MINE WATER
A water-driven approach
Mining in South Africa has faced a significant downturn in recent years. Focusing on water efficiency may help secure savings for mines while also preserving a limited resource. By Danielle Petterson
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outh Africa, although technically a water-scarce country, is fortunate to have sufficient water resources available to support large-scale mining operations. However, the relatively wide availability of water may have led to complacency around the use of water in mining operations, says Stephen Rose, director advisory group: Industry, Royal HaskoningDHV. “Optimising your water efficiency has a direct impact on optimising the performance of your mine. When we are undertaking feasibility or economic assessments for mines, we often find that water is a key deciding factor in determining whether the mine will be viable or not,” he says. This is fundamentally linked to the availability of water on the mine site and the cost of importing water. Mines use a vast amount of water in their operations. On average, in South Africa, coal mines use 0.8 m3 water per run of
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mine (RoM) tonne, gold mines use 2.5 m3 per RoM tonne, and platinum 1.7 m3 per RoM tonne. However, a massive disparity exists in water use at different mining operations. “There is data to indicate that certain mines are doing far better at water conservation and reuse than others. On some gold mines, water use drops to as low as 1.1 m3 per RoM tonne. On mines that don’t perform as well, it goes up to 3.5 m3 per RoM tonne,” says Rose. While some mines are performing better than others, current legislation – which Rose describes as prescriptive and forwardlooking – enforces compliance in many areas. However, enforcement of the law can be a challenge.
Water efficiency
“Mining is extremely water intensive and it is absolutely critical that the mine’s operations are geared up to be as efficient as possible to minimise the use of fresh
water. We should adopt a water-driven mining approach with water-sensitive practices at the core of mining,” says Sheilla de Carvalho, director business unit: Industry & Smart Asset Management, Royal HaskoningDHV. When it comes to optimising water usage to make a more profitable mine, there are two metrics to focus on: consumptive water use and total water use throughout operations. Optimising your water use per tonne not only increases the chances of having your water-use licence application approved but also creates a more sustainable business. “The less water you use, the less you have to pump, the less you pay in electricity charges, the smaller equipment you will require and, consequently, the less your maintenance costs are likely to be,” explains Rose. Many mines in South Africa are waterpositive – meaning they generate more water than they use. When discharging into the environment, water must be
