APPENDIX 1
Sulfuric acid generation is caused in acid mine generation if the combination of oxygen (the oxidization agent), water, and sulfur-containing rocks are present at a location.
Present in the Belt-Sand Coulee Coal Fields are large quantities of pyrite nodules, which are crystallized iron disulfides (FeS2) and a large source of sulfur for the oxidization process to acid (4).
The recognized oxidization process is given below:
2FeS2 + 2H2O + 7O2 
2FeSO4 + 2H2SO4
Pyrite is oxidzied by air and water to form ferrous sulfate and hydrogen sulfate (sulfuric acid). Then
4FeSO4 + O2 + 2H2SO4 2Fe2(SO4)3 + 2H2O
the sulfuric acid is used to further oxidize the ferrous sulfate to ferric sulfate. The ferric sulfate can be hydrolized to form further acid:
Fe2(SO4)3 + 6H2O 2Fe(OH)3 + 3H2SO4
The ferric hydroxide is can be precipitated if the receiving waters are at higher acidic pHs. The ferrous sulfate can also oxidize additional sulfides. This process can be helped along considerably by the presence of oxidizing bacteria (4).
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