The Usage and Treatment of Water in the Mining Industry
Few industries have more potential to damage the environment than mineral exploitation. Many of the processes essential to this industry employ and subsequently contaminate vast quantities of water. Unless suitably treated, the effluent from mines can have severe consequences if allowed to seep into streams, rivers or underground aquifers. Therefore, effective mining water treatment is just as vital to our modern society as the various mineral ores responsible for its contamination.
The average mine will utilise approximately 250 litres of fresh water for each metric ton of coal it produces. However, this figure represents only around 25 per cent of total usage. In a well-run operation, the remaining 75 per cent of the mine’s requirements will be obtained by recycling.
Why Do Mines Utilise so much Water?
Underground operations carry a high risk of fire and explosion, so the liquid is essential for cooling cutting surfaces that might otherwise create sparks. Whether fresh or obtained by mining water treatment, it also provides an effective means to dampen the highly combustible coal dust and maintain a breathable, dust-free atmosphere for the mineworkers.
After crushing and grinding, the coal must then undergo additional processing. By mixing the crushed and ground material with water to form a slurry, it is possible to transport it via a pipeline. Pipeline transport is cost-effective and ensures a continuous feed to the processing plant.
Operating an effective means of mining water treatment is a legal requirement regardless of the material mined and has two essential benefits. It reduces a mine’s total consumption and ensures any effluent that may be released into the area surrounding the mine will not pose a threat to local communities or ecosystems.
The Clean-up Process
Whether it is the product of an industrial process or stormwater and drainage, the primary objective must be to remove any metals or other potentially toxic materials present and adjust the pH using an appropriate mining water treatment programme. The process requires several stages and begins by introducing hydroxyl ions into the acidic effluent to raise its pH to around eight and form a precipitate of insoluble metal salts.
Adding coagulants and flocculants can increase the efficiency of the next stage, which is mechanical filtration. In addition, other additives, such as anti-corrosion chemicals, water softeners and disinfectants, may also be introduced, especially if the treated product is destined for reuse in the mine.
Because mining water treatment is crucial, effective technology and equipment are a fundamental requirement. Regardless of your industry, you can rely on Watericon for world-class wastewater recycling and purification equipment and expert advice regarding its selection and operation.