Designing Mines with Water in Mind

Climate change, a growing global population and accelerating urbanization are deepening concern over the world’s water security. From floods to droughts, too much water to not enough, there doesn’t seem to be an end in sight for the world’s continuing water woes.

As a result, the environmental, social and economic costs of water are narrowing the focus on how mining companies use and manage water. Under increased pressure from shareholders and regulators, mining operations companies are building business cases based on the triple bottom line of environmental, social and economic concerns. Mismanaging water can have serious consequences, not only on operational costs, but on the mine’s reputation and social license to operate.

Peering into the future, water management will only play an increasingly critical role as mining companies increasingly focus onto designing mines with safety and sustainability and efficiency as core considerations. This will involve developing comprehensive programs to ensure the ongoing sustainable management of water, throughout the entire life cycle of the mine. And this effort is not a task reserved for new mines; rather, the lens of sustainability is now being applied to all mines – new and operating – to maximize productivity, efficiency and resilience.

The Promise of Advanced Technology

With the proliferation of connected devices, smart infrastructure and data analytic capabilities, today’s mining operations are well-positioned to benefit from advanced new technologies that can offer safer, smarter, more sustainable long-term solutions.

Within the realm of water management, we’re seeing automation, sensor technology and control devices offer heightened levels of systems intelligence. For example, a system of sensors can provide real time insight into a mine’s water use by using water management simulation to identify inefficient water circuits, potential problems and minimize wastage and leaks. This critical information can help a mine to improve water use efficiency.

The concept is not new. Recognizing the benefit of these systems, the U.S. water utility industry has invested heavily in remote monitoring and automation as they work to deliver more efficient service and reduce non-revenue water. Mining companies that follow a similar pattern – actively embrace, invest and integrate smart infrastructure into their operations – will be in better shape to optimize efficiency and meet water use targets and sustainability goals.

Opportunities in Water Treatment

Recognizing the potential, and indeed the importance of increasing use of recycled water, many mines are actively working to increase their use of “fit-for-purpose” water. By treating water to appropriate levels, mines can select and use the lowest-quality water possible for certain operational requirements. Relying on treated, lower-quality, lower-cost water can reduce the need for imported fresh water, saving significant expense and reducing the impact on a local water supply. To integrate fit-for-purpose water, mining companies should identify areas of the mine where the lowest quality water can be used and match this need with an appropriate treatment regime.

Several advances in water treatment technologies are equally encouraging. For example, desalination can be a cost-effective solution in certain areas and geographies. Current desalination processes rely on reverse osmosis, which involves pumping water through semi-permeable membranes. Although effective, this technology is somewhat limited, as it involves large amounts of energy and results in a left-over brine that must be managed.

But we are seeing increased movement in new desalination technologies, from testing new types of membranes to investigating vaporization methods. Two new approaches (concentrated solar stills and closed-circuit desalination) may offer new solutions.

A U.S.-based desalination project – the Brackish Groundwater Desalination program in San Antonio, Texas – stands out as an example of innovation in desalination. The San Antonio Water System (SAWS) project was developed to supplement and diversify the city’s water resources portfolio in an area that struggles with drought. Black & Veatch was retained by SAWS as the program manager, and the company’s role included pre-design, design, construction and commissioning.

The reverse osmosis treatment facility incorporates some innovative concepts in its design, including the use of energy recovery devices to transfer hydraulic energy from the concentrate stream to the feed stream. The facility also includes a reverse osmosis testing unit to demonstrate the performance of specific types of membranes and conduct optimization studies. The program delivers up to 12 million gallons of drinking water each day.

Chile’s Escondida Water Supply (EWS) project is another example of innovation in large-scale desalination. The world’s largest copper mine, Escondida is located deep in the Atacama Desert. To improve water supply reliability while preserving the local community’s freshwater, the mine’s majority owner and operator, BHP Billiton (BHP), built the largest desalination facility in the Americas to carry demineralized water more than 160km (100 miles) from the ocean to the mine at an elevation of approximately 3,000 meters (10,000 feet).

The project involved a technologically advanced desalination plant, conveyance system and supporting infrastructure; today, the EWS project delivers 2,500 litres of water per second (57 million gallons a day) to the mine. BHP contracted Black & Veatch to lead the engineering, design, procurement, field inspection and pre-commissioning for the marine and desalination components of the EWS project. The project won the Industrial Desalination Plant of the Year honour at the 2017 Global Water Summit.

The Future is Water Management

The mining industry’s approach to water management – which is like many programs focusing on energy and power use – is slowly evolving from traditional reactive approaches to more proactive, holistic measures that consider systems data, heightened levels of situational awareness and the Industrial Internet of Things (IIoT). To this point, creativity and innovation will play a critical role in helping mining leaders develop practical and cost-effective water practices.

Today, mining companies have a wide array of options when it comes to driving towards a goal of “net zero” water usage. To reduce risk and enhance resilience, mining operations should actively consider building water management portfolios that combine traditional options such as recycling and reuse with more advanced approaches, from use of advanced data analytics to treatment methods and desalination. In addition, companies should consider diversifying their water supply and investing in new treatment practices to enhance resilience, reduce and mitigate their impact on water resources, such as increasing fit-for-purpose usage.

Mining companies would also be well served to involve the local community as much as possible, and to work to understand and meet their needs. Partnerships will play a critical role and companies should consider building relationships – not only with the local community, but with other miners, industries and regulators in their region. This sense of collaboration will help generate sustainability benefits and improve cooperation amongst all major players, providing greater opportunity for mutually beneficial outcomes.