the majority of which is supported by Pix4D software.

Pix4D has five products that are specifically useful for the mining industry, including: PIX4Dmapper, a comprehensive photogrammetry software capable of a large range of outputs, including thermal imaging; PIX4Dmatic, specialised for large scale and corridor mapping, and thus well-suited for large mining sites; PIX4Dsurvey, which incorporates Figure 4. PIX4Dmapper enables users to look at individual images, as well as the 3D model. photogrammetry outputs with LiDAR to bridge the gap between photogrammetry and CAD, allowing outputs to be vectorised and merged; PIX4Dcloud, an online photogrammetry platform, which makes it easy to share results, inspections, and outputs with teams wherever they are in the world; and PIX4Dcatch, a terrestrial photogrammetry application which uses the latest phones and tablets’ incorporation of LiDAR and ToF sensors to gather ground-level data from mobile devices, which can later be processed in PIX4Dmapper, PIX4Dmatic, or PIX4Dcloud to generate precise 3D models.

Figure 5. Drone imagery is effective underground, although specialised drones are best for this.

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Software such as this offers three key features that benefit mining companies, besides the obvious ‘bigger picture’ and 3D mapping capabilities: Reduces operational risk: The software removes the need for visits and site inspections without losing track of everything. Fewer people required on site keeps people safe and prevents disruptions to workflows.

Supply chain management: The software can track where the material is on-site, where it needs to be, and can spot delays or issues early on.

Asset lifecycle management: Equipment can be inspected from the comfort of a computer screen, working with technology that will help automatically identify faults and measure features.

Results of using drone mapping A precise, accurate 3D map of a site is incredibly valuable, especially for a mine where large objects are being moved around and uninformed decisions can have a big impact on a job site. Project managers can share their findings with colleagues and make the right decisions with the most up-to-date and accurate information. They can equally share identified hazards or issues with their superiors and corporations more easily, exporting pdf reports as well as imagery. This information can then be used to solve problems, as well as plan future expansions and measure or assess the current state of a mine.

Volume measurements are a critical element in mining.

Shifting large volumes of earth or materials is a huge undertaking, and can pose a safety risk if not done correctly.

This being the case, risks can be easily mitigated if everyone is informed and site changes are carefully tracked, which is simple to do with regularly updated site surveys. Routine updates mean that everyone can follow site movement and progress, as well as identify logistical challenges early on, saving money and time later down the line.

Drone mapping in action Case study: Montana, USA The narrow passageways of an underground mine were once an insurmountable barrier to drone mapping, as the small paths were too difficult to navigate without the drone crashing.

Barrick Gold, working on Golden Sunlight Mine in Montana, USA, took advantage of a modern drone that solved that problem. The ELIOS 2 is a UAV designed for enclosed spaces, surrounded by a small frame that prevents it from bumping into walls and getting damaged. It also has a mounted lighting system, so that it can gather illuminated images in the darkness of underground mines.

In order to survey for unstable material that could be a threat to people and equipment, Barrick Gold sent a drone into the mine to check that recently blasted areas were safe for miners to enter and pass through. The company repeated the flight several times over a week and processed their data with PIX4Dmapper. The 3D models were then compared to each other to identify material that had moved and flag risks.

The outputs of this were two-fold. Firstly, the team had a model of the mine to use for checking if the mucker was at risk of damage from a rockfall, as well the current status of recently blasted material. Secondly, the mine owners had a perfect replica of the mine that could be used for company records, including planning and tracking expansions across the site, even underground.

Case study: Aberthaw, Wales Before being decommissioned in March 2020, the coal plant at Aberthaw in Wales was a huge site that needed to be inspected and well maintained. PricewaterhouseCoopers (PwC) was brought in to audit stock at Aberthaw, in order to help keep track of resources and material being moved on the site.

The company flew its drone for just over 30 minutes, gathering over 300 images. These were collected with a fixed-wing drone from QuestUAV. Fixed-wing drones have a longer flight time and can be paired with a base station to ensure absolute geolocational accuracy. Rotary drones, in contrast, can have more manoeuvrable flight plans and a direct ascent take-off.

Originally, manual measurements taken on the site would take over four hours, which disrupted work and machinery. The drone took just 30 minutes – an 85% reduction in inspection time. The 3D model generated by PIX4Dmapper with the collected data was used to measure volumes of the stockpile with results having an overall accuracy of 99%. The software also provided a digital twin of the site, which can be used to plan how the stockpile will be moved or added to.

A report filed by PwC following this trial projected that using drones to boost productivity in the UK in similar cases could save around £16 billion (US$20 billion) by 2030.

Conclusion

Figure 6. Monitoring site access, such as roads, is another use for drones in mining.

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Drones themselves are a useful tool, but it is how they are used in combination with photogrammetry that is the game-changer for the mining industry. Drones save time, improve safety and cut down on wasted money, whilst the application of photogrammetry introduces new, valuable resources like accurate maps and on-demand inspections to the industry. With the right photogrammetry tools, there is almost unlimited potential for what can drones can achieve at a mine.

Emily Loosli, Wingtra, Switzerland, identifies how drone mine surveys are setting a new pace for the industry, using a Canadian coal mine as an example.

L

ocated in Southeastern Saskatchewan, Canada, between the city of Estevan and the town of Bienfait, is the Estevan Mine site, which is operated by Westmoreland Mining, LLC. The site spans 20 331 ha.

(50 240 acres) and the mine comprises four active pits supplying lignite coal to the two power generating stations in Saskatchewan – the Boundary Dam Generating Station and the Shand Generating Station – as well as the activated carbon plant and char plant. It also supplies some domestic sales. The mine’s production is approximately 6 million tpy.

Like all mine sites, Estevan presents a range of challenges, including measuring volumes accurately and generating views of the mining pits and work progress on

a regular basis. In addition, there are also increasingly detailed safety regulations that mine sites must adhere to. In order to stay competitive and ensure that working conditions remained as safe as possible, Westmoreland did what it has always done to keep business thriving over the last 150 years: it changed with the times.

Mining’s next frontier: drones and high-accuracy data By now, it is no secret that commercial drones have the power to transform how work is done across industries, including mining. Specifically, a drone can fly over a pit and collect visual data that is both clear and geo-referenced for 3D accuracies, facilitating the

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creation of digital twins of the area. Additionally, because it is much faster than covering the area on foot, it can be done more frequently.

Seeing all the ways that drones improve operations, Westmoreland started incorporating drone technology into its workflows in 2014. A co-op engineering student at Westmoreland, working with the WingtraOne drone on the Estevan Mine pits, said that compared to other data collection techniques, drones are the most accurate way to get data on a mine site, by far. How so?

The accuracy of stockpile overall mine pit measurements depends on the data points collected along the site’s surface. Depending on the quality of the sensor on the drone, this can be as much as a data point every square centimetre or so. Data like this greatly reduces the difference between the actual volumes and surfaces and those measured by the drone data.

The WingtraOne drone, in particular, can capture at sub-centimetre ground sample distance (GSD), which means centimetre-level accuracy across the entire mine site.

In the past, surveyors used GPS equipment as they walked around the mine pits. To an extent this worked, however, due to safety concerns, they could not effectively survey the side slopes. In the places where they could reach, they collected several hundred

Figure 1. Drone pilots fly WingtraOne approximately three times a week to gather vital details around the mining pits at Estevan mining complex.

Figure 2. The WingtraOne drone helps track operations at Estevan mine, which occur on a massive scale and quickly.

‘Big Lo’ is a Bucyrus-Erie 2570-W dragline vehicle at the complex and is considered a wonder of the region for its science-fiction-grade size and ability to haul 230 t in one suspended load.

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data points. Now, in 15 minutes, a drone can pick up millions of data points across an area that used to take two hours to cover on foot.

This level of accuracy saves time by offering a new level of precision with regards to how much earth or residual is in a given place, at a given time. When working with this much detail, mining operations become more and more predictable and trackable.

Furthermore, when high-accuracy drone data is the basis for discussions, potential confusion among stakeholders about stockpile volumes are also minimised, thanks to software that allows team access to datasets in real time.

Mine managers can rest assured about safety as well, because surveyors no longer need to walk amidst moving industrial equipment or climb up onto stockpiles. In fact, drone technology removes most of the major worksite safety risks in an opencast mine.

Choosing the right drone Westmoreland has been incorporating drone technology into operations across its mining sites for the last seven years. In that time, what drones can do has changed, so the mining firm has added to its fleet accordingly. At first, multi-rotors, like the DJI Phantom, were the dominant means of collecting data. These drones instantly became a much better option than covering the same grounds on foot. However, a multi-rotor’s limited flight time and coverage range per battery presented challenges that became obvious when fixed-wing commercial drone technology started to develop.

Fixed-wings broke through a coverage barrier, allowing data capture over areas many times larger than multi-rotors, due to the aerodynamics of their design.

Specifically, fixed-wing drones, like commercial aeroplanes, rely on passive lift to stay in flight, so they consume less power and stay airborne longer. Yet, for mine sites, these have presented one key challenge: how they land.

Classical fixed-wing drones must either be launched by hand or catapult, and will belly land. On a rugged mine site, this introduces a lot of risk that the drone and its sensor will be damaged. In fact, the landing of the fixed-wing drones the mine had been using could be described as a ‘crash landing’. This risked not only causing damage to the drone and data, but also collision with nearby equipment or operators, since the drone would land in unexpected places.

For all of the above reasons, when Wingtra came out with its vertical take-off and landing (VTOL) drone, WingtraOne, it presented a step forward in large-area mapping drone technology and attracted the attention of Westmoreland.

VTOL: the optimal solution for drone mining surveys On rocky work sites that present limited take-off and landing areas, VTOL drones offer the best of both worlds: direct lift-off from the home position, large-area data

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collection, and a controlled touch-down landing that both protects the equipment and ensures minimal safety risks.

These features are already a big step forward for mines. Yet VTOL goes further, as it enables the use of higher quality sensors that would not be viable with either a fixed-wing (due to the hard landings) or a multi-rotor (due to the constant lift it requires to fly).

What difference do high-quality sensors make? First, they offer higher resolution, so more data per image.

Next, as is the case with WingtraOne, they can carry heavier, full-frame cameras, so the capture area is even larger. This means that the drone can fly higher, fit larger areas into every shot, and cover much more

ground in a single flight, at a higher accuracy, and with better resolution.

All of this not only speeds up the survey process, but it also avails an entirely new way to manage mining operations. For example, instead of waiting for a semi-annual mine site survey, site managers can request a map of a pit or some stockpiles on-demand, and then often receive the data within the same day, depending on the size of the survey.

Through minimising disruption of operations with a safe, fast drone survey, site managers can get more frequent looks at their operations and fine-tune schedules accordingly. For example, WingtraOne can map an area that used to take up to five hours on foot in 30 minutes, at a significantly higher accuracy.

How much training and knowledge transfer is required to go high-tech?

Figure 3. A WingtraOne stockpile image from an Estevan Mine pit. This output, based on rich data, is used to generate contours and calculate the volume of the stockpile.

Figure 4. A WingtraOne data output of an Estevan Mine pit.

This is used to see if the draglines are working to design and to calculate how much dirt has been moved since the last flight.

It is also used to design ramps down to the pits as part of a plan for reclamation of the dirt that has been moved. Most importantly, it is used to see if there are any conditions within the pit that could be dangerous or cause burial of coal (such as high wall failures).

All of the benefits of drone technology are powerful to consider, but if using the technology presents hassle and setbacks, the return on investment is significantly reduced.

In fact, the ease-of-use and compatibility of the data with other software and pre-existing workflows is vitally important to how much a drone proves to be an asset for a large mining firm with large teams of workers and demanding timelines. In an increasingly competitive marketplace, more and more reliant on new technology, the level of ease and efficiency is not just convenient. It is actually the key to staying ahead.

Additionally, drone data needs to be compatible with a range of software so that the latest data processing and sharing technology is also available to stakeholders. In fact, some mining software can generate specific measurements such as safety berm heights, crests and toes, road boundaries, widths, crests, slope, length, and elevation change. Then artificial intelligence can highlight where a site falls out of sync with safety standards or presents hazards.

Westmoreland’s latest choice in drone technology – emphasising ease-of-use and software compatibility – reflects its consistent spirit of innovation and keeping up with the times in order to stay well on top of safety regulations and calculate dragline operations, as well as the amount of reclamation they have done to meet sustainability goals. In the end, adopting the most advanced commercial drone technology sets a good example for the mining industry, with the added potential for significant cost savings.

Conclusion

Figure 5. This WingtraOne drone data output offers rich data on an area of Estevan Mine that Westmoreland plans to reclaim.

The output is used to design a reclaim surface that is sent to the dozer operators, in order to accurately restore the area to design.

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As more mining companies incorporate drone technology into their workflows, a new precedent is quietly being set based on faster, higher-accuracy data collection. Different drones present different advantages, and the technology is developing swiftly. Taking the time to research and learn what is available today will improve the likelihood that the technology will fit into and improve current workflows, as well as contribute to achieving business goals over the long term.

Rebecca Long Pyper, Dome Technology, USA, outlines how domes beat flat storage in longevity, strength, and capacity.

D

urability; innovative foundation systems; more storage in a smaller footprint; and simpler product loading and unloading. These benefits have been enticing coal, copper, limestone, molybdenum, potash, bentonite, and other mining companies to choose dome storage for decades. And with systems increasing in sophistication all the time, companies who select a dome invest in longevity too.

Two bulk-storage options dominate the mining industry today: domes and flat storage (warehouses). When choosing a storage facility, companies should consider necessary capacity, site conditions, stored-product requirements, and features built into the two options.

Space requirements and storage ability The first Dome Technology domes were hemispherical – they required a large footprint, and their diameter was greater than their height. This model is still the go-to option for mining storage, best where capacity is king and land is inexpensive.

Domes store a large volume in a smaller footprint, stacking product deeper and taking up less property at a site. While some customers require three to five warehouses to store product, a single dome will likely accommodate the same amount of material. The double curvature of a dome lends itself to the ability to build up,

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rather than out, and the curve provides strength at all points of the structure. Because domes are monolithic structures, any forces interacting with the dome are distributed evenly throughout the shell, rather than being concentrated to weak areas like corners or joints.

This gives the dome a longer life cycle than a

steel structure. Also, the dome’s ability to sustain large loads at the apex means ample support for head houses, fill conveyors, and dust-collection systems.

Flat storage in general requires a larger footprint since product is usually stacked a maximum of 20 – 30 m deep.

Customers can expect a warehouse to utilise 100 – 150% more area than a dome holding a similar amount of product. Each dome is also planned with the stored product in mind, and thus maximised for optimal capacity and product protection.

Case study: Climax Molybdenum

Figure 1. In a dome, product can be stacked deeper than in flat storage. The hemispherical dome like this is still the most popular dome model for mining products.

Figure 2. The Climax Molybdenum dome was designed to interface with existing infrastructure and was built in just four months.

Climax Molybdenum needed ample storage at its Leadville, Colorado, mine, but there was a catch: in order to make this project economically feasible, the new structure had to utilise an existing conveyor system and be robust enough to hold the weight of the conveyor, headhouse, and expected snowfall.

After seriously considering another type of dome, a monolithic concrete dome from Dome Technology was selected. A dome capable of storing 130 000 t was built to accommodate the existing conveyor system, which was reassembled to feed directly into the apex.

Cost-savings, then, were two-fold: the customer reused an existing conveyor system, and additional costly support systems were not required to share the load. The dome’s strength provided another advantage.

With its location in a snowy clime, the structure was engineered to surpass a snow load of 5.27 kN/m2 (110 PSF), while supporting the apex mechanical load. A different type of free-span, column-free storage facility could not support a similar load on its own.

The project came with other challenges too. At an elevation above 3353 m (11 000 ft), weather conditions suitable for building would last just four months of the year. Since a dome’s rapid construction process is ideal for quick construction, project managers and crews maximised workdays to expedite construction and complete the job within the amount of workable time.

Dust control was another concern, but the dome’s seamless storage capabilities easily contained the product, reducing dust throughout the site and the minimising the environmental impact.

Foundations

Figure 3. ADM chose a dome for its site in Clinton, Iowa, based on better product protection.

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Flat storage is often built using concrete walls topped with a wood or steel structure. Because flat storage is constructed using different materials, any differential settlement will cause the ‘pieces’ to separate. A deep foundation is often necessary unless the structure is built on firm ground.

As dome engineers have become savvier, foundation options have increased. A dome’s strength and geometry provide a tolerance for differential settlement – an important consideration for heavy materials.

Geotechnical engineering and site analysis ensure proper foundation performance. In contrast to a flat storage, the dome is continuously supported by the ring foundation, as a result some differential settlement does not adversely affect the structure, where some

differential settlement in a flat storage is generally not acceptable.

In a dome, sometimes a ringbeam is the only necessary foundation system, and customers can save millions when a dome’s deep foundation is reduced or eliminated. However, when more stability is required, companies have options: For sites with preferable or acceptable soil conditions, a ringbeam provides a shallow foundation alternative. Where applicable, the frost depth will determine the ringbeam’s depth, but usually the ringbeam is inserted 2 – 4 ft into the ground.

For sites where the top 6 – 8 ft of ground is of less-than-ideal material, crews excavate the material, replacing it with controlled structural fill. This model allows for some settlement, but the amount will be within tolerable parameters for a dome.

When the top 15 – 50 ft of soil is questionable, stone columns are often an option. First, crews use an auger to remove earth from a hole with a 30 in. dia. until a more stable, soil-bearing layer is reached.

Rock then fills the hole and is compacted, increasing the stiffness of the soil below the dome.

When deeper foundations are required, other systems are available.

seamless construction protects the coal even during inclement weather events. A dome’s capacity is also advantageous in supplying a way to achieve desired throughput from a single storage structure, rather than requiring multiple silos.

Dome Technology competed for the project against a company providing aluminium or steel domes. In the end, ADM chose a steel-reinforced concrete dome from Dome Technology, as the company could offer a viable solution that was significantly less expensive than the alternative.

ADM liked the dome option because it did not have any beams or trusses for dust to collect on. Not only does this ensure safer operations within the dome, but it will help ADM to be a better neighbour to nearby communities. Domes effectively contain dust and help businesses meet local regulations, while subsequently fostering good relationships with local communities.

The dome was fixed with a circular stacker reclaimer that provides even filling for coal. The advantage with a stacker reclaimer like this is the ability to inventory stored product by age. This helps companies control their inventory and where they stack and reclaim product from the pile.

The project’s success led to Dome Technology securing another ADM project in Columbus, Nebraska, for a dome of similar size storing the same type of coal.

Product protection

Design-build services

Higher-maintenance products like coal require special attention. Dust-management systems are always an option with domes, and the truss-free interior means no surfaces for dust to accumulate on. When a coal facility is planned, engineers discuss the best approach for explosion venting.

Design-build services address engineering, construction, and all related systems at the design level. The result is greater simplicity, assurance, and value from start to finish. When a single party is chosen to provide the entire project, costs go down. When the plan changes, it is not taxing to spread the word because everyone who needs to know already does.

However, sometimes changes are not necessary at all.

When one team oversees every element, it is easier to spot gaps. The result is a turnkey facility with components more likely to run seamlessly because each was planned with the others in mind. Turnkey construction is about more than combining individual parts to create a cohesive whole, it is really about building trust and empowering the customer.

Case study: ADM Better product protection was the main reason ADM chose a dome for its coal cogeneration plant in Clinton, Iowa. According to ADM Clinton Cogeneration's Plant Manager, Kevin Duffy, ADM has always stored coal inside some sort of structure to manage dust, but selecting a dome from Dome Technology was an improved means of maintaining coal quality. The dome’s

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Sean Timmins, Orion, USA, considers five ways frontline collaboration is key to transforming mining operations.

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ising costs, supply chain constraints, and the ongoing need for sustainable development and growth are placing tremendous pressure on mining operations to increase workforce productivity, while emphasising the tandem priority of improved workplace safety. Today’s mining companies need new methods and new ways of thinking to meet these ever present operational and workforce imperatives.

The solution: digital transformation Embracing digital transformation and new digital technology provides a long-term path to building resilient businesses focused on improved productivity and safety. In fact, BHP stated in its 2020 annual report: “Technology is a key lever for BHP to improve frontline safety, increase productivity, reduce cost, build capability, and accelerate value creation.”1 Mine sites are some of the most demanding operating environments in the world and require unique approaches to realise the benefits of digitalisation. Complex underground tunnel systems require careful planning and critical safety measures, and the footprint of opencast mines continually

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changes over time. Workers must always be heads-up and aware of their surroundings and heavy machinery.

Mining enterprises seeking to benefit from digital transformation need to equip their frontline workforce with modern communication technologies designed for these environments. Geologists, surveyors, truck operators, machine operators, mechanics, electricians, technicians, blast crew members, supervisors and more, all of these frontline mine workers need the ability to communicate and connect to others off and on-site.

However, mining enterprises need more than just reliable communications to enjoy the advantages of digitalisation.

They need a connected, empowered frontline workforce to truly innovate and drive digital transformation organisation-wide. Today’s collaboration technology delivered on secure push-to-talk (PTT) smart devices meets this need to transform the frontline mining workforce by modernising communication and redefining best practices for safety and productivity.

The following are five ways mining companies can transform their frontline operations when they equip their workforce with collaboration technology.

prevent visibility into worker locations. Real-time location and mapping of workers are critical to effectively overseeing daily operations and responding to emergencies.

Open mining location services are enabled based on global positioning systems (GPS) and other sensor data on handheld devices. Subterranean location services can be enabled with the availability of mesh nodes, access points, or Bluetooth beacons within the mine.

Advanced location services enable managers and supervisors to track the location of workers for safety, to reassign tasks, redirect traffic, or provide emergency assistance. Advanced location services increase visibility into where and what workers are doing at any given time, especially in urgent situations, increasing coordination and accountability. Knowing the real time locations of workers is a critical component of saving lives when the unexpected happens or things do not go as planned.

Increased productivity with process automation

Digital transformation with intelligent collaboration solutions offers new opportunities to increase safety and productivity with process automation. Workers in Operational command and control dangerous work areas are able to remain heads-up and Mining operations are inherently complex and often operate focused on the task at hand. in remote locations. These remote mine sites rely upon a Voice-first collaboration technology available at the distributed workforce with pit-to-port operations and point-of-work on smart devices automates standardised logistics managed hundreds of miles away. Mining leaders checklists, operating procedures and compliance forms, need centralised visibility that connects a distributed eliminating paper checklists and recording and logging workforce and operations to their organisation in real time answers for analysis, response, and review. When process – whether they are in the mine or loading trains in the automation removes the burden of routine tasks, workers railyard. can focus on higher-value tasks.

Collaboration technology, available both on PTT-enabled For example, paper-based checklists are often manually smart devices and browser-based dispatch consoles, entered into a computer, consuming valuable time and enables managers and supervisors to observe wasting resources that could be spent on higher-value communication traffic and coordinate teams in real time, no activities. In other cases, these checklists remain on paper, matter where they are. Managers also gain organisational never entered into databases, which leads to valuable visibility, connecting directly to headquarters and regional information that could be used for analysis and continual or local team members. process improvement being neglected. Seamlessly At the mine site, opencast mines cover miles of digitalising these records enables supervisors to identify ever-changing terrain, and underground mines are a common issues that, for example, can cause equipment complex network of tunnels hundreds of metres deep that deployment delays or shift-change bottlenecks.

Here is an example seamless digitalisation in action. Say, a vehicle operator conducts a routine equipment inspection of a haul truck or power shovel prior to operation and notices that the machinery needs maintenance. Using a voice-activated workflow, the operator is able to log the issue, initiate a work order, deploy maintenance personnel, and update their manager.

Automated maintenance workflows save valuable time across the organisation for expensive equipment, such as: conveyors, ventilation systems, machinery, and more. Haul trucks and power shovels are multi-million dollar pieces of equipment. Every minute they remain out of service can cost companies thousands of dollars, but automated processes can help reduce Figure 1. Geofenced voice alerts issue instant instructions when workers this machine downtime. enter geofenced hazard zones.

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In another example, when a driver moves a haul truck out of a geofenced mining area, conveyor operators can be automatically notified of its pending arrival and activate the conveyor. When the hauler re-enters the geofenced mining area, the shovel operator can be informed of which truck is returning. Automating communication processes saves time and increases productivity.

Intelligent collaboration solutions also automate language translation, increasing productivity by allowing workers to receive communications in their own language.

Language translation capabilities are more important than ever, as global mining companies rely on increasingly diverse teams and international contractors.

Increased safety in urgent situations Rapid response and real-time information in urgent situations are mission-critical for the mining industry, and key to increasing miner safety. Modern collaboration technology helps workers in dynamic situations by providing instant and accurate intelligence with always-on, automated panic alarms, man-down alerts and lone worker safety protocols, which can be automatically or manually triggered by commands, events, or actions.

For example, in the event that a lone worker is injured or unable to move, they could simply say “help-help” to trigger a predetermined workflow that alerts and deploys the closest workers, safety personnel, medics, and site managers to the worker’s whereabouts. The system alerts personnel and notifies supervisors or first responders, whether they are off or on-site. Intelligent collaboration solutions record the metadata from incidents, tracking and storing information like response times, location, workers on-the-scene and all communications, in order to simplify and automate incident reporting and auditability.

Automated workflows can also be initiated by the movements of workers. A lack of detected movement by workers could be indicative of incapacitation. Sustained non-movement can trigger a workflow to request a voice check-in from the worker, prompt personnel in the vicinity to investigate, or deploy safety resources to that worker’s location.

Similarly, dangerous areas or work zones can be geofenced to automatically detect workers’ entrance or departure and initiate safety check-ins or automated voice-walk-throughs of checklists. If a worker fails to respond, remains in the area for too long or stops moving, workflows can trigger safety protocols to automatically send assistance without requiring a verbal response.

Limited-access areas can also be geofenced to notify when personnel enter or leave a secure location.

Safety workflows are always-on, ready to alert supervisors and team members to a worker’s exact location, deploy immediate assistance, and record and archive all activity for subsequent review.

National Outlook for 2021’, which notes that enrolment in Canadian undergraduate programmes focused on mining engineering fell by 33% from 2015 to 2019.2 Finding a skilled workforce will continue to be a challenge for the industry, forcing companies to adapt innovatively. Collaboration tools connect workers with back-end systems and resources for information retrieval, amplifying intelligence at the point of work.

Intelligence amplification reduces training time and ensures all workers have access to critical information, wherever they are. Employees, including new workers and contractors, can have immediate access to the information they need to do their jobs and get up to speed quickly.

Managers can also share their collaboration platform with contractors, allowing them to access critical information quickly and communicate or integrate with existing groups, subject matter experts (SMEs), backend systems, and knowledge bases.

Seamless operations in edge and challenging environments Connectivity for PTT on smart devices, applications, and browsers will always pose unique challenges for organisations operating in remote locations. Underground mines with shafts, stopes, ramps, and pillars create further connectivity challenges. Opencast and underground mines require careful consideration of available networking technologies to ensure communications are reliable and always on.

Mining operations have the potential to lose millions due to downtime from technology not designed for remote, hostile environments.

Software-as-a-service-based solutions, such as collaboration software, require internet connectivity – whether it is with 3G or LTE, Private LTE, Wired Backhaul, Satellite Dish, or BGAN. When these are not available, the solutions must be deployed on-site, or on local networks. In either instance, devices on-site will need to use WiFi in areas where 3G and LTE are unavailable, including underground.

Collaboration technology for mining organisations must be able to operate on the edge with functionality that is highly available, secure, and reliable.

The future of collaboration in mining As mining organisations invest in digital initiatives across their supply chain, they will only realise the full benefits of organisational transformation if they invest in technology that empowers their frontline workforce.

A connected workforce from pit-to-port, or from the mine site to headquarters, creates an agile, digital enterprise ready to respond to evolving needs and capitalise on opportunities.

Today’s mining enterprises have the opportunity to transform their operations and gain a competitive advantage with intelligent collaboration technology.

Empowering workers with information

References

In many places around the world, the mining workforce is shrinking as workers seek jobs in other sectors. One example of this can be found in the Canadian-based Mining Industry Human Resources Council’s ‘Mining Year in Review:

1.

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2.

'Annual Report 2020', BHP, bhp.com/investor-centre/annualreport-2020/ 'Mining Year in Review: National Outlook 2021', Mining Industry Human Resources Council, https://mihr.ca/news/ mining-year-in-review-national-outlook-2021/

James Trevelyan, Speedcast, UK, provides insight into how the Connected Mine can revolutionise the mining industry.

H

aving already undergone decades of change to improve safety and productivity levels, the mining industry is no stranger to transformation. It has been predicted by McKinsey and Co. that digitalisation will not only put predictability within the grasp of operators, but offer the sector an economic impact worth US$370 billion/yr globally in 2025.1 Technology, when utilised the correct way, has huge potential to

make mining big business once again, through the optimisation of operations.

Digitalisation is already paving a way forward, revolutionising the industry in a way that has never been seen before. Some operators are already starting to take notice, with estimates that the worldwide automation market for mining will grow at a rate of 7.3% compound annual growth rate (CAGR) over the

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next five years.2 This shows this is a trend that organisations cannot fail to ignore, with technological adoption increasing in popularity. Failure to comply will trap businesses into an ever-declining cycle where prices remain high and efficiencies are not maintained.

A real need for digitalisation There is a clear need for technology and the benefits it can bring. The business of mining is facing increasing pressure, as companies struggle to boost productivity levels and cut the rising costs of operation. With many mines maturing and ore grades declining, levels of exploration investment have also fallen significantly.

According to Ernst and Young, despite some recovery in the last two years, budgets now are half of what they were in 2012.3 On top of this, worldwide mining operations are almost a third less productive today than they were a decade ago, as mines juggle finite levels of resources with a declining workforce.1 Achieving a breakthrough will take more than just money, instead a radical breakthrough is needed, and digitalisation will be the answer.

However, only seven of the top 40 mining operators have a chief technology officer, chief information officer or chief digital officer in their senior management team, highlighting that digitalisation has yet to become a

Figure 1. From automated vehicles using GPS and wireless sensors to workers using wearable technology, the Connected Mine drastically improves the process.

major priority.4 It seems a breakthrough in the thinking of how mining makes use of technology is needed. Miners need to look beyond their backyard to discover the range of benefits that the digital world and Industry 4.0 has to offer.

This being the case, there are already some players in the mining industry that have embraced digitalisation.

For example, in 2019, Rio Tinto announced the launch of the industry’s first autonomous railway network to transport iron ore to the company’s ports in Western Australia, saving the organisation time and money.5 Furthermore, at the Syama Complex in Mali, Resolute Mining uses automation within its drill equipment and automated vehicles to extract 300 000 oz/yr of gold, boosting its operational efficiency by 30%.6 Incorporating technology using robotics allowed the company to train native Malians to do the work, rather than relying on experienced miners with training and extensive knowledge of drill operations.

The Connected Mine For operators wanting to take similar advantage of technology, they should look at incorporating elements of the ‘Connected Mine.’ This concept sees a mine harnessing a range of integrated solutions, such as: the Internet of Things (IoT), mining machinery, surveillance systems, ventilators, and autonomous vehicles. Data is drawn from all of these solutions and subsequently used to improve every aspect of operations, by making each mine part of a comprehensive management platform. This ensures that managers have access to all the information and online services they require, in order to make the important decisions needed to support and protect on-site workers and assets.

From automated vehicles hauling ore while navigating rough tracks with the assistance of GPS technology and wireless sensors on the ground, to wearable technologies which monitor where workers are on-site via radio frequency identification, technology can be adopted in many ways. Telematics provides predictive maintenance schedules for vehicles and surveillance systems monitoring for potential hazards. Not only do these drastically improve safety, but they also dramatically improve productivity and operational efficiency, lowering running costs and boosting profits, but also revolutionising the business of mining.

Mission-critical communication

Figure 2. The Connected Mine puts predictability within the grasp of managers, giving them greater control and allowing for better decision making.

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The Connected Mine only works if reliable, affordable, high-capacity communication is made available. For all the benefits to be unlocked, connectivity needs to be reliable, with no interruptions, as managers rely heavily on the system’s ability to draw massive amounts of real-time data. The design of communications infrastructure and the management of networks is essential to the safe, productive running of the mine.

With mine sites often being remote, several technologies must be integrated together to provide the high-performing connectivity required.

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The experience in mines and quarries brought to define digital technologies and a smart working method that increases jobsite efficiency, meaning more digging hours on working shifts.

Connectivity needs to incorporate a few key elements, including:

LTE technology Wi-Fi is essential for communication between devices and people on-site, in order to keep daily operations running safely and efficiently. However, this can prove problematic with accessibility being balanced with short range and lower power. To overcome this, the staple of point-to-point microwave has been swapped for long term evolution (LTE) technology. Providing long-range coverage that can penetrate thicker walls and barriers, that is ultra-reliable with high bandwidth, private LTE is now the preferred option for operators. Speedcast works with Nokia to provide the Digital Automation Cloud, which uses LTE to interconnect all aspects of operations, acting as an efficient management platform for all IoT and automation applications.

Satellite connectivity Satellites offer the most affordable method for hard-to-reach remote mining sites. Some mines are able to install optical fibre with backhaul as a back-up, and some rely on it for their base layer of communications. Providing this connectivity, however, requires a network of teleports, satellites, fibre and high-performance cellular base stations, as well as high bandwidth peering with a variety of networks to guarantee connectivity to the rest of the world.

Making an impact The largest global gold mining operator, Newcrest Mining, has demonstrated the impact technology can have.7 In Australia, over 100 000 sensors have been used to create digital twins and build predictive maintenance models.

Newcrest's chief information officer reports these initiatives saved the company over AUS$50 million during 2018. Moreover, at the Hecla Mining Co. in Canada, an extra hour per day was added to operations through technology being incorporated into machinery and vehicles, reducing downtime and allowing issues to be diagnosed immediately.

Huge advantages have also been seen at Telstra in Papua New Guinea, which has used connected and automated excavators, bulldozers, and excavators to drastically improved levels of safety.8 The deployment of LTE has also delivered significant performance improvements, and is designed to meet the mine’s long-term plan with reliable, fast connectivity with low latency.

Conclusion

Supporting a variety of satellite bands, cellular service, optical fibre, and microwave links these multi-mode terminals are essential for the seamless connectivity for mine communication networks.

As the industry continues to see prices falling and productivity slowing, it is imperative managers have access to technology which puts predictability within their grasp and grants them a degree of control. The Connected Mine, with all its different elements, revolutionises the business of mining, enabling sites to become profitable and more efficient in their operations.

In the future, utilising digital technology will have huge benefits in terms of reducing hazards, improving bottlenecks, as well as combatting other issues. Managers being equipped with deeper insights signals a bright future ahead for the whole of the mining sector, facilitating the best use of assets and employees.

Smart network management

References

With so many methods of connectivity, smart intelligence is critical for identifying the available transmission routes that offer the best price performance ratio. Using technologies, such as software-defined wide area networks (SD-WANs), in order to automatically analyse and manage data among routes, offers the best possible performance and provides reliable service with better utilisation of bandwidth. A management platform can also provide end-to-end visibility into remote sites and applications, as well as cybersecurity with direct connection to cloud services.

With most mines having a long life cycle, well-designed communications should cover the entire process and adapt to the mine’s changing requirements quickly and efficiently. During the exploratory stage, a very small aperture terminal (VSAT) in a box offers local Wi-Fi, cybersecurity, and optimised file synchronisation. Later on in development, LTE, fixed VSAT, and broadband global area network (BGAN) systems support asset tracking, IoT, and video surveillance. During the extraction phase, the priority is focused on communications by Wi-Fi, private LTE and two-way radio, in order to ensure high performance for IoT and autonomous parts of the Connected Mine.

1.

Backhaul access terminals

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2.

3.

4.

5.

6.

7.

8.

‘How digital innovation can improve mining productivity,’ McKinsey & Company, www.mckinsey.com/~/media/McKinsey/ Industries/Chemicals/Our Insights/How digital innovation can improve mining productivity/How_digital_innovation_can_ improve_mining_productivity.pdf ‘Mining Automation Market Size, Share & Trends Analysis Report By Solution (Software Automation, Services, Equipment Automation), By Application (Metal, Coal, Mineral), And Segment Forecasts, 2018 – 2025,’ Grand View Research, www.grandviewresearch.com/industry-analysis/miningautomation-market ‘Top 10 business risks and opportunities – 2020,’ EY, www.ey.com/ en_gl/mining-metals/10-business-risks-facing-mining-and-metals ‘Mine 2019: Resourcing the future,’ PWC, www.pwc.com/gx/en/ energy-utilities-mining/publications/pdf/pwc-mine-report-2019. pdf ‘World-first autonomous trains deployed at Rio Tinto’s iron ore operations,’ Rio Tinto, www.riotinto.com/en/news/releases/ World-first-autonomous-trains-deployed ‘What does the future hold for automation in the mining industry?’, NS Energy, www.nsenergybusiness.com/features/ automation-mining-industry-future/ ‘Leading with Industrial Internet of Things to drive data science initiatives,’ Insight, au.insight.com/en_AU/content-and-resources/ case-studies/newcrest.html ‘Three private LTE deployments in the mining industry,’ Enterprise IoT Insights, https://enterpriseiotinsights. com/20191017/channels/fundamentals/three-private-ltedeployments-in-the-mining-industry

Mark Roberts and Rahul Suhane, Maptek, outline how digitalisation is the key to unlocking the value of drill and blast, and how all sources of data can be tracked upstream and downstream and integrated into a single source of truth.

M

ines operate around productivity, performance, and profit. Safety and certainty are key drivers for continuous improvement. The need to accurately track and reconcile operational performance across the mining value chain is driving a revolution within the industry, as awareness grows that success hinges on an understanding of the impact of various factors at specific stages of resource recovery.

Drill and blast is an important value driver for mining operations, representing approximately 20% of the cost per tonne, but it is not an exact science. Rather, it is mostly an empirical exercise, where operations learn from previous experience and each site develops its own understanding of how its geology behaves and reacts to explosives.

Digital systems are important in providing the necessary feedback loop for continuous improvement – helping operations to carry out drill and blast activities smarter and safer. Maptek has found that, on top of refining day-to-day drill and blast, digital systems such as Maptek BlastLogic are improving associated processes and opening doors for innovation in the field.

Why digital?

Many existing methods are a one-way street. Digital systems make them two-way, providing the feedback loop needed to improve outcomes. This improvement can come

about manually, where engineers look into past data and make adjustments, or it can arise from applying predictive analysis with new machine learning paradigms, which look into past data and outline what is likely to happen in the future.

Digitalisation also provides near-live information on the bench to drive compliance to plan. Without the data feedback loop there is nothing to learn. An operation can still run but there is unlikely to be ongoing improvement, and latent value that could have been unlocked gets lost in the dirt. Losing as little as US$1/t makes a huge impact when considering mines that ship millions of tonnes per year – US$1/t saved, or extracted, obviously means millions of dollars on the bottom line.

Digitalisation facilitates better integration between drill and blast and upstream information, such as resource models and mine plans, and boosts reconciliation of downstream processes, such as: dig rates, crusher throughputs, and vibration events.

Recording information on sheets of paper, which get filed never to see the light of day again, is rightly becoming a thing of the past, as digitalisation brings greater insight, transparency, and accountability.

Taking into account all of these considerations, it makes sense to acknowledge that data is king, with connected digital systems providing a single source of truth to work from.

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Unlocking value Not every operation uses digital methods in the same way, but the one thing the operations using BlastLogic have in common is that they are unlocking more value by doing so.

Within the industry, there are many different value drivers. Many operations find they can get quick wins on the board through going digital. For example, in the first week of deployment, a mine was able to simply spatially identify and rectify the fact they were overloading holes by 20%.

Some mines have an obvious problem, with difficulty around accurate charging and an inability to track performance against design. Getting a handle on their drill data is a primary reason they choose the drill and blast design and reconciliation system.

At mines where the drill and blast processes are poorly defined, the design and the execution are not aligned.

When planning teams and operational crews are not on

the same page, it can result in poor blast outcomes, compliance, and quality control.

These outcomes dictate the need to do things better, and the industry is now alert to systems that allow them to do so. However, operations must consider how well the new applications will integrate with their existing processes or systems, and how to properly implement change management.

It is rarely a case of ‘one size fits all’. When it comes to BlastLogic, operations have similarities and differences in how they deploy and support the system. Many use the system itself as the single source of truth. For others, it is a tool in coordination with other systems to feed into a data warehouse, which forms the single source of truth. For example, customers employing autonomous drill rigs achieve a very low as-drilled error rate, and therefore do not use BlastLogic for automatic validation of drill accuracy.

Beyond the average Looking solely at the aggregation of performance across an operation can potentially mask issues, especially with drill and blast. On average, the data may indicate that performance is within specification, so it looks like everything is running fine. At a more granular level, such as the explosives deck, a blast may contain overloaded and underloaded sections. Left unchecked, this undermines the productivity, cost, and safety drivers of a mine.

Digital systems make it easier to identify trends and watch for anomalies. This is where the adage of a picture conveying a thousand words holds true. For example, a digital heatmap generated in BlastLogic allows simple correlation and visualisation of where the issues lie.

Figure 1. Sampling crews can conduct blasthole sampling with Highlighting the data that is out of specification and the BlastLogic Tablet linked to a portable barcode scanner, finding the root cause can help eliminate blame-shifting with sampling records synchronised with BlastLogic Server for analysis and reporting. across teams. It also brings the issue to light in-shift, where updating charge rules or plans, for example, can actually make a difference, rather than waiting for end-of-period reporting.

Technology is the enabler to tighten this coordination and, while it does not always happen immediately, systems such as BlastLogic help align teams in a manner that is mutually beneficial.

Personnel can move away from demarcation of roles and into a true teamwork model, with hard data trumping opinions and guiding Figure 2. Digital data flow supports decisions in drill and blast in response to dynamic real-world best practice. conditions.

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Change management One common factor which can create resistance to adopting a new digital system is the perception that personnel performance is being audited.

It is therefore important that the system offers benefits for the day-to-day field operators. Going digital means operators have the maths done for them on the fly.

Systems, such as BlastLogic, recalculate a charge plan based on different hole geometry, calculate a top-up deck, or work out how much explosive to use when a hole requires different product to design, based on site rules.

Making these jobs easier helps achieve buy-in from individuals and teams, driving better overall results.

This pull-factor for operators to use the system to record data closes the feedback loop with engineers, who can then start to really understand the effectiveness of their designs. Engineers can also see first-hand how accurately their designs were executed along with the blast outcomes.

For example, when measuring vibration rates around heritage areas, they can pose questions such as: Was it exceeded? Did operators honour it? In protecting the heritage area, was a good enough fragmentation achieved in order to avoid secondary blasting? Answering these questions informs the learning through experience that epitomises the empirical science of drill and blast.

BlastLogic fits into the complexity of mining operations.

Users see the benefits on the ground and how it helps

them make better decisions in a streamlined way. ‘If this, then that’ scenarios are simply captured and communicated, removing the clunkiness of paperwork.

Seeing the bigger picture Many customers are now pushing the envelope in terms of how digital visualisation can drive safety and efficiency.

Data analytics and reporting teams are able to create a web interface showing a map overview of working mine areas and overlay it with information based on the status of drillholes and data, such as 3D exclusion zones. This contextual schematic informs other functional teams of the drill and blast activities near infrastructure, such as railway lines. Coordinated planning of blasting times with train schedules ensures correct timing to minimise disruption to product movement and the impact of blasting on critical infrastructure.

Such planning is complex, time consuming and near impossible to display clearly using non-digital methods.

Beyond drill and blast A digital approach proves valuable for processes complementary to drill and blast. For example, BlastLogic can now be used for geological sampling of drillholes.

While not a drill and blast function as such, there is a synergy with drill and blast because it is a form of short-interval control to identify holes available for sampling. Samples are recorded using BlastLogic and then

flagged as being ready to be passed back to the drill and blast crews to continue the quality assurance/quality control (QA/QC) or loading of holes. BlastLogic's ability to be customised for such augmented cases allows mine sites to be efficient, with use of a single system and a data collection point rather than maintaining parallel systems acting on the same data.

Another example is managing geothermal risk, where a specialist team responsible for measuring and tracking hole temperatures may collate and interrogate the data using the BlastLogic Tablet and analysis tools.

On bench integration Integrated drill and blast management systems and mobile processing units (MPUs) are now available to streamline processes and increase the integrity of data collection. The BlastLogic Tablet communicates directly with MPU or truck control systems.

This serves as an important first step in holistic digitalisation from the mine office to the bench. The explosive deck to be loaded is selected and sent to the MPU control system, which loads the hole. Operators no longer have to manually enter the amount of product that

goes into the hole into the truck control system. Removing the manual data entry step means higher data integrity and minimises the risk that the data is not recorded at all, due to the operator being distracted or too busy.

While this automation is important for some customers, Maptek is now exploring advancing MPU integration functionality to include additional MPU data that is of value to be digitalised for analysis and reconciliation. For example, open cup density samples – a fundamental QA/QC check for every MPU load of explosives. This is an even more granular level of data, and is important because if an MPU is out of calibration it may be loading the wrong mix of product, heightening the risk of fume, fly rock, and vibration issues.

There is unlimited potential for improving processes through data-driven decision making, facilitated by digitalisation.

Changing the game

Site practice for generating a charge design has traditionally been based on rule-of-thumb and gut-feeling, followed by time consuming checks to manage confinement. Adopting a digital system lays the foundation for mines to simplify and optimise the process through custom scripting.

An example of digitalisation solving complex problems can be seen in Maptek’s work using scaled depth of burial calculations (SDOB) for coal customers. The company designed an algorithm whereby desired SDOB values are input to determine the correct explosive position to achieve the user-specified confinement. The algorithm-based process performs complex iterative calculations for the engineers, so that they can make high value and efficient decisions.

The biggest benefit is in saving time and Figure 3. On screen visualisation clearly indicates where blast holes are not removing variability around blast confinement drilled or loaded according to plan. and coal seam protection.

Rather than calculating the SDOB values as a manual ‘check’ for charge confinement, the drill and blast engineer now simply specifies the desired confinement values, and BlastLogic calculates the charge plan that will achieve the required result.

In complex scenarios, one day’s work can now be accomplished in minutes.

Therefore, through digitalisation, decision makers can analyse historical performance, react in a timely manner to unplanned events, and plan Figure 4. 3D flyrock modelling can be applied on both planned and actual charging data, enabling for continuous improvement. operations to create safe exclusion zones.

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Dr Anthony Konya and Dr Calvin Konya, Precision Blasting Services, review some new methods for precision presplitting optimisation.

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he ability to accurately and dependably presplit a final face is of extreme importance for the safety and economic viability of a mine. A proper presplit face is often attributed for reducing the likelihood of rockfalls from a project, but a deep understanding of the actual benefits is critical – not only in relation to the impact on safety, but also on capital and operating expenditures. Presplitting, in and of itself, is an expense for a mine, which can substantially increase the cost of the drilling and blasting programme, however, no mine-to-mill optimisation programme can be complete without an accompanying study on the economic benefits of presplitting. A presplit has three major functions at a mine, which will be discussed at length in this article.

These objectives are: To reduce the rockfalls from a final face, which increases safety and reduces operating costs of clearing catch benches and catch berms.

To allow for steeper face and pit angles, which increases overall profitability of the mine site.

To complete the required objectives for the lowest cost achievable.

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Reduction of rockfalls The first objective of a presplit is to minimise the amount of rockfalls that occur from the final face – this is often discussed in how ‘clean’ the face is following the blast. The industry has a baseline understanding that the larger the percentage of half-casts (half borehole marks) left on the face, the better the presplit performs. A general industry rule of thumb is that if the presplit leaves over 90% of the half casts compared to the half casts that were drilled, then the presplit is successful. While a bit rudimentary, this method seems to be a reliable indicator of the number and the size of the rockfalls that will occur over a given amount of time. This is because the presence of the half-casts shows that the blast did not significantly overbreak into the rock mass behind.

The 90% half-cast rule is derived because it is the point at which the majority of rockfalls are eliminated from poor blasting conditions; not the point at which presplitting overcomes the geologic reasons rockfalls may occur, such as weathering mud seams or wedge jointing exposing on the face.

It is critical to understand that blasting will not put rock back together or solve geologic situations, but it can avoid worsening the geologic situations.

Two simple reasons exist for insufficient half-casts, in absence of geologic structural considerations. The presplit is either too ‘light’ (underbreaking with too little power) or too ‘heavy’ (overbreaking with too much power). The use of solely

Figure 1. A project undertaken by Precision Blasing Services in Virginia, US.

the word power, and not explosive power, is intentional and necessary because the design of a presplit is not as simple as a consideration of the explosive load. The consideration of the proper power of the presplit has then been well tied to the geologic matrix, more specifically the rocks Young’s Modulus.1,2 If it can be assumed that all other variables in the presplit formula are held constant, then the power of the presplit is solely a function of the explosive load. In this case, the explosive load can be correlated to the rock mass. The explosive load can then be calculated based on the given scenario to provide the proper presplit and half-cast percentage. The explosive load can then also vary in the borehole when different geologic domains are encountered.

For example, in one project construction in Virginia, US, five different sedimentary rock types were encountered, including: limestone, sandstone, siltstone, mudstone, and shale. The explosive load was modified in the borehole based on the drill cuttings to achieve above a 95% half cast percentage; one blast section is shown in Figure 1.

Slope and pit steepening Two major considerations are made by the geotechnical and design team for a given mine: the face angle and pit angle.

These will be used to ensure face and pit stability and are complex and multifaceted decisions, combining the need for safety (which improves with flatter slopes) with appropriate economic considerations to make the orebody profitable (which improves with steeper slopes). To grasp a general understanding, the face angle is typically set back (flattened) for two reasons: (1) it can help alleviate slope failures; and (2) it reduces the number and size of rockfalls that occur. When mining with competent rock, the primary reason the face angle is decreased is to reduce the number and size of rockfalls. This alone often flattens the pit angle for orebodies and leads to mining additional waste; but the problem is exacerbated because the flatter the face angle the larger the catch bench/berm area for mitigating the rockfalls which do occur.

This means wider catch benches and catch berms in locations where personnel and equipment will operate, further increased pit angle, and the requirement of additional rock removal. The first step in the slope steepening programme is to reduce the overall number (and size) of rockfalls through a proper presplit design, focusing on the power to Young’s Modulus relationship.

The second part of a slope and/or pit steepening programme (slope steepening) involves increasing the slope angle through a reduction in the risk of a slope failure. The major impact that blasting has on this process is not in improving slope stability, but in not worsening the slope stability. To accomplish this, two separate situations arise which need to be considered independently. These broadly can be differentiated as the structural and depositional problems that impact the blasting process.

Joint orientation Figure 2. Precision presplit design with spacing variations to explosive load.

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The structural problems are traditionally based on jointing, but may involve bedding and depositional cases. The traditional problem is with

vertical or near vertical jointing which intersects the presplit plane. Working with perfect vertical jointing, which is dipping at a 90˚, will be used to simplify the discussion; understanding that near vertical jointing dipping at other angles will have similar but more complex effects on the presplit formation. Depending on the strike angle of the joint(s) and the strike of the presplit plane, various situations can present themselves with varying effects on the presplit. These situations are based on work by Worsey and can be summarised as:3 Joints that have the same strike as the presplit plane result in the best presplit formation with no adverse effects.

Joints with a strike angle which is less than 15˚ from the presplit plane striker result in extremely poor performance and likely no presplit plane will form.

Joints with a strike angle which is between 15˚ and 60˚ from the presplit plane strike will result in overbreak beyond the presplit line in-between boreholes as the presplit breakage plane typically intersects joints at a 90˚ angle.

Joints with a strike angle between 60˚ and 90˚ from the presplit plane will result in better performance with some minor overbreak; however, the presplit power will have to be greater to compensate for the joints stopping the fracture process.

Joints with a strike angle 90˚ from the presplit plane will result in good presplit performance, but the presplit power will need to be greater to form full fracture.

This discussion has focussed on joint orientation to the presplit plane, which is important and oftentimes focuses on the design of the mine. The blasting team needs to understand the limitations involved, but, in most cases, they do not have the ability to make changes to the wall design or location. However, another important feature with the geologic structure does have a direct impact on the presplit design – the joint frequency.

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The joint frequency The joint frequency, in blasting, is typically referred to as the number of joints between two blastholes in a presplit line. The considerations of appropriate joint frequency require knowledge of the intended results of the presplit, the joints strike compared to the presplit plane strike, and other geologic features, such as weak seams which may need to be protected against. However, a general rule of thumb is that the joint frequency should be 2 – 3 for a good, long-term presplit and 3 – 5 for a short-term face.

The blast design cannot change the frequency of the joints in a rock mass, but it can select the spacing between boreholes to control the joint frequency, and this will be the major consideration for ensuring good presplit formation.

The selection of the spacing based on the joint frequency is a common error in the design of a presplit, and is why at many sites a presplit design will work for part of a mine, but not the whole mine. This problem is further compounded by the fact that as the spacing changes the explosive load also must change, and typical design procedures such as

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Split-Factor do not work to produce good results. This often leads mine operators to believe that certain geologic domains cannot be presplit, when in fact, in the majority of situations, the presplit can function effectively, but the tools being applied to the design process are inappropriate. To determine the appropriate explosive load based on spacing, the specific geologic domain and the spacing between boreholes must be taken into account. Techniques such as Split-Factor rely on a linear relationship between the explosive load and spacing, which has been shown to be an inaccurate representation. The relationship itself is actually quadratic in nature, which also has to consider the presplittability of the rock, often denoted by the Konya Presplit Factor. The Split-Factor approach would then either overbreak or result in no presplit development, depending on if the spacing is decreasing or increasing, respectively. Figure 2 shows example relationships for the presplit explosive load based on spacing, when spacing is the only independent variable.

Geologic deposition The final part of the slope steepening programme would be the evaluation of the geologic deposition analysing weak features including open seams, mud/gravel seams, and weakly cemented joints or bedding planes – which traditionally have a dip angle below 60˚ and intersect the presplit plane. The detonation of a presplit results in large gas pressure inside of the borehole and, with too much pressure or too long retention time, these gases can flow into the weak seams and open them further. This can lead to the loosening of large blocks, which will be left hanging on the face. This can then also lead to large rockfalls or slope failures and can often be identified through large tension cracks behind the presplit. In addition, it can lead to faster weathering and increased water flow through the newly opened seams. The focus again is to ensure no movement or opening of these seams to preserve the original geologic strength and avoid degrading the face.

The protection of the weak seams can be accomplished in multiple ways, depending on the strength of the weak seam. In situations where mud/gravel layers or open seams are present, the best practice is to deck through the area, while leaving a small tracer line in the deck and to the second powder column, in order to ensure consistent initiation of the presplit powder column through the entire borehole. Another important feature is to ensure that the stemming retention time is greater than 8 msec. but less than 25 msec., in order to relieve the borehole pressure through venting and ensure that large, prolonged pressures are not realised on the weak seams.

The next step is to then utilise a technique which is now widely adopted in most sensitive presplit environments – precision presplitting. This entire article relies on concepts developed from the technique of precision presplitting, which is a specialty presplit design intended to use rock properties to achieve the desired results. The basis for this is to generate enough borehole pressure to cause the presplit to form by exceeding the rocks tensile strength through a hoop stress field, but not to generate so much pressure that it causes additional breakage, including overbreak and breakage of weak seams. The traditional methods of presplitting rely on utilising such large pressures that any rock will break, and this often leads to massive overbreak in weaker rocks. It is intuitive

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that to presplit a weaker rock, less explosive is needed than to presplit the strongest of rocks.

Precision presplitting The final step of a presplit optimisation programme is to finalise a long-term design strategy which meets the sites objectives, follows the criteria discussed in this article, and achieves this at the lowest possible cost. This is an intensive procedure which is completed through a multivariable blast design process. The first stage is to understand not only the desired site goals, but also the realistic application at the site, including: explosive products, drilling equipment, and blast crew experience. This is critical, because a theoretical design that cannot be implemented is useless. The next part is a deep understanding of the site’s geology and current mining plan. Finally, the design process can begin by not only considering the desired intra-borehole pressure and associated hoop stresses generated, but also the economic considerations. For example, to achieve the same results one can decrease the explosive load or increase the diameter of the borehole diameter. These relationships are non-linear and often require advanced software to analyse, but they can utilise the site-specific costs to develop the most economic solutions, which in turn can be practically implemented to produce the required results.

This process has been repeated at sites worldwide to achieve proper performance while improving site safety, steepening the mines slopes, and decreasing the mine’s presplitting costs concurrently. For example, at a Canadian diamond mine this process was implemented for the first diamond pipe pit. The original design utilised a face angle of 60˚ and benches of 50 ft (15 m). Through this design process, the face angle was steepened to 90˚ and the benches were increased to 100 ft (30 m) in height, while using borehole diameters up to 6.5 in. (165 mm). This also accompanied a steepening of the overall pit angle in both the kimberlite and granite, due to the ability to reliably achieve a competent, and safe presplit plane for the final walls.

Conclusion Precision presplitting is a new technique in presplit blast design which has quickly taken over the blasting industry, due to its ability to work with and use of a mine site's geology. This has allowed for it to be used in everything from extremely weak mudstones and siltstones, up to the strongest of granites, gneiss, and basalts. The technique also has the ability to account for site jointing and structure to minimise backbreak, while ensuring a smooth, clean highwall remains. This had led to large improvements in mine efficiency, including allowing for more stable highwalls and the steepening of pit slopes, in order to reduce overall mine waste. It has also led to major improvements in mine safety, by reducing the risk of rockfalls dramatically.

References 1.

2.

3.

KONYA, A. and KONYA, C., 'Precision Presplitting Optimization', Proceedings of the 42nd International Conference on Blasting and Explosive Technique, (2016).

KONYA, A. and KONYA, C., 'Precision Presplitting - Explosive Variations with Spacing', Proceedings of the 43rd International Conference on Explosive and Blasting Technique, (2017).

WORSEY, P., 'Geotechnical Factors Affecting the Application of Pre-Split Blasting to Rock Slopes', University of Newcastle Upon Tyne, (1981).

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Breno Castilho, Raphael Costa, Evilmar Fonseca, and Paschoal Cataldi, Hydro, Brazil, consider dry backfill as an innovative approach to tailings management in Brazil.

108 September 2021 // global mining review

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he long-term management of tailings generated by the mining industry demands site-specific solutions and systems, driven by all the applicable local regulations, environmental and climate conditions, geotechnical safety, and ore-specific characteristics. Stakeholder expectations are increasingly focused on demanding solutions that will minimise social and environmental impact, including considerations on the current and future use of land.

Innovative technology for tailings management was developed at the Paragominas bauxite mine in northern Brazil. The results of a comprehensive 18-month field trial demonstrated that a technique known as tailings dry backfill could be adopted successfully, offering advantages such as reduced operational risk and reduced environmental footprint.

Since the use of tailings restore the land to its original topography, the ecological rehabilitation of the mine is facilitated.

Norwegian aluminium and energy company, Hydro, currently owns and controls one major mining operation in Brazil: the Paragominas bauxite mine (Figure 1). The Paragominas mine is located in the municipality of Paragominas, state of Pará, northern Brazil. The mine's production capacity is approximately 16 million tpy of run-of-mine (ROM), producing approximately 11.5 million tpy of bauxite and generating approximately 4.5 million tpy of tailings.

The mine started operations in 2007 and was acquired

by Hydro in 2011.

This article will present a new technology of tailings management developed at Paragominas bauxite mine in 2019. Known as tailings dry backfill, this technology backfills tailings that have been previously desiccated in temporary drying areas, on mined out strips, from where the bauxite ore (ROM) has been removed. After backfilling the tailings, overburden is also placed back into the strip – restoring the land to its original topography – and the area is environmentally rehabilitated by planting native vegetation and trees.

Currently, Hydro has achieved a recovery ratio of 1:1, meaning that for every 1 ha. that is mined, 1 ha. is also environmentally rehabilitated.

Tailings dry backfill at Paragominas bauxite mine Boger and Hart state that there is a growing awareness that effective tailings management is essential for creating a more sustainable mining industry.1 This article presents a list from least sustainable to most sustainable standard practices in tailings management (Table 1). According to the list, the methods that most

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negatively impact the environment are direct discharge into a river or the sea. In contrast, in terms of sustainability, the most desirable methods are the re-use of tailings or disposing it into mined-out areas, also known as dry backfill.

Since the central concept in dry backfill uses the physical containment provided by the mined-out pit, the tailings storage facilities (TSFs) then remain on previously disturbed areas, thus reducing environmental impacts and minimising land disturbance.2 From a geotechnical

Figure 1. Paragominas bauxite mine, Brazil.

Table 1. Sustainability of tailings management practices Tailings management practices Least sustainable

Riverine Submarine Conventional tailings dam Central thickened discharge Dry stacking Paste backfill Re-use of tailings

Most sustainable

Figure 2. Paragominas Plateau System.

Figure 3. Tailings desiccation process.

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Dry backfill

standpoint, recent findings from a compiled database of information on tailings facilities found that such facilities report a lower incidence of stability issues when compared to other methods of disposal.3,4 Perhaps more importantly, such an approach helps companies integrate environmental and safety considerations in a manner consistent with continual improvement in their tailings operations, while demonstrating proactivity to regulators, stakeholders, and public opinion in general.5 Taking that into account, Hydro studied alternatives for the sustainable long-term management of its bauxite tailings. The developed solution eliminates the use of conventional dams built for the permanent storage of tailings and, instead, use the concept of tailings temporary drying areas. After the drying cycle, dry tailings are removed and backfilled into existing mine pits.

Different from regular tailings dams used for the permanent storage of tailings, the Plateau System is a temporary area for the drying of tailings, divided into four quadrants – named RP1-A to RP1-D – as well as eight effluent clarification basins. Figure 2 shows a photo of the Plateau System.

The Plateau System dimensions of the quadrants, the positioning of their decant systems, and the spacing between spigots, allow for the adequate drying of the tailings. Its total area is approximately 300 ha., and it contains 142 spigots spaced between 75 – 100 m from one another. The spigot system was designed to avoid tailings grain segregation, and thus enhance tailings desiccation.

The decant system is composed of four spillways, which have the purpose of driving out rainfall water and water released from the tailings, thus helping with the drying of the tailings. The spillways are connected to transfer channels, which flow to the clarification basins – from there, water can be reused in other mining processes.

The bauxite tailings have the following geotechnical characteristics: Specific gravity (Gs): 2.68 Average solids content at disposal (by weight): 35% Final solids content (by weight): 60% Density at disposal: 1.27 t/m3 Density after desiccation: 1.60 t/m3 The tailings are deposited in the drying quadrant in layers of approximately 50 cm that are later exposed to solar drying, allowing tailings to reach a minimum 60% weight solids contents. The tailings are deposited, alternating between the four quadrants to allow enough sun exposure time for the tailings to desiccate.

Drying takes 30 and 60 days during the dry and wet season, respectively. Figure 3 illustrates the tailings desiccation process.

Upon reaching a minimum 60% weight solids contents, tailings are then mechanically removed and transported for final disposal at the mine pits.

The internal separation of the Plateau System in four quadrants allows tailings removal and disposal to happen simultaneously. The minimum solids content of 60% weight increases the productivity in the mechanical removal of tailings from the drying area and also in the disposal at the mine pits. Moreover, this solids content optimises volume usage on the pits. Tailings removal happens by using mine operation equipment, such as wheel loaders and trucks. Figure 4 shows tailings removal taking place in the drying area.

Upon being removed from the drying area, tailings are transported for disposal into existing pits – similar to what is traditionally done for overburden disposal in the bauxite strip mining method. After backfilling the tailings, the overburden is placed on top, restoring the land to its original topography. Figure 5 illustrates the tailings disposal method at the mine pits.

Since it eliminates the need for conventional dams – used for the permanent storage of tailings – it is considered that the dry backfilling of tailings is both the best and most suitable tailings disposal method for Paragominas bauxite mine. Figure 6 shows dry tailings being disposed of at the mined-out strips.

After restoring the mined areas to its original topography – by backfilling tailings and overburden into the pits – the environmental recovery of the area is performed, with the formation of a new ecosystem and biodiversity comparable to what existed before.

Before the vegetation suppression, a forest inventory is carried out to identify the existing biodiversity, which will be used to assess the evolution of the restored areas. Phenological studies are also carried out on endangered species with high conservation value, flora recovery and seedling production, among other actions. Figure 7 shows a mined area that has been recovered.

Monitoring and results A comprehensive environmental and geotechnical monitoring programme has been performed ever since this new technology for tailings management was developed at Paragominas bauxite mine. The goal of the monitoring programme is to ensure the safety and sustainability of the solution.

Since the bauxite ore beneficiation at Paragominas consists only of particle size classification and does not include any chemical process, tailings do not much differ chemically from the ROM. Paragominas tailings are classified as chemically inert according to Brazilian regulations.

Obtained results for groundwater and soil quality are compliant with Brazilian legislation. They are within expected values from the background studies performed before mining activities in Paragominas.

Also, groundwater level monitoring at the mine has not indicated any changes due to tailings backfilling operations.

Dam instrumentation and inspection have not shown any anomalies. Dam instrumentation consists

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Figure 4. Tailings removal taking place in the Plateau System.

of piezometer and water level indicators – readings are compared to a control chart. Every reading during project activities is within expected values. Inspections are carried out fortnightly by Hydro’s internal team, in compliance with Brazilian regulations. Inspections are also performed independently by the dam designer and independent auditors.

Since the beginning of the project, 100% of tailings generated in the beneficiation plant have been disposed of by using the dry backfill method. The method is a sustainable alternative for the long-term management of tailings at Paragominas bauxite mine.

Hydro performed tests with this new methodology for 18 months, and monitored results were shared by the state environmental authorities. After attesting to the geotechnical and environmental safety of the method, Hydro finally obtained the full license to operate in December 2020.

The main benefit obtained from the new technology for tailings management is that it eliminates the need to build conventional tailings dams for permanent storage.

Paragominas is the first Brazilian bauxite mine to operate without building new tailings dams. The reduction in the environmental footprint in Paragominas' case represents an area of 850 ha.

Conclusions Figure 5. Tailings dry backfilling at the mined-out strips.

Figure 6. Tailings disposal at the mined-out strips.

The sustainability of a mine is inextricably linked to positive and proactive practices applied to tailings management. These include taking steps to avoid the unnecessary building or raising of TSFs. By developing this innovative solution, Hydro affirms a position of technological leadership in the mining and metals industry, proactively addressing the unavoidable challenge of managing the tailings generated by its bauxite mine. The main benefits of the tailings dry backfill technology are: Reduced environmental footprint.

Reduced operational risk.

Both benefits arise because permanent tailings storage dams are no longer built or raised in Paragominas. Also, since the use of tailings restore the land to its original topography, the environmental rehabilitation of the mine is facilitated.

References 1.

2.

3.

4.

5.

Figure 7. Recovered area.

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BOGER, D. V., and HART, B. C., ‘Making an unsustainable industry more sustainable’, in 2008 International Seminar on Paste and Thickened Tailings, Gaborone, Botswana (2008), pp. 3 – 5.

HORE, C., and LUPPNOW, D., ‘In-pit Tailings Disposal at Langer Heinrich – Tailings Storage Facilities in a Unique Hydrogeological Setting’, SRK Consulting, (2015), presented at Tailings and Mine Waste Management 2015, pp.27 – 28.

LANE, J. C., ‘In-pit Tailings Deposition; What Have We Learned About This Tailings Storage Option?’, Workshop on Environmental Management, (2008).

FRANKS, D. M., STRINGER, M., TORREZ-CRUS, L. A., BAKER, E., VALENTA, R., THYGESEN, K., MATTHEWS, A., HOWCHIN, J. and BARRIE, S., ‘Tailings facility disclosures reveal stability risks’, Scientific Reports, (2021), Vol. 11, No.1, pp. 1 – 7.

A Guide to the Management of Tailings Facilities, 2nd edition, The Mining Association of Canada, (2011).

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Rob Adam, AESSEAL, explores how re-evaluating the sealing methods on the pumps that feed slurry into the tailings dams is one way in which mining companies can better control water levels and mitigate against risk.

M

aintaining safe water levels in tailings dams is critical to preventing the failures which can cause death and the destruction of local communities and natural habitats. It therefore stands to reason that every opportunity to limit excess water in the dams should be investigated. Re-evaluating the sealing methods on the pumps that feed slurry into the tailings dams is one way in

which mining companies can better control water levels and mitigate against risk.

Increased demand for metals and other minerals in recent decades, coupled with advances in mining recovery technology, has led to a significant increase in the amount of rock being mined, as well as the ability to mine lower grade deposits for materials. However, this has also led to a

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sizeable increase in the amount of tailings that is produced during processing activity – and the disposal of these tailings can have a devastating impact on local communities, the environment and mining operations themselves, if it is not controlled.

Tailings dam failures may not be an everyday occurrence in mining operations. However, it is also true that they are not infrequent enough – and when they do occur they can be catastrophic, with breaches often resulting in loss of life and devastation to the communities and ecological systems in the surrounding areas. A major cause of such failures is excessive water in the dam.

Details of the more than 50 incidents, recorded between 1999 and 2019 across the globe, provide an indication of the destruction caused by tailings dam failures.

One incident, at the Córrego de Feijājo iron mine in South America in 2019, resulted in 246 people killed and 24 reported missing after the tailings wave travelled 7 km into parts of the local community of Vila Ferteco. Key mining structures, other sediment retention basins, and the mining railway branch were also left demolished in its wake.

Responsible mining has become the mainstay and drive of most of the major companies in the mining industry, as demonstrated by the International Council on Mining and Minerals (ICMM) and the establishment of a committee to drive the safe handling of tailings.1 In light of this commitment to improved practices and greater transparency, it stands to reason that mining companies with a commitment to protecting people, natural habitats and the environment, should look at every possible opportunity to mitigate the risk of dam overfill and the danger it presents.

Re-evaluating the sealing systems on slurry pumps might not be the most obvious place to seek answers, yet selecting the right sealing solution can play a significant role in reducing the volume of water added to a tailings dam, thus contributing to the mitigation of risk.

Figure 1. Tailings dam and processing plant

Tailings dam design

Figure 2. Pump with SW3 water management CDSA sealing solution.

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Tailings are pumped from the mine into a tailings dam, in the form of slurry, and left to settle at the bottom, so that the water above can be reused in mining process operations.

Cost is inevitably a crucial factor in the selection of tailings dam construction, therefore raised embankment dams, which have a lower initial capital cost, are the most common design used. Unlike retention dams, raised embankment dams are built in phases, according to the need for additional capacity, using soil, tailings, and waste rock.

Upstream raised embankment dams – which have the lowest capital cost of all – are the most common option in low seismic risk areas, and are also the most likely to suffer structural failure. These dams are designed to hold back solids and retain water up to the lip of the dam. The slurry is pumped to the crest of the embankment where it drains to form a ‘beach’, which then acts as an important buffer between the embankment and the water in the dam. As greater capacity is required, the beach becomes the foundation for extensions to the embankment’s height.

It is important to note that pushing the water to the limits of the dam’s capacity will eventually erode the structure. The key failure mode for upstream structures is liquefaction caused by an excess of water in the dam, which causes the tailings beach to flow, breaching the dam sides, and, in many cases, wreaking havoc.

Efforts have been made within the mining industry to increase stability and improve water retention through design improvements. For example, downstream raised embankment dams are designed to be structurally

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independent of the tailings, but they are more expensive and require more space. Centreline structures can retain more water, though they still rely partially on the settled tailings for stability, and so are still not suitable for retaining a large volume of water.

One simple mitigating action to consider, therefore, is to reduce the amount of water being released into the dam in the first instance. The right slurry pump sealing solution and support system can help to achieve this.

Slurry pumps and water use The mechanical packing, expellers (also known as ‘dynamic’ seals’) and single mechanical seals, traditionally used to seal slurry pumps, require a significant amount of seal flush water, injected from an external source, in order to keep them cool, clean, and lubricated. One large gland-packed slurry pump alone can require up to 180 l/min. at a pressure of 5 bar, equating to more than 90 million l/y. Apply this calculation to a typical slurry application employing four large gland-packed slurry pumps, and the total water used amounts to 1.037 million l/d (378.43 million l/y). Where double mechanical seals are used in conjunction with a quench to drain system, which discards seal flush water at the end of the cycle, water consumption is similarly high.

Taking into account an element of leakage, all of this water – equivalent to approximately 122 Olympic sized swimming pools – is discharged into the tailings dam annually. This has the potential to make a critical difference to water levels.

Reduce the risk and improve pump reliability The collective toll of people reported dead and missing following tailings dam failures exceeded 800 in the 20-year period leading up to 2019 – and this does not include incidents which have gone unrecorded.

The pollution of natural and drinking water by hazardous substances, such as the heavy metals and cyanides contained in some mineral tailings, as well as the destruction of communities and the natural landscape, are additional tragedies which have far-reaching and long-term consequences.

When excessive water levels are a recurring cause of these failures, it is clearly essential that any unnecessary discharge of water into tailings dams should be avoided.

It is therefore worth considering that the amount of water discharged into tailings dams can be reduced by millions of litres a year by employing a dual, double balanced mechanical seal and seal support system on slurry pumps.

Modern double mechanical seals have two sets of faces, one sealing to the process fluid and one to atmosphere, with a barrier space between the two. They are designed to meet the arduous requirements of heavy duty slurry applications, with fortified metal parts which are highly resistant to corrosion and erosion. Large ports and increased radial clearances mean the lubrication, which is vital to optimising seal life, is maintained constantly and consistently.

118 September 2021 // global mining review

A pressurised barrier tank system is central to the environmental sustainability of this solution. This support system employs a thermosiphon process to ensure that the seal faces are lubricated with clean, cool water at a higher pressure, typically one bar, than that in the pump stuffing box. The flush water is constantly recycled, flowing across the seal faces in a continuous loop and reducing discharged waste to the tailings dam to a negligible amount.

The potential benefits in terms of safety and sustainability are clear. However, it is worth noting that this advanced sealing technology brings other significant benefits.

Improve reliability, reduce downtime Traditional sealing approaches such as gland packing have significant limitations. The tight packing around the pump’s shaft creates friction, which causes wear, both to the packing and, in worst case scenarios, to the pump shaft or shaft sleeve.

Leakage is inevitable – bearing failure due to fluid ingress is one of the most common causes of equipment breakdown. Mean times between failure (MTBF) are low and intensive maintenance is needed for packing readjustment and replacement. Friction demands more power to drive the pump, leading to increased energy costs.

By contrast, a dual mechanical slurry seal and support system brings improved pump reliability and lower maintenance costs. The consistent, stable supply of lubrication protects the seal faces, optimising their efficiency and lifespan. It also alleviates process upsets such as operation of the pump away from its best efficiency point (BEP), cavitation, and dry running.

Leakage on a well-designed, specified and fitted mechanical seal amounts to roughly a teaspoonful a day, compared with a leakage of roughly 450 l/m on an optimal gland packing arrangement (based on a leakage rate of one drop per minute of sealed product per 25 mm of outside diameter shaft). Bearings are therefore protected from damaging fluid ingress.

The non-contacting design of mechanical seals means pump shafts are not subjected to harmful friction, so less energy is needed to power the pump – the power consumption of double mechanical seals is estimated at around six times less than gland packing.

Conclusion Cost savings and swift return on investment, coupled with the environmental benefits of hugely reduced water and energy consumption, present a powerful case for considering an upgrade to an advanced modern sealing solution and water management system. However, when that solution also offers the potential to reduce the risk of devastation to lives and communities caused by tailings dam failure, considering it should surely become less of a choice and more of an imperative.

Reference 1.

‘Tailings storage facilities owned or operated by ICMM company members,’ ICMM, www.icmm.com/member-tsfs

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