Sustainable development across the minerals and metals value chain

SME’s Sustainable Development Committee brings together every division in the Society to help transform the minerals and metals industry for the future. SME’s Sustainable Development Committee (SDC) spans every division within SME and thus all aspects of the metals and minerals pipeline from exploration to extraction to impacts on society. The SDC is the only SME committee composed of members from each SME Division. We encourage all SME members to engage in activities that can transform our industry as a future-focused and impactful force for the sustainable development of humanity. The SDC is a resource for SME members for identifying and sharing information on current tools, best practices and new developments on the contributions the minerals industry makes to sustainable development. The goal is to inform discussions and to support applications of these tools throughout the mine lifecycle. This committee, through the SME strategic plan, encourages increased awareness of how the minerals industry can contribute to sustainable development worldwide. As the world shifts to recognizing the increase in raw materials necessary to supply the future needs of renewable energy, global infrastructure requirements and efforts toward poverty alleviation, the delicate balance of increased extractive activities with stakeholders, net-zero strategies and environmental equity is increasingly critical. Sustainable development in the mining industry today thus includes all aspects of materials discovery, sourcing, extraction and supply for the needs of present and future generations. Sustainability occurs through incremental improvements at each step of the mining process and leads to more effective decision making, positive business outcomes, improved investor sentiment, greater societal visibility and a longer-term vision for predicting, improving and mitigating community and environmental impacts, all while building the wealth and supplying the necessary materials for society. Incremental change at each step of the mining value chain creates better practices and greater contributions to sustainable development in and around operations. Future-focused change also offers better engagement opportunities with young professionals who are interested in innovative design to transform the industry, and with the broader public that is largely unaware of industry initiatives. With this integrated approach, we can help SME reach new segments of society who hold creative and diverse perspectives, and who are key to identifying new and innovative solutions for minerals and metals supply, use and distribution. Many topics of sustainability have common threads in the minerals industry — energy consumption and greenhouse-gas (GHG) emissions, water and land use, health and safety, environmental impacts and community engagement — such that improvements along each step of the process are linked in a network of positive developments from ore discovery to mine closure. Stepwise improvements in exploration, blasting, extraction, autonomy, digital transformation, workforce transition, fleet movements, process development and operation, tailings management and elimination, and more, all impact the overall value of a project and its operational, business and stakeholder outcomes. They also provide an opportunity to increase positive visibility and public perception of an innovative mineral resources industry. Readers will be aware of many positive examples in their own fields and across the operational value chain. Our hope is to encourage dialogue among the divisions in SME in connecting such activities through communication, data sharing and aligned purpose as we transform the mining industry into one that is sustainable and dedicated to a better future for humankind. Exploration and discovery Sustainable activities in exploration and discovery are key to the success of a project, since geologists may be the first onsite and will raise expectations and concerns from the first appearance and earliest sampling and drilling, irrespective of the prospect for development. Integrated exploration plans incorporate advanced consideration of future factors that may never come into play but will be on the table from the start: risk potential, sensitive land use, early and transparent community communication and engagement, skill-development plans for locals and environmental impact plans with shared use of water and energy. Predictive tools to inform and assist in the most effective and least impactful development options alleviate fears and lessen the risk of unexpected downstream events. During the front-end loading sequence of studies, characterization of the deposit is essential to mitigate risks: for example, in deleterious element content and waste management from the earliest stage. Reducing potential mitigating factors early on can breed confidence in stakeholders and increase the attractiveness of the project to investors. Effective use of advanced analytical techniques, remote sensing and terrain data analysis, geometallurgical modeling and machine learning methods based on target information can go a long way to lessen surface impacts until activities are appropriately understood, planned for, laid out, permitted and valued (for example, Olson Hoal and Frenzel, 2022). These efforts increase the effectiveness and value of projects for operators and increase transparency, stakeholders’ value and positive visibility of the mineral resources business. A developing example incorporating social capital is the Mt. Milligan project in northern British Columbia, Canada in which community indicators are used to forecast specific social and economic outcomes for new mining projects (Nelson et al., 2010). Mineral processing Mineral processing of metallic and nonmetallic minerals can be understood as a group of physical operations destined to obtain certain minerals and elements contained in rocks in which materials are sometimes mobilized, transformed and consumed. These operations include the comminution for physical liberation of minerals in crushers and grinding mills that may have impacts on the environment, particularly in energy consumption and water use. At face value, these effects are determined by the development of mining operations in terms of scale and geography (operations on increasingly larger scales affecting an everwider portion of the mining regions). Such impacts have been adjusted to the increasingly lower-grade, more-complex mineralogical composition and increasing inaccessibility of ore deposits over time. These technical challenges, which are increasingly complex and demanding, require new technical developments in response to increasingly challenging ores and minerals. Characterizing the ore prior to crushing and grinding, adapting comminution and beneficiation methods to the variability in ore types, using renewable-energy sources and recycled water on site and improving early ore-to-waste separation mechanisms are well-established methods for reducing energy, water, environmental and social impacts in the comminution stage, and toward implementing a circular economy. Examples of incorporating sustainable operational methods into mineral processing include monitoring and reducing GHG emissions associated with primary mineral and metal production (Azadi et al., 2020). The Stillwater and East Boulder mines are shallow- to intermediate- level underground platinum group metals mines situated 136 km (85 miles) southwest of Billings in Sweet Grass County and approximately 57 km (32 miles) south of Big Timber, MT. Sibanye- Stillwater has a good-neighbor agreement signed with the community 20 years ago that has proven successful for both parties. Extractive metallurgy The metallurgy sector is one of the most active sectors working to decrease energyintensive activities, energy transition, water consumption and GHG emissions, as it is a direct target for carbon reduction initiatives worldwide. There are opportunities for companies to make subtle innovations to meet sustainability requirements and to develop more-efficient operations. For example, the pyrometallurgical transformation of iron ore releases a large amount of carbon dioxide (CO2), making iron and steel production one of the largest industrial emitters of GHGs. Novel technological methods, perhaps through the use of hydrogen, may become more acceptable in the future. Some of the best efforts to promote sustainability in extractive metallurgy relate to reducing the consumption of energy and water, for example, in cement production and in copper production. An example of these is the introduction of coarse particle flotation technologies to reduce comminution energy and the use of reclaimed water in flotation. Another example is the increased recovery of energy and gases from production processes, such as flash smelting and converting, along with efficient waste heat recovery and sulfur dioxide capture as practiced at Rio Tinto Kennecott. In addition, the improvement of production technologies has generated opportunities related to furnace feeding and the control and automation of input and product flows, with the objective of providing greater continuity and integration of processes and avoiding energy losses between production stages. Examples of technologies and processes now globally employed to promote energy efficiency in extractive metallurgy include enhanced systems for real-time control of process variables, optimized usage of process gases already used for heat recovery and gas cleaning, new technologies that promote a significant reduction of energy consumption in electric furnaces and electrolytic processes, including the respective automation and control systems, and hydrometallurgical selective leaching and metal separation and recovery systems with zero water discharge and no gaseous emissions. The Sibanye-Stillwater operations in Montana are a key example. Tailings management One of the more publicly visible areas of the minerals industry that sustainable technologies are addressing is in the area of waste rock and tailings management, in part incentivized by the circular economy. Dry-stack tailings, reprocessing of tailings through microbial leach technologies, recharacterization methods and re-evaluation of materials reuse potential all aim to better predict, manage and reduce waste rock and tailings. The Golden Sunlight Mine in Montana, for example, aims to reclaim tailings and send resulting concentrated sulfide materials to Nevada to supplement roaster heat balances. Potential new critical-metals value residing in tailings and the need to reduce environmental risk from waste flows are both driven by characterization and understanding of what resides where in waste materials. The U.S. Geological Survey’s critical-mineral initiative is addressing the location of materials from byproducts (abandoned sites, tailings and waste rocks) in addition to new potential resources through the Earth Mapping Resources Initiative (Earth MRI), Critical Minerals Mapping Initiative and Abandoned Mine Lands programs, as included in the Infrastructure Investment and Jobs Act of 2022. Renewable-energy integration The minerals industry is entering an exciting time with respect to integrating renewable energy into operations, and there are many successful initiatives already in place globally. Mining activities can be energy-intensive, and reliance on power generated from fossil fuels may lead to increased regulatory, financial, community and societal risks. With the world target for a carbon-neutral/net-zero carbon future, and investors seeking environmental, social and governance (ESG) and GHG reporting, opportunities to become sustainable operators exist through cost-competitive renewable sources of power generation such as that implemented at Teck’s Carmen de Andacollo copper operation (Canadian Mining Journal, 2020). Depending on technology and geographic constraints, significant opportunities exist to reduce costs and the carbon and water footprint, and to provide long-term benefit to local communities such as potential revenue streams. Agreements, partnerships and synergistic developments with local energy providers and communities will help in the shift toward mixed energy sources and diversified operations and revenue streams. A sustainable society and the renewable-energy sector that will support it requires responsible mining practices that investors, stakeholders, shareholders and the public are likely to support. Environmental, social and governance factors An important piece of integrating sustainability is to follow reporting requirements and standards and effectively communicate about ESG and materiality to investors, shareholders and stakeholders. Governments and lenders require companies to report on some aspects of ESG and materiality, and industry organizations are encouraging more transparent disclosures. However, this is a complicated task as beyond regulatory reporting requirements there are numerous voluntary standards and guidelines for reporting, and defining what is material to a company and its operations is regionally complex and depends on the type, size and location of operations. For sustainable artisanal and smallscale miners, the task is even more difficult in the absence of large companies (Baena and Mendoza, 2021). Nevertheless, steps are being taken to move toward more standardization in ESG reporting. Through a data-driven approach, Perdeli et al (2021) provided an overview of the scope and consistency of sustainability indicators used in the sustainability reports of mining companies. They demonstrated that internal issues are better represented than external issues, in particular transportation and supply-chain issues. In 2020, the CFA Institute established an ESG working group to develop a voluntary global standard that would allow investors to understand and make comparisons of ESG reporting. In an effort to establish consistency and comparability in companies’ ESG reporting, the World Economic Forum’s International Business Council and its partners published a white paper in which they drew from and expanded existing ESG standards to establish a core group of metrics and disclosures mapped to the UN Sustainable Development Goals (World Economic Forum, 2020). The International Financial Reporting Standards Foundation launched a consultation to assess demand for global ESG standards. The consultation recognized that a set of comparable and reliable standards will provide more transparency and greater assurances. The National Mining Association’s (NMA) newly formed ESG taskforce is exploring the landscape of industry initiatives on ESG. For SME members, the Society has developed an innovative and helpful ESG Toolkit to address these important issues (see https://community.smenet.org/esgtoolkit/. Community engagement and development Community engagement and development are closely linked to ESG performance and are perhaps two of the most important mechanisms through which companies can contribute to sustainable development. The need to engage early and engage often refers to the need for companies to disclose information, participate in dialogue, and listen to and address feedback at the beginning stages of a project and frequently throughout the project’s lifecycle. Efforts to empower communities and build their capacity may be rewarded with more positive outcomes for both parties and improve the company’s capacity to manage potentially impactful events, such as expansion and mine closure. An established example of success in sustainable development is the past 30 years of development and operation of the Stillwater Complex in Montana by Sibanye-Stillwater and its good-neighbor agreement (Sibanye- Stillwater GNA Fact Sheet, 2021). Community engagement and development are often not straightforward, however, and may pose some of the biggest challenges for mining companies globally. Several organizations have created guidelines or toolkits for community engagement and development. They include the Network for Business Sustainability, the ICMM and the Commonwealth of Australia. Each of these resources is useful for establishing guidelines and in some cases, step-by-step instructions for community engagement. Companies also have internal guidelines for operating characteristics and corporate culture, and communities have diverse social, economic, political and historical circumstances. A standardized approach to community engagement and development can thus fall short of addressing the particulars of a project and its context, and may end up as misdirected and ineffective. SME’s SDC welcomes case studies, novel approaches and lessons learned from the larger SME community through which we can learn different methods for community engagement and development, and compile a set of best practices for industry professionals to learn from and use to improve their efforts. What more can SME do? SME’s SDC encourages all members to engage with transformation and to see challenges and inefficiencies as opportunities for creativity and innovation along every step of the value chain. Each change can add up to overall increases in project value, stakeholder gain and a shift in public perception. We invite SME members across the organization to consider broad sustainability initiatives in your areas of specialization, and to join us in transforming our industry to future-focused, sustainably driven and stakeholder-based practices. SME Annual Conference. We invite all SME members to add sustainability issues into papers and presentations for the MINEXCHANGE 2023 SME Annual Conference & Expo in Denver in February 2023, highlighting how sustainable initiatives span the industry and are the drivers for incremental industry improvements. We hope to initiate future sessions, awards and challenges in sustainable development across the value chain at events and encourage input and ideas from the broader SME membership. References Azadi, M., Northey, S., Ali, S. and Edraki, M., 2020, Transparency on greenhouse gas emissions from mining to enable climate change mitigation, Perspective: Nature Geoscience, v 13, p. 100-104, doi.org/10.1038/s41561-020-0531-3 Baena, Ó.J.R., and Mendoza, L.E.M., 2021, Sustainability of the artisanal and small-scale gold mining in northeast Antioquia-Colombia, Sustainability v 13, 9345, 12 pp, https://doi.org/10.3390/su13169345 Canadian Mining Journal staff, 2020, Teck mine in Chile switches to renewable energy, Canadian Mining Journal, September 18 Nelsen, J., Scoble, and Ostry, A., 2010, Sustainable socioeconomic development in mining communities: Northcentral British Columbia perspectives, International Journal of Mining, Reclamation and Environment, 23 pp, doi.org/10.1080/17480930903185107 Olson Hoal, K., and Frenzel, M., 2022, Ores drive operations. Economic geology is the foundation of geometallurgy, SEG Discovery, Society of Economic Geologists, p. 30-43, doi.org/10.5382/Geo-and-Mining-15 Perdeli Demirkan, C., Smith, N.M, Duzgun, H.S., 2021. A Data-Driven Approach to Evaluation of Sustainability Reporting Practices in Extractive Industries, Sustainability, v 12, No.16: 8716, https://doi.org/10.3390/su13168716 The Eriez Hydro- Float has been used in mines at Rio Tinto, Newcrest and Anglo American. Early applications focused on recovering “lost” coarse metal units. Case study: Responsible mining and minerals processing by Eric Wasmund, Asa Weber and Jose Concha of Eriez There is now a global focus to reduce the emission of greenhouse gases and this has led societies, scientists, industries and governments to consider the specific ways to achieve this transition. A significant portion of this global rethink will be technological, and it will involve engineering, capital and materials. These technology platforms will include processes to reduce the carbon intensity of dominant industries such as cement and steelmaking, carbon capture and sequestration, green hydrogen and electrification. It is probable that all of these technologies, combined with energy conservation, will be part of the vaunted netzero economy. Each of these nascent technologies will require significant increases in the production of mined metals and materials. For example, a number of credible forecasts suggest that copper demand will increase from about 25 Mt/a (27.5 million stpy) today to 40 Mt/a (44 million stpy) by about 2030. Vale has recently forecast a 44 percent increase in nickel demand over the same period. There will be an even more dramatic increase for strategic minerals, including battery materials such as cobalt, graphite and lithium, and for rare earth metals used in electronics and motors. The availability of these materials are a prerequisite for the green economy, and the gap between demand and current supply cannot be made up by recycling alone while the green economy is in expansion mode. Many people in the mining world wonder where all of the new mines are going to come from in this future scenario, since these are all mined materials. There has been a steady decline in the head grade of new mines — copper head grades on average have declined from 0.7 to 0.5 percent over a couple of decades. As metal demand increases, one effect is to encourage the development of projects that were previously uneconomic because of low head grades. Lower head grades necessitate processing larger tonnages of mined ore to get the same amount of finished metal. Bulk mining is already a high tonnage enterprise, with some copper mines processing in excess of 300 kt/d (330,000 stpd) of ore; even higher earth moving is required when the strip ratio is considered. This will increase again because of these two related phenomena; higher output of metal and lower head grade. A 2021 study estimated that 3 percent of the electrical energy for global metals processing is used for comminution, and this will go up as metal production increases and cut-off grades decline. At the same time, mineral processing is wet, and lower head grades mean using more water to concentrate the same amount of metal. Many mining resources are located in regions with low water availability, such as the Atacama Desert, or they are in close proximity to other significant water consumers, such as those needed for agriculture and cities, so there is a greater importance on recycling water. To summarize, the green economy is going to create significant challenges for miners around energy and water use. Coarse particle flotation. Until recently, the basic flotation concentrator flowsheet has not changed much. Ore at or above the cut-off grade is identified by the mining operation, then it is crushed and ground to a suitable size to enable bulk froth flotation followed by an upgrading cleaner step to produce final concentrate for smelting and/or refining. For a typical porphyry copper ore, conventional flotation is not practical for particles above 200 microns, sometimes significantly less, so the endpoint of the grinding operation must be in this range, resulting in excessive grinding and serious challenges for water recovery, since dewatering becomes more difficult as the solids become finer. In a conventional plant, the usual way to address this is to thicken the tails and then pump to a water impoundment for settlement. In this scenario, a significant amount of water is lost to evaporation. Water losses means that the water in a concentrator cannot be operated in a closed loop and fresh water is always required. Other dewatering strategies exist, but they are energy and capital intensive. Coarse particle flotation is a key disruptive technology that has a major impact on water and energy, and it will be a key strategy to conserve both. By increasing the size where ore particles can be floated, typically 2 to 3 times, less grinding energy is required. And because the flotation tail is much coarser, it is easier to dewater, and has less retained water. Eriez introduced its HydroFloat Coarse Particle Flotation (CPF) equipment about 10 years ago with major base metal producers such as Rio Tinto, Newcrest and Anglo American. Early applications focused on recovering “lost” coarse metal units from conventional concentrator tailing streams. This typically represented at least 60 percent of coarse tails and a 2 to 6 percent global recovery improvement. Now the focus is on including the HydroFloat inside the mill circuit as an ore sorter. The first application of this type was successfully demonstrated at Anglo American’s El Soldado during 2021 and is now in full operation. This configuration of CPF allows a significant reduction in grinding energy and conventional flotation capacity, and it produces a coarse tail that can be easily dewatered or combined with conventional tails. As part of their FutureSmartMining family of technologies, Anglo American is piloting a technology to comingle coarse and conventional tails in unique ways to produce a waterless dry stacked tail. Two-stage flotation. Another Eriez technology that has been introduced to increase the efficiency of concentrators is the StackCell, a high-rate mechanical cell that uses the two-stage principle. In the first stage, high shear mixing of bubbles and feed slurry occurs to optimize bubble-particle collecting. In the second stage, which is isolated from the first, the bubble-particle aggregates can float by buoyant forces in a fluidic environment with low turbulence and a low energy convective flow that minimizes bubble particle detachment and drop back. The two-stage flotation technology contrasts with conventional mechanical tank cells where bubble-particle contacting and buoyant separation occur in the same fluidic environment, which cannot be simultaneously optimized for both processes. The StackCell is now operating in commercial rougher flotation applications in a number of countries. It has been verified that in many scenarios, StackCells can operate with one quarter or less of the residence time required for conventional technology, and with 40 percent less impeller energy. This all means smaller concentrators with less energy use.

Sustainable development across the minerals and metals value chain

Authored by:
Corby Anderson, Oscar Restropo Baena, Sebnem Duzgun, Steven Fecht, Karin Olson Hoal, Nicole M. Smith

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