Effects of Siderite on the Neutralization Potential in the Acid‐ Base Account

Siderite has long been recognized as a potential source of error in the determination of neutralization potential within the acid base account procedure. Siderite is Iron Carbonate which will contribute alkalinity to the neutralization potential (NP) analysis, while the iron generated acidity is not measured by the acid potential (AP) analysis. While this interference has been recognized it has generally been assumed that there was not enough siderite present to influence the acid‐base account result. In 1992, V. P. Wiram reported on effects of siderite masking at the Skyline Mine. Failure to recognize the presence of siderite in the overburden resulted in post mining seeps which were above discharge limits for iron. In 1990 J. Morison reported on the use of hydrogen peroxide in the AP test as a means of eliminating siderite masking. This report incorporates hydrogen peroxide addition along with a modification to the application of the fizz analysis in order to eliminate the effects of siderite and to reduce the subjectivity of the fizz test.