Mining and mineral processing operations can have a negative impact on the surrounding environment. Mining is dependent on water sources for drilling, excavation and product flow. While often undertaken in remote regions, mining can create water quality issues for underground aquifers from which residents get their drinking water. Large water volumes required for both surface and underground mining are dependent on reuse in order to maintain production and preserve scarce resources.
Mining wastewater contains residue from the ores being mined including heavy metals, cyanide and a high percentage of other related solids. If not addressed properly, toxic tailings can build up and leach into surface water supplies. Suspended solids are common in virtually all mining types. These solids can be fine ore or coal materials or silt from surrounding terrain. These suspended solids can influence the degree of turbidity. Depending on the material mined, effluent can be alkaline, acidic, and can contain chlorides, sulfates and other naturally-occurring materials.
Subsurface mining can generate mine water created from seepage into excavated areas and collected in underground sumps. It is then pumped to the surface where it can be deposited into settling ponds. This wastewater also needs to be treated in order to become potable for reuse in mine activities.
Chemical additives require expensive transport, storage, and safe disposal costs. Electrocoagulation (EC) can dramatically reduce suspended solids without the use of chemicals. In doing so, it can economically increase the on-site potable water supply for reuse, maintaining production and preserving the surrounding environment. EC’s advantages include:
Traditional EC’s main downside, however, is its susceptibility for anode and cathode passivation and scale buildup which can cause operating efficiencies, premature shutdowns and higher electrical usage.