An Assessment of the Natural and Anthropogenic Geochemistry of the Red Mountain Creek Watershed: Ironton Mining District, Colorado
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Red Mountain Creek is located in the rich mineralized San Juan Mountains of Southwestern Colorado, where mining from the mid 1800s through the late 1970s occurred. Sampling of the Uncompahgre River in the late 1970s, which is downstream of the five tailings ponds, showed high levels of heavy metals. It was assumed the remaining mine tailings were responsible for the high concentrations of heavy metals in the waters down-valley from the deposits. Thus, in 1983, remediation began with the use of direct re-vegetation of the deposits. This remediation was required as a result of National laws, which mandated the state of Colorado and the Idarado Mining Company develop a Remedial Action Plan (RAP). Interestingly, the tailings were assumed to be the sole source. Studies over the past twenty years, have suggested for site-specific locations, the highly mineralized zones may be additional sources of inputting heavy metals into streams. We assumed that heavy metal concentrations found in the streams come from the weathering of highly complex mineral assemblages, as well as from mining activities. It was our objective to establish the geochemistry in streams in the areas above and below mining activity and remediated areas and to evaluate the impact of remediation. Water quality data were collected for Aluminum (Al), Cadmium (Cd), Copper (Cu), Iron (Fe), Lead (Pb), Magnesium (Mg), Manganese (Mn), Zinc (Zn), and temperature, specific conductance, pH and dissolved oxygen. Twenty-seven samples were filtered with a 0.45μm membrane filter and twenty-seven were left unfiltered. Samples were collected in-stream after determining discharge for each stream. The samples of RMC were evaluated by using a Shapiro-Wilks test. There is a definitive difference between pH and dissolved metal concentrations when comparing streams on the east side to west side. In addition, there were five distinct confluences with Red Mountain Creek that provided significant changes in water quality. This was due to hydrothermally altered bedrock, which had and had not been mined.
SubjectRed Mountain Creek
Natural Acid Rock Drainage
Acid Mine Drainage
Litt, Joshua (2014). An Assessment of the Natural and Anthropogenic Geochemistry of the Red Mountain Creek Watershed: Ironton Mining District, Colorado. Master's thesis, Texas A & M University. Available electronically from