CHARACTERIZATION AND CONTAMINATION ASSESSMENT OF MINE WASTE PILES AND SEDIMENT MATERIALS IN GILPIN COUNTY, COLORADO

This research project was designed to determine environmental effects of Gilpin County waste rock piles on water in the Russell Gulch area. Each waste rock pile assessed was compared on proximity to ephemeral gulch, extensiveness of erosion features, and development of a cementation crust. Other physical criteria such as location, size, vegetation, grain size, kill zone, drainage, equipment access, and mineralogy were also noted. After collecting samples from each location leach tests developed by the Colorado Division of Minerals and Geology and USGS, as well as the EPA TCLP test where run on each sample. Waters collected in the area and waters produced by the leach tests were all subjected to a standard analytical procedure. These tests included, pH, Eh, conductivity, alkalinity or acidity, and analysis for 31 metals using inductively coupled plasma, atomic emission spectroscopy. After completion of each of the leach tests and physical assessment of each site, a rating was assigned to each waste rock pile on its overall potential to deliver contaminants. From the physical assessment and chemical tests, an overall rating on the ability of each waste rock pile to deliver contaminants to Russell Gulch is determined. These ratings will be used to establish clean-up priorities in the area.