Once the coal was mined, a mineral called pyrite was exposed to air. It oxidized, turning into an acidic solution and leaving a lot of iron leftover. (High content of iron in a stream will make the stream look orange.) The acidic solution dissolves clay and causes aluminum to build up. As a result, the stream is contaminated with high levels of iron, aluminum and acidity. All three of these contaminants degrade aquatic habitat! In order to fix these problems, remediation consists of the following: limestone leach beds, anaerobic vertical flow wetlands, aerobic wetlands, sulfate reducing bio-reactors, and settling ponds. It is a lot of work to fix a stream that has been polluted!