The Pennsylvania Mine was initially developed in 1879. It produced gold, silver, lead, copper and zinc and had its biggest production year in 1893 when it shipped 7,000 tons of ore. The mine was developed on six levels, known as A, B, C, D, E and F with F being the lowest level. Adits were constructed at levels C and F. The mine continued regular operations until 1908 and was then worked intermittently until the mid-1940s when it was abandoned.
Since being abandoned, metals-laden effluent has flowed from the level F adit, down a steep channel and directly into nearby Peru Creek, which is a tributary of the Snake River. In addition to this acid mine drainage, significant waste and tailing deposits remain on the surface near both the level C and level F adits. These deposits are often eroded into the creek during large runoff events.
Both Peru Creek and the Snake River are listed on Colorado’s 303(d) list of impaired water bodies. Data collected since the 1980’s by various parties suggest that the mine is the largest single anthropogenic source of heavy metals in the Peru Creek and Snake River watershed.
see The Pennsylvania Mine video at: EPA Emergency Response: Pennsylvania Mine
