Determination of chemical-constituent loads during base-flow and storm-runoff conditions near historical mines in Prospect Gulch, upper Animas River watershed, southwestern Colorado

Copper isotope fractionation in acid mine drainage

“…These sulfides have presumably been weathering naturally since exposure and since the onset of mining. As a result, acidic, metal-rich ARD and AMD now impact the area (Wirt et al, 1999;Bove et al, 2000).…”

Hydrochemical variations and contaminant load in the Río Tinto (Spain) during flood events

“…Several studies have investigated the hydrochemical responses of small catchments affected by AMD (Gammons et al, 2005;Lambing et al, 1999;Sandén et al, 1997;Wirt et al, 1999) while the temporary storage of metals by salt mineral formation in dry periods followed by dissolution and metal release by rainfall/flood events has been studied or proposed as an important physicochemical process in a number of other works (Alpers et al, 1994;Bayless and Olyphant, 1993;Cravotta, 1994;Dagenhart, 1980;Hammarstrom et al, 2005;Keith et al, 2001). Table 5 compares the characteristics of flood events in this study with Contrary Creek, Virginia (Dagenhart, 1980) and Boulder Creek, Iron Mountain, California (Keith et al, 2001).…”

Preliminary release of scientific reports on the acidic drainage in the Animas River watershed, San Juan County, Colorado

“…The chloride concentrations used for tracer-dilution discharge calculations and loads were analyzed using an ion chromatograph (1C) at a USGS laboratory in Denver, Colorado. The accuracy for the discharge measurements using the tracer-dilution technique was about + 5 percent for low-range chloride concentrations and + 3 percent for high-range chloride concentrations as described in Wirt et al (1999).…”

“…The day before the tracer injection, field reconnaissance was conducted in order to select appropriate tracerdilution and water-quality sample sites, to estimate stream velocity in the study reach, and to measure discharge at the outflow of the study reach. Field measurements at more than 30 sites included specific conductivity, pH, and water temperature (Wirt et al, 1999). Station numbers were assigned according to the distance downstream from PG-0 in meters; for example, PG700 is 700 m downstream from PG-0.…”

“…2), encompasses the margins of an extensive 23 Ma acid-sulfate hydrothermal system with related Ag-Cu-Au breccia pipe and fault-hosted mineralization (Bove et al, 1999). Recent studies indicate that both natural and mine-related waters within the study area are major contributors of iron, aluminum, zinc, and other trace metals to Cement Creek, a major tributary of the upper Animas River (Bove et al, 1998;Wirt et al, 1999).…”