Sulfide Oxidation

Mining accelerates the rate of exposure of rock to air and water. Under these conditions sulfide minerals oxidise and generate dissolved sulphate which often leads to acidic pH conditions and an increase in the metal concentrations of water that seeps from the rock.

 

The oxidation of sulfides and mobilization of metals can be both beneficial and problematic. Oxidation in heap leach piles mobilizes commodities, for example copper, which are then recovered as a product. In contrast oxidation in stockpiles can lead to a reduction in copper recovery when the stockpiled ore is processed. Environmental impacts can result from acid mine drainage and metal bearing effluent generated by some sulfide bearing waste rock dumps and tailings dams.

 

Oxidation of mined sulfides in dumps or dams is supported by the supply of oxygen from the atmosphere and the rate of oxidation depends, in part, on the rate of oxygen supply and the oxygen distribution.

 

SRK has extensive experience in determining the distribution and the rate of oxygen supply in dumps of mined rock and assisting mining companies in developing strategies to manage sulfide oxidation.