ACID-BASE ACCOUNT EFFECTIVENESS FOR DETERMINATION OF MINE WASTE POTENTIAL ACIDITY

The oxidation of sulfide minerals in mine waste is a widespread source of resource degradation, often resulting in the generation of acidic water and mobilization of heavy metals. The quantity of acid forming minerals present in mine waste, dominantly as pyrite (FeS2) is routinely determined by acid-base account (ABA) analytical methods. The acid-base account method specifies the use of extraction techniques to determine the total quantity of acid forming sulfur compounds in a sample relative to the neutralizing potential. However, when common sulfide and sulfate minerals were subjected to ABA extraction methods, the ABA method failed to distinguish accurately the acid forming from nonacid forming minerals, resulting in errors in the determination of potential acidity. These analytical errors are subsequently reflected in inaccurate liming of acid producing waste materials resulting in either excessive cost when potential acidity is overestimated, or potential reclamation failure when potential acidity is underestimated.