The Idaho Springs/Central City Mining District is a designated superfund site by the EPA. The mine dumps contain abundant iron sulfides (pyrite) which weather into iron-oxide and sulfuric acid. The sulfuric acid dissolves the heavy metals such as zinc, copper, manganese, cadmium, lead, and arsenic which then contaminate the soil, ground water and the surface streams.

            The Venture Gold mill removes all of the sulfides, thus eliminating the contamination. The clean tailings are deposited into a lined contained tailings area. This is the only effective method of cleaning up toxic waste dumps.