With rare exceptions, water is key to minerals recovery. Meanwhile, mining is venturing further into already water-stressed areas of the world. E&MJ looks at some of the implications.
By Simon Walker, European Editor
Like the level in an unpumped sump, awareness of the importance of effective management of water resources has been rising inexorably across mining and mineral processing in recent years. That has not long been the case, however, and the fact that several of the regular conferences on mining-sector water management have only reached their third or fourth event shows that this is indeed a relatively new focus for the industry.
And the triggers for this new-found appreciation of a long-standing topic? Multi-fold, depending on which particular aspect of water management is under consideration. In terms of supply, the increasing reliance of Andean open-pit mines on desalinization plants has had a major influence. Rising social awareness in the same areas of Chile and Peru in particular has also played a major role, highlighting the need for fundamental consultation between groups that may well have widely divergent interests in water resources and usage.
In addition, the ever-increasing cost of treatment, both from existing and historical mines, before water can be discharged safely into the environment, has provided a spur for improved process technology and, critically, the development of new holistic perspectives on recycling as an integral part of water-sourcing.
In February, the International Council on Mining and Metals (ICMM) launched the latest in its series of publications that focus specifically on water-resource management for the industry. A Practical Guide to Catchment-Based Water Management for the Mining and Metals Industry sets out a collaborative approach to water management that considers the needs, concerns and priorities of other water users, and promotes inclusive and ongoing engagement with all stakeholders.
The publication sets out a comprehensive and systematic approach for identifying, evaluating and responding to water-related risks, and is structured as an interactive and informative prompt to guide companies in the development of their water strategies and plans in accordance with the local context and hydrology in which mining takes place.
The new guide builds on the advice contained in the ICMM’s Water Stewardship Framework, which was published in April 2014. This spells out the four principle tenets of the organization’s approach to achieving best practice in water management. Companies are urged to:
- be transparent and accountable;
- engage proactively and inclusively;
- adopt a catchment-based approach; and
- apply effective water-resource management.
Taking each of these in turn, the ICMM suggests that companies must publicly report material water risks, management activities and performance. In addition, the organization says, there is a need to engage stakeholders in an open and transparent manner to understand their priorities, share plans and collaborate on solutions.
Understand the social, cultural, economic and environmental value of water at the catchment scale to identify material water stewardship risks and provide context for corporate and operational water management, the CIMM advises. And in terms of resource management, companies should manage operational water inputs, use and outputs, in terms of both quantity and quality, to maximize resource sustainability, operational flexibility and economic benefit.
Water Pressure is Rising
In the foreword to a report published in 2013, the Carbon Disclosure Project (CDP) noted that “Fresh water scarcity is threatening the stability of the global economy. With greater competition, the world’s finite freshwater resources are a vital strategic concern for governments, investors and corporations.
“A cavalier approach toward water and taking its availability for granted is no longer an option,” the CDP went on. “Nowhere is this being felt more acutely than by the metals and mining sector—a sector under water pressure.”
Based in London, the CDP not only collates and publishes carbon-emission data on behalf of its institutional-investor and other backers, but also gathers water-related information in a move aimed at “catalyzing action on corporate water stewardship to safeguard water resources and address the global water crisis.”
The organization based its report on questionnaires sent to 57 publicly listed mining and metals companies as part of a much wider survey of corporate perceptions to water-related issues. From the 36 responses received, the CDP noted that almost all of these companies reported “exposure to substantive water risks that have the potential to impact their business now or within five years.” Looking beyond purely operational aspects, the CDP pointed out that “water poses a significant constraint to growth and threatens the future value of companies in the mining and metals sector.”
Not only that, but water challenges have already begun to impact the way in which mining companies run their businesses. The CDP report stated that financial impacts are already being felt, with “almost two-thirds of respondents having experienced detrimental water-related business impacts in the past five years. Corporations such as Anglo American, BHP Billiton and Rio Tinto report that they have already experienced significant water impacts that have led to changes in their company practices,” it pointed out.
“A total of 12 distinct categories of risk were identified by responding companies,” the report explained. “Increased water stress is the most commonly reported risk, which is consistent with the finding that one-third of respondents have the majority of their operations located in regions subject to water stress or scarcity.”
The CDP went on to sound a further warning: “It should also be noted that a quarter of respondents have not considered other risk indicators beyond water scarcity such as increasing regulation, inadequate infrastructure or community opposition,” the organization stated.
Current and Future Risks
Other areas of major immediate concern highlighted in companies’ responses included flooding and water quality, whereas regulatory issues were perceived more as a medium-term risk. Chief amongst these is tighter regulation of discharge water, with the CDP reporting Teck Resources’ response as saying that “more stringent discharge standards create operational challenges and may require temporary closure and production breaks.”
Changes to water-withdrawal rights and allocations is the regulatory risk most likely to impact now or within the next five years, the CDP survey revealed. “This is certainly a risk that would greatly impact metals and mining companies if changes are not anticipated,” the report stated, citing Barrick Gold’s response that any changes would, at least temporarily, “reduce production at operating mines, and limit the development of new mines or mine expansion.”
In terms of physical risk mitigation strategies, the increased use of water recycling seems to be favored, with Northam Platinum reporting that its closed-water circuit now recycles some 90% of its process needs on an annual basis. In terms of flooding prevention, fellow South African company Exxaro Resources noted that it regularly reassesses the run-off capacity of all its drainage and sumps to ensure containment in extreme flooding events, and it is looking at ways of determining its capacity to withstand a 1-in-100-year flood to prevent flooding-related work stoppages.
Looking at regulatory risk, Rio Tinto reported to the CDP survey that the company has: “created a water standard that requires all operations and new projects to develop and implement criteria on water abstraction, dewatering, effluent/discharge or water quality when government regulations are absent, insufficiently protective or ambiguous to ensure protection of surface water and ground water resources.”
With its background of researching for the investment community, the CDP did not shy away from pointing out the collateral implications of having a proactive mandate on water-resource management. “There are a number of companies,” it said, “including Anglo American, Exxaro Resources and Rio Tinto, taking a strategic, holistic approach to water governance, including engagement with communities in which they operate, proactive transparency and integrated water management informed by local water basin priorities. These companies are finding that being known as a company that does the right thing by stakeholders makes it easier to access new projects and raise capital.
“There are others, however, who have yet to move beyond basic legislative compliance.”
Does Water Quality Matter?
Writing in the October 2011 edition of specialist recruitment company Allen and York’s newsletter, marketing assistant Vicky Kenrick stated that water management is emerging as the pre-eminent sustainability issue within the global energy and mining industries. “With water being the most important resource in all mining and quarrying developments and operations, it can be used and abused. Hard-rock mines in particular use water in all steps of the mining process, from cooling equipment, separating waste from valuable minerals to controlling dust, and working with such large volumes of water presents a variety of risks.
“Steps towards a more sustainable mining industry should involve promotion of the use of low-grade water,” Kenrick went on, “usually saline underground or sea water, which agriculture and municipality do not want. This recovered water does not have to be high grade; in fact, many mining processes can tolerate high saline water. In addition, by encouraging water recycling as much as possible, companies can move towards a zero water discharge operation,” she pointed out.
Kenrick summarized the three areas of most concern in sustainable water management within the mining sector as:
- finding adequate sources of water to use;
- minimizing water consumption—by reusing wherever possible; and
- managing waste and remediating contamination.
In a recent interview with Mining IQ, Rio Tinto’s chief environment advisor for Africa, Sam Luoma, noted that the company established a formal water standard some 10 years ago. “More recently,” he went on, “Rio Tinto has increasingly recognized that dealing with water issues at many of its operations is a business imperative. Water scarcity, water excess, water access and extreme climatic events have the potential to limit production and growth, affect reputation, and affect the company’s social license to operate in crucial locations,” he added.
The company’s water strategy sets high-level goals and objectives for dealing with water issues, committing it to responsible water stewardship across the group, Luoma explained. The strategy defines three goals:
- improving water performance;
- accounting for the value of water; and
- engaging on water issues.
It also provides a framework for local water strategies, he said, with the company having developed a group water target as a part of the strategy, to assess progress in meeting its goal of continuously improving water performance.
“Many mining companies have water-management plans,” Luoma stated, “but explicit water-balance models are less common, especially those that include consideration of catchment dynamics in the long or short term. Water issues are sometimes overlooked in community, nongovernmental organization (NGO) and government engagement. All stakeholders need to be identified—the social aspects of water needs have often been overlooked in the past.”
Water in a Social Context
Although there have been some notable instances where water resources have formed the focus for disputes between mining and community interests in arid areas, that is by no means the complete picture. Nor is it necessarily the case that water resource management is exclusively an issue for the hard-rock mining industry: the potential impact of coal mining-induced subsidence on local water supplies is also something that requires careful mitigation.
In May 2014, the International Finance Corp. (IFC) published a discussion paper entitled Water, Mining And Communities: Creating Shared Value through Sustainable Water Management. The foreword cited research by Morgan Stanley, which shows that while mining uses 5% of water globally, “the industry often receives the majority of the blame for negative impacts, even when other sectors are drawing on and impacting this resource.
“For example, in Peru, mining consumes 1.46% of water used but receives the most criticism for poor management. Such criticism is based on both fact and perception, and is increasingly impacting business and community-government relationships.
“For the mining industry, water management is more than just a technical and economic challenge,” the paper pointed out, citing figures from the World Bank showing that over two-thirds of the mining-related complaints referred to its Compliance Advisor Ombudsman since 2000 have included water issues. “The social and environmental dimensions of water have a profound impact on the cost of developing new projects, expanding existing ones, and most recently, closing old mines,” it stated.
The paper’s view was that it has often been the case that social factors related to water have been given insufficient attention early in the planning and operations stages, when stakeholders are less active and critical engineering choices are made—although this is changing. Nonetheless, failure to earn social license—a community’s tacit approval of a project—is one of the greatest risks facing mining companies, with several having had projects shut down because of community-led protests, many sparked by concerns over water. According to the IFC, it continues to see technically sound investment projects face complaints or closures because of water-related issues.
Water can be a lightning-rod for conflict, the IFC stated, with triggers for disputes including water scarcity, lack of access, unclear rights, water excess, impacts on water quality, unequal voice, and a general lack of trust. “There is a growing list of companies whose experience with water and conflict indicate that it is more expensive to recover from conflict than to prevent it. Broken trust takes longer to repair than a concentrator or pipeline,” the IFC advised.
Management in Practice
In 2012, the ICMM published a report on water management in mining, based on a set of case studies. “Laws regulating water vary around the world, but it is fair to say that the mining sector can expect to be increasingly required to demonstrate a leadership approach to water use and management,” the report’s authors commented.
Identifying suitable water sources is key to building a successful mine, whether the water comes from the mine itself, through pumping, from local surface sources such as rivers or lakes, or from distant underground aquifers. Water that may be problematic at the mining stage may, of course, be an essential input when it comes to mineral recovery.
On the other hand, water that is surplus to day-to-day needs requires disposal, as does process effluent, and this in turn can incur the need for significant investment in cleaning and treatment before discharge. Nonetheless, careful planning and a perspective that stretches beyond the mine fence can lead to a win-win situation for both the operation and the surrounding community, as the ICMM case study on Freeport-McMoRan’s Cerro Verde mine in Peru demonstrates.
With fresh water resources in the Arequipa district being scarce, the city population growing, and plans in hand to triple output at Cerro Verde, Freeport has built new potable water and wastewater-treatment plants to serve the city. From its perspective, the company wins because the treated output from the wastewater plant is used in the expanded concentrator, while the citizens of Arequipa and the surrounding district win with new fresh water supplies and less pollution in the Rio Chili.
According to Freeport, planning, constructing and commissioning these plants has cost over $90 million. In addition, Cerro Verde operates a zero-discharge policy, with 85%–90% of its process water needs being recycled.
Another operation cited in the CIMM report, Areva’s now mothballed Trekkopje uranium mine in Namibia, also provides nearby communities with water from its facilities. To secure water needed for its leaching process, the company built a 20-Mm3/y seawater desalinization plant on the coast, connected to the mine by a 50-km-long pipeline. However, process re-engineering resulted in the mine cutting its make-up water requirements from the initial estimate of 20 Mm3/y to 14 Mm3/y, leaving sufficient capacity to meet nearly half the water needs of the Erongo region—industrial and domestic. In addition, the national water utility will take over the desalinization plant when Trekkopje eventually closes.
In all, the CIMM report covers 10 case studies, some of which focus on aspects of water management other than ensuring adequate supply. For instance, Rio Tinto described the work undertaken at its Argyle diamond mine in Australia to reduce its water demand from Lake Argyle by 95% in five years, while at the same time improving its water recycling rate. Two further studies addressed the management of post-mining contamination, from Barrick’s Homestake mine in South Dakota and from JX Nippon Mining and Metals’ Toyoha mine on the island of Hokkaido, Japan.
Build for New Extremes
For whatever reason, world weather patterns are changing, and this has to be factored into mines’ water-management planning. At existing mines, formerly reliable water sources may begin to lose capacity, while existing systems for handling run-off events may prove to be less capable of doing so as storms become more intense.
Conversely, lower rainfall within a mine’s catchment area may increase the need for alternative supplies, or a rethink on how water of varying qualities can be best put to use. For example at Olympic Dam, BHP Billiton is now used hyper-saline ground water for road dust suppression and vehicle wheel-washing, saving higher-quality water for use in the process plants. The specific aim here has been to reduce the mine’s impact on the water resources of the Great Artesian Basin, on which other users and natural wildlife are reliant.
Writing in a brief review of the 2015 Mine Water Solutions in Extreme Environments conference, held in Vancouver in April, co-chairmen Pat Corser and Dirk Van Zyl noted that: “climate variability is real and is going to have to be part of our project evaluations, in particular in the evaluation of mine closure plans.
“The greatest challenges in managing mine waters arise at mines in extreme environments,” they went on, before pointing out that it is not just mines in arid environments that have water-management challenges. So may mines in areas of high rainfall, and those where extreme cold—either seasonally or all year—is the norm. Looking at the flip side of the coin, “there are credible estimates indicating temperatures will be increasing in northern Canada in the coming years,” they added, “so we must fully recognize the impacts that rising temperatures will have on engineered facilities.”
Last September, the ICMM organized an expert panel as part of the annual World Water Week conference, held in Stockholm. “A catchment-based approach to water stewardship is about a paradigm shift, looking outside of the operational fence to your impacts downstream,” said Stuart Orr, head of water stewardship at WWF International. “It requires skills and capacity, investment and commitment. This requires mining companies to work with other mining companies, other industries, government, communities and NGOs to address these issues.”
Andrew Parsons, vice-president for sustainability and environment at AngloGold Ashanti agreed. “As an industry, we need to look further downstream, beyond immediate production issues to the needs of the wider catchment,” he said.
“Water is one of the most significant issues facing the mining and metals industry and society at large,” said Ross Hamilton, director of environment and climate change at ICMM. “Effective water stewardship requires an approach based on finding solutions that work for business and all other water users.”