ABSTRACT

Of the major metal mining industries, gold mining is the most waste intensive (Da Rosa and Lyon 1997). Refined gold consists of but 0.00015% of all raw materials used in the gold-mining process. It is estimated that it takes 2.8 tons of gold ore to produce the gold in a single wedding band, the rest being waste (Da Rosa and Lyon 1997). After waste rock is removed and the ore extracted, the ore is processed to separate the gold from the valueless portion of remaining rock which is known as tailings. Mine tailings and waste rock contain heavy metals and acid-forming minerals. Tailings can also contain chemicals used in ore processing. Amounts of toxicants in tailings — including arsenic, lead, cyanide, and sulfuric acid — are deleterious to fish and other wildlife. Tailings are usually stored in piles on land or in containment ponds, but sometimes are pumped back into the underground space from which the ore was mined. Dumping of mine tailings directly into rivers or other water bodies is no longer allowed in the United States, but occurs with some frequency elsewhere, especially in developing countries (Da Rosa and Lyon 1997).