Salient points of this presentation are as follows:

Knowing the geology of the mine site is critical to understanding the environmental impact of mining at any given site.

Hydrothermal alteration associated with the mineral deposit has a major effect on the premining geochemical background as well as on the postmining environmental impact on the watershed.

U.S. Geological Survey databases containing abandoned mine sites and stream sediment geochemical data, plotted in conjunction with the locations of significant mineral deposit types, can be used to assess the scope of historical mining impacts on the environment within the Nation.

Surveys of the distribution of benthic macroinvertebrates in the Central Colorado Assessment Project show that water quality criteria are not protective of benthic macroinvertebrates.

Remedial actions based upon these water quality criteria are not sufficient to restore aquatic fisheries.

Version 1.0

Posted June 2007

• Report PDF (24 MB)