Mine Water Chemistry

The minerals and coal that represent economically valued ores are largely chemically stable under in situ geological conditions. When excavated and exposed to the atmosphere, however, these solid phases become chemically unstable. Coal and hydrocarbons can be oxidized through combustion to gain useful energy. The sulfide minerals associated with metal ores and present as sulfur contamination in coal will spontaneously dissolve when in contact with water. The chemical weathering of sulfide minerals represents a series of linked geochemical and microbiologically-mediated reactions through which contaminants are released from ore and mine waste into the hydrological cycle and become mobile and thus bioavailable as potentially toxic solutes.