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<br />MODIFICATION OF TlIE NET ACID PRODUCTION (NAP) TEST <br />Kim Lapakko' and Richard W. Lai .,::~..e' <br />In Proceedings of the Seventeenth Annual British Columbia Mine Reclamation Syrrtposium, Port <br />Hazdy, British Columbia, May 4 to 7, 1993. p. 145-159. <br />ABSTRACT <br />The Net Acid Production Test (NAP) was developed as a hydrogen peroxide-based static test <br />for the prediction of acid rock drainage which could be applied in the field. Previous evaluation <br />indicated the test underestimated the Net Acid Production Potential of mine waste samples. <br />Recognizing that this error might have been the result of incomplete oxidation of {ron sulphide <br />minerals in the mine waste, modifications to the test were introduced, primarily to enhance the <br />degree of oxidation. Ten mine waste samples were characterized (particle siz@, chemistry, <br />mineralogy) and subjected to the modified NAP test, standazd Acid Base Accounting, Modified <br />Acid Base Accounting, and the B.C. Research Initial static tests. The results of the NAP test <br />were quantitatively comparable to those of the other static tests. Comparison of the sulphur <br />content of four samples before and afrer the NAP Tes[ indicated that 95 to 99 pr=rcent of the <br />sulphur initially present was oxidized by the hydrogen peroxide digestion. It was concluded that <br />the modification improved the extent of iron sulphide mineral oxidation and, consequently, the <br />accuracy of the test. <br />' Division of Minerals Minnesota Department of Natural Resources, <br />Box 45, 500 Lafayette Road, St. Paul, MN 55155-4045 <br />2 Department of Mining and Mineral Process Engineering, <br />University of British Columbia, Vancouver, B.C. V6T 1Z4 <br />145 <br /> <br />