Mine operators are looking to technology to solve a rising demand for water resulting from changing regulations or in areas of water scarcity. Xylem director of sales and services Ken Albaugh details the quandaries and solutions.
As the global economy grows hungry for the raw materials that help power electric vehicles, wind turbines, solar panels and other technologies, the mining industry is scaling up operations. The market for minerals key to the clean energy transition has doubled in size over the past five years, according to research by the International Energy Agency.1
Water is a critical, often overlooked element of the mining process. Bluefield Research identifies the mining sector as the world’s second most water-intensive industry.2
To meet growing demand against a backdrop of water scarcity and tightening regulations, mine operators are turning to technology.
A recent report by Bluefield Research found that globally, the market for water management, including CAPEX and OPEX for mining, is forecasted to reach US$9.24 billion in 2023. Water management spending is expected to increase at a 3.1% compound annual growth rate (CAGR) over this decade. 3
This is a moment to rethink water management – and many mine operators are leaning in. Innovative companies are embracing technology across every step of the mine water cycle, to meet production demands, reduce costs and turn mine water management from an expense to a strategic advantage. The challenge for the mining industry is clear: meet growing demand for materials and manage water more efficiently and sustainably.
Mine operations rarely fit a mold, with each having its own set of challenges determined by what is being mined and the local geography, among other factors. As such, mine operators require diverse, flexible technologies to support effective water management.
Earlier this year, Xylem and Evoqua came together to create the world’s most advanced platform to address critical water challenges in mining and beyond. With this expanded platform, our mission continues to focus on helping mine operators rethink how they manage water to deliver better business and environmental outcomes.
Evoqua and Xylem experts have built up over a century of experience on mine sites deploying technology and services, that solve dewatering, source water, wastewater treatment, environmental monitoring and contaminant removal, and mitigation of tailings in ponds and more for mine operators. These capabilities help miners efficiently manage water, improve environmental outcomes, and keep local towns and villages safe from contaminants.
Membrane separation technology can be combined with biological treatment to help companies meet compliance demands, particularly around removing elements difficult to treat, such as selenium – a naturally occurring element in some rock formations, especially around coal seams.
A perfect example of this is in Idaho, where mine runoff is treated to prevent selenium from reaching the Salt River. By integrating membrane technology upstream of Evoqua’s SeHAWK bioreactor, the mine was able to meet contaminant removal requirements and achieve higher treatment flows, thereby protecting the Salt River’s water and aquatic ecosystem.
Operators are not just using water efficiently, but also reusing it with the potential to do a lot more with an untapped resource – only about 54% of mine water is currently recycled.4
Take the approach of the Freeport-McMoRan Morenci mine in Arizona, the largest copper mine in North America. The mine owns, maintains, and operates the wastewater treatment plant for the cities of Morenci and Clifton, Ariz., and the site itself.
As the population of Morenci and Clifton grew, the wastewater treatment plant was challenged to handle the treatment flow. At the same time, the copper mine needed to expand the operation onto and beyond the existing treatment plant site. This development would require establishing a new site for the facility with a treatment design of 347 gallons per minute (gpm).
The initial timeframe of over one year was reduced by five months. The Evoqua project team partnered closely with the mine to stay on target. The new design included an activated sludge biological nutrient removal (BNR) process in a field-erected treatment plant system.
The plant and copper mine are now at zero discharge. Wastewater treatment plant effluent is discharged to the copper mine’s tailings holding reservoir, which collects and holds the copper mine’s process and runoff water. This water is then processed and reused in the copper mine.
A tailored, custom approach is vital to help clients achieve better outcomes, such as when source water is at a premium, putting the onus on operators to reduce water waste and minimize downtime. By taking a custom approach, mine operators, along with their service solutions partner, can examine their equipment and determine whether pumps are operating at their best efficiency point or whether are they working in a way that leads to premature wear and higher energy consumption.
Delta Sand & Gravel Co. in Eugene, Ore., is a case in point. A quality aggregate materials, service and expertise provider with a legacy of nine decades, the company had plans to increase the depth of its aggregate pit by 100 feet.
The aggregates mine features a central collection pit that handles all surface water from across its operations. Surface water is pumped to a series of five settling ponds before being safely discharged into the environment or re-used on site.
Already in place for several years, the three permanently installed pumps were inefficient and experienced frequent maintenance issues. The in-rush current at start-up was also problematic, adding maintenance costs and risking surges that could impact the surrounding power grid.
By upgrading to a highly efficient system, at the center of which is Xylem’s Goulds Water Technology vertical turbine pumps with variable frequency drives (VFDs), it now consumes 25% less energy. Due to the flexibility of the pump model, the upgrades will continue to operate at best efficiency point, giving operators peace of mind that the pump can be configured for optimal efficiency even as they lower the pit.
For other operators, a strategic approach to the treatment of mine water can have a positive impact, for instance with membrane separation technology that can help companies meet compliance demands, particularly around removing selenium – a naturally occurring element in some rock formations, especially around coal seams.
Mines are embracing technology to optimize their operations, reduce their impact on the planet, and meet regulations. By taking a strategic view of water and embracing innovative approaches, they are turning systemic challenges into competitive opportunities.
About the author: Ken Albaugh is director of sales and services at Xylem. He is a MSHA-trained and certified miner who has spent the last 20 years leading major mine dewatering projects for a wide range of mining customers and contractors.