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GeoStience Services <br />2263 Kingston Road <br />Grand Junction, CO 81503 <br />(970) 759-6709 <br />EPA Protocols. To assess a mine site's potential to generate acid mine drainage, the <br />Environmental Protection Agency (EPA) provides a technical report on acid mine <br />drainage prediction (EPA 530-R-94-036) that presents a fundamental analysis for the <br />potential of acid mine drainage. Basically, acidic waters are formed by sulfide oxidation. <br />Acid is generated at <br />mine sites when metal sulfides are oxidized. For example, pyrite (FeS2), when oxidized <br />in the presence of water, creates acids by the following reaction: <br />2 FeS2 + 2H2O+'702 ~ 4H"+45042-+Fe2+ <br />The hydrogen ions (H") reduce the pH resulting in acidic conditions. The EPA report <br />notes that acid mine drainage is common in metal and coal mines. Commonly, sulfide <br />(S) minerals such as chalcopyrite, galena, and arsenopyrite, when oxidized in the <br />presence of water as shown in the above formula, produce acid drainage. <br />Conversely, common minerals for Salt Wash uranium ores and the chemical formulas are <br />listed below: <br />Carnotite: K2(U02)2(V04)2 ' 3H2O <br />Tyuyamunite: Ca(U02)2(V04)2 ~ 5-8H2O <br />Uraninite (Pitchblende): U02 <br />Evident from the chemical formulas of these uranium compounds is the lack of sulfides. <br />Consequently, there are no acid forming properties of uranium minerals compared with <br />metal minerals. Since there are reducing conditions in Salt Wash uranium deposits, there <br />is some potential for pyrite deposition, but it is not a major component like metal and <br />coal deposits. <br />2 <br />