Mine Water Management: No Simple Recipe

Mining must become more adept at finding acceptable water-source solutions in an increasingly complex, thirsty world

By Russell A. Carter, Managing Editor

Water and gasoline generally don’t get along well together, but these two commodities have more in common than many people realize. When used in large volume, both must be managed carefully to control costs and ensure adequate supply. In the future, demand for both is expected to grow dramatically, driven by expanding population levels and lifestyle expectations from new middle-class consumers in rapidly developing countries. Consequently, both are also expected to become more expensive, inflated by heightened demand and limited supply. And, both have incendiary properties that can be useful or destructive: Gasoline is volatile, yet necessary to power much of the world’s vehicular motion; while water—or more often, lack of it—has the ability to inflame civil unrest that can halt an industrial or mining project in its tracks.

Although the gasoline/water analogy falters a bit when applied to mining—which mostly runs on diesel fuel—experts predict that water issues will generate a lot of heat for the global mining industry in the coming years.

Perhaps the most vivid recent example of water’s ability to incinerate carefully laid plans is the controversy surrounding the $4.8-billion Conga gold/copper project in Peru, a property held by Minera Yanacocha S.R.L., in which Newmont Mining owns a 51.35% interest. Conga is an important element for Newmont, which concedes that failure of the open-pit mining project to advance to production could have an adverse effect on its future growth if it were unable to replace Conga’s anticipated output, which is in the range of 600,000–700,000 oz/y of gold and 160,000–240,000 lb/y of copper. But Conga, located 24 km away from the joint venture (Newmont/Buenaventura) Yanacocha gold mine, has been the target of local political and community ire, leading to suspension of construction activities at the Conga site in late 2011 at the request of Peru’s central government following increasing protests by anti-mining activists led by the regional president. At the core of the controversy are concerns about water. The initial plan called for draining of four high mountain lakes, with one to be used as a slag pit. Opponents claim the project would harm the water supply, both in quantity and quality. Protests led the government to seek an independent assessment of the project’s environmental impact study, leading to recommendations that two of the lakes be left intact and that water storage capacity of the reservoirs be increased. However, the local opposition is convinced that the water supply will be adversely affected even with that revised approach.

In the wake of the protests and mine-construction shutdown, Minera Yanacocha has adopted a “water first” philosophy that is focused on building water reservoirs prior to the development of other project facilities. Newmont said the project’s plans for 2013 call for spending about $150 million in capital expenses, including approximately $110 million on equipment, owners’ costs and engineering support; $20 million to complete reservoir construction; and another $20 million or so for community costs, roads and water systems. However, Newmont also warned that development of Conga is contingent upon generating acceptable project returns and getting local community and government support. Should it be unable to continue with the current development plan at Conga, Newmont said it “may in the future reprioritize and reallocate capital to development alternatives in Nevada, Australia, Ghana and Indonesia, which may result in an impairment of the Conga project.”

Fighting the Battles
Newmont also has conducted a running battle of words against what it sees as misleading or incomplete accounts of the project and its approach to water management in the world press (see below). And, looking beyond the Conga conflict, it’s quite clear that industry adversaries will continue their efforts to increase pressure on public-land stewards to suspend or curtail mining projects in other areas of the world as well, based on water concerns.

For example, a report released on May 1 by Earthworks—a Washington, D.C.-based nonprofit organization that describes itself as “dedicated to protecting communities and the environment from the impacts of irresponsible mineral and energy development while seeking sustainable solutions”—claims that existing U.S. hard rock mines will pollute up to 27 billion gallons of fresh water per year, and cost as much as $67 billion per year to clean, in perpetuity. The study, titled Polluting the Future: How mining companies are polluting our nation’s waters in perpetuity, also claims that four proposed new mines could annually pollute billions of gallons more.

The study lays blame on acid rock drainage (ARD), which can occur when sulphide-bearing materials are excavated, exposed to air and water, and then react with oxygen and water to create sulphuric acid. The press release accompanying the release of the Earthworks study quoted Dr. Glenn Miller, a professor of environmental science at the University of Nevada—”No hard rock open pit mines exist today that can demonstrate that acid mine drainage can be stopped once it occurs on a large scale”—and went on to state that “because acid mine drainage can’t be stopped, once started it must be treated until the acid generating material runs out. As acknowledged in government mine permitting documents, this can take hundreds or thousands of years.”

In addition to listing existing U.S. mines that “are known to generate perpetual water pollution,” the study also identifies what it terms “existing mines likely to generate perpetual water pollution,” as well as four proposed mines at which it says perpetual water pollution is predicted or considered at high risk (see table, p. 44). These mines, according to the study, could generate an estimated 16 billion gallons of contaminated water per year. The 52-page report, downloadable at http://www.earthworksaction.org/files/publications/PollutingTheFuture-FINAL.pdf, makes several policy recommendations:

• The U.S. Environmental Protection Agency (EPA) should use Section 404c of the Clean Water Act to protect Alaska’s Bristol Bay, which it identifies as “the nation’s most productive and valuable wild salmon fishery,” facing possible degradation from development of the proposed Pebble mine.
• Reform federal law to require hardrock mines to demonstrate, at the outset, that the mine can meet water quality standards without perpetual treatment.
• Reduce perceived risk by restoring federal regulations to prohibit mine waste disposal in waters of the U.S.
• Hold corporations accountable by putting the cost of AMD cleanup on the industry, not on taxpayers.

Proposed Mines Predicted to Generate Perpetual Pollution, or at High Risk of Perpetual Pollution
Mine	Location	Annual volume of water requiring treatment	Annual treatment costs (operating and maintenance)	Status	Land ownership	Resource at risk
Donlin Creek (Donlin Gold)	Alaska	Estimated: 1.7 billion gallons	Estimated: $1.9 million	Proposed	Native corporation	Kuskokwim River Watershed
Pebble (Pebble Partnership)	Alaska	Potential, estimated 13.8	Unknown	Proposed	State of Alaska	Bristol Bay salmon fishery
Northmet Project (Polymet Mining)	Minnesota	Potential, estimated: 83 million to 256 million gallons	Unknown	Proposed	National Forest	St. Louis River Basin, aquatic organisms, wildlife, wild rice, wetlands, groundwater
Rock Creek (Revitt [sic] Silver)	Montana	Estimated: 1.2 billion gallons	Estimated: $1.2 million	Proposed	Forest Service	Clark Fork River
Source: “Polluting the Future: How mining companies are contaminating our nation’s waters in perpetuity,” Earthworks, May 2013.

 

Looking at the Problem
The foreword to the International Council on Mining and Metals’ (ICMM) 2012 report titled Water Management in Mining: A Selection of Case Studies, spells out, in broad terms, the future of the global mining industry and its relationship to water management: “In mining, water is used within a broad range of activities including mineral processing, dust suppression, slurry transport and employee requirements. Over the last several decades, the industry has made much progress in developing closed-circuit approaches that maximize water conservation. At the same time, operations are often located in areas where there are not only significant competing municipal, agricultural and industrial demands, but also very different perspectives on the role of water culturally and spiritually.

“Together, these characteristics lead to tough challenges and there is no simple recipe for water management in mining, particularly because the local environments of mines range from extremely low to the highest rainfall areas in the world. Regardless, responsible management of water by mining companies is a key ingredient in ensuring their contribution to sustainable development is positive over the long term.”

Left unsaid is the fact that responsible management of water by mining companies also is a key ingredient in profitable production: flooded pits can’t be mined, processing effectiveness can be reduced by poor-quality water, and sloppy heap leach operations may draw regulatory fines that could affect bottom lines, for example. Savvy mine operators understand the dual nature of water’s value. It can be an asset or a liability, depending on its location and use: water residing within a managed system can generally be regarded as an asset or resource; while water leaving the system can often be considered a liability.

In the U.S., Nevada is the driest state of all, averaging less than 10 in. (250 mm) of rain per year. It is also regarded as probably the most extensively mineralized state based on current geological information, containing in addition to its gold and silver deposits other commodities such as copper, lithium, vanadium, molybdenum, tungsten, niobium and 17 rare earth minerals, among others.

With its robust mining industry, rapidly expanding population centers, and competition for scarce water supplies by industry, agriculture and municipalities, Nevada could serve as a bellwether for the global industry in recognizing and, hopefully, finding ways to resolve water management issues in resource-limited regions. The annual meeting of the Nevada Water Resources Association, held January 29-31 in Reno, confirmed the state’s mine operators are cognizant of the challenges and are actively seeking solutions to slake the industry’s thirst.

Allan Biaggi, former director of Nevada’s Department of Conservation and Natural Resources and administrator of the Nevada Division of Environmental Protection, listed a number of the challenges facing the industry in his presentation at the NWRA event.

• Water is not going to be any less scarce or less precious;
• New and existing uses of water will compete with mining for Nevada’s water resources;
• The cost and value of water will increase;
• Water will become more politicized;
• Mineral extraction/production will increase and concurrently water demand will increase;
• Litigation over water issues will increase;
• Public land managers will have a greater say over water within their jurisdictions;
• The environmental impacts of mine dewatering will continue to be of concern;
• Post mining features such as pit lakes will face increased scrutiny and focus; and
• Bonding and other financial assurances will play a greater role in the long-term protection of water resources.

Given these prospects, there are specific steps that can be taken to accommodate them and ensure the health of the state’s mining industry in the coming decades, Biaggi noted, and suggested a few, including:

• State water policy must be adaptable and capable of responding to changing demands, economics and technologies for all users.
• Mining should undertake an effort of long-term water planning in conjunction with other users. The goal: optimize water use and consumption.
• Mining will continue to pursue the reuse and recycling of process waters.
• When possible, low-quality water should be used for mining production.
• Mining will develop technologies to reduce volumes of water extracted as mines go deeper.
• Mining will continue to innovate on the reinjection/restoration of dewatered aquifers.
• Federal and state agencies must ensure consistent, fair and predictable water allocation requirements and permitting processes.
• Renewed policy direction to recognize mining as being valuable to Nevada.

Taking Steps
If the importance of water management in the long list of a mine’s typical economic and regulatory issues is accepted, then how is it defined? According to Matthew Setty, senior project manager and global mining client manager for engineering firm CH2M HILL, it comprises “the sourcing, conveyance, diversion, storage, reuse, treatment, and/or disposal of all water associated with the mine and mill operation, regardless of use, and adapting to flow and quality changes both seasonally and throughout the mine life cycle.”

It’s an important part of any sustainability program, said Setty, noting that a company’s mine water management must be structured to deal with the harsh realities of today’s operating environment; i.e.:

• “No water, no mine.”
• Lower grade ores increase water consumption.
• Climate change and population growth are increasing competition for water.
• Water and environmental issues must be addressed to obtain or maintain a social license to operate.

Setty said close attention to water management will be necessary to comply with increasingly stringent water-discharge requirements coming from a variety of regulatory sources, such as conductivity limits proposed by the U.S. EPA, new water quality criteria (e.g., selenium, sulfate, nitrates) proposed by the EPA and Canadian authorities, and whole effluent toxicity (WET) requirements from both the EPA and Canadian agencies.

Water issues change at each stage of the mining life cycle, and the water management plan must adapt accordingly, he explained, and starting out with a comprehensive plan is necessary for success. A plan would typically involve:

• An accounting of all water inputs and outputs and changes in storage.
• Attention to evaporation and transpiration factors.
• Initial development as part of the Environmental Impact Assessment.
• Realization that corporate reporting of company-wide water balance is becoming more common.

The plan would ideally be subject to ongoing refinement and redefinition, and used throughout the life cycle of the mine.

Marek Mierzejewski, CH2M HILL’s Water in Mining sector lead and co-presenter with Setty of the NWRA paper, wrote in the company’s Access Water blog last year said, “As sustainability and environmental concerns have escalated, the mining industry faces increasing public, media, and regulatory scrutiny regarding how it sources, treats, and manages water. To comply with more stringent regulations and maximize efficiency, mining companies now face the need for greater technological and strategic approaches to water maintenance, treatment and reuse. Concerns of how water is used, recycled, waste is disposed of and residuals are managed, are boardroom issues for mining companies these days.

“So water, once considered a readily available and manageable resource, is now a major business concern, and frequently a deciding factor as to whether or not a mine is developed. This is particularly challenging as mining often takes place in arid and semi-arid regions, like Chile and Peru, where water is a limiting factor for the development and continuation of mining operations. Many of the papers and presentations at [a recent] conference provided solid data on the benefits of desalination in these areas to increase water supply—important because a remarkable 40% of global mining projects over the next five years will be located in Chile and Peru.”

Mierzejewsk, along with four other staffers at CH2M HILL, authored a report in 2012 that examined the changing value of water in five industrial sectors: semiconductor manufacturing, thermal power generation, mining, chemicals, and oil and gas. The mining section focuses on the approach taken by two mining divisions within Rio Tinto to adopt water management strategies.

The examples presented in the paper illustrate what seems to be an emerging willingness among major mining companies to step outside the confines of their various operations, look around and engage with organizations, regulators, other stakeholders and even competing companies to identify and resolve water-related concerns. It’s a strategy endorsed by a growing number of mining advisory groups; the ICMM report referenced above, for example, states that “engagement with stakeholders is essential tor each consensus and agreement on the many water issues that affect the mining sector and the communities in which it operates.

“The industry’s engagement needs to be undertaken at global, regional and operational levels, to ensure that it is a constructive voice in the emerging policy debate,” it concludes.