Question

Acid mine drainage occurs when surface water infiltrates which of the following? A) strip-mined coal beds B) spoil banks where water chemically reacts with the minerals to create sulfuric acid C) spoil banks where chemical reactions occur with pyrite D) groundwater and surface water supplies E) none of the above

Answer 1

The correct option is C.
Acid mine drainage refers to the outflow of acidic water from a mining site. This acidic water is usually formed as a result of the chemical oxidation of pyrite [iron sulphide, FeS2]which is often found together with valuable metals. 
Acid mine drainage occurs when water flow over or through sulfur bearing materials.