Groundwater Tracer Investigations to Support Remedial Investigation—Rico Mining District, Southwest Colorado, USA
Presented on Monday, May 5, 2014
Mike Wireman1, Rory Cowie2, Mark Williams3 and Robert L. Runkel4, (1)Region 8, U.S. EPA, Denver, CO, (2)Institute of Arctic and Alpine Reserach, University of Colorado Boulder, Boulder, CO, (3)University of Colorado, Boulder, CO, (4)United States Geological Survey, Denver, CO
Stream water quality throughout the western United States continues to be degraded by acid mine drainage (AMD), a legacy of hard rock mining. The Rico-Argentine Mines in southwestern Colorado consist of complex, multiple-level, inter-connected mine workings connected to a drainage tunnel discharging AMD to a series of passive treatment ponds that discharge to the Dolores River. The mine workings are excavated into hill slopes on either side of a tributary stream with workings passing directly under the stream channel. Identification and characterization of hydrologic connections between surface water, groundwater, and underground mine workings was necessary to: (1) understand the source of water and contaminants in the AMD and (2) support feasibility assessments which will allow targeted remediation strategies to be developed. To identify hydrologic connections, we utilized a combination of natural and applied tracers including isotopes, ionic tracers, and fluorescent dyes. Stream tracing was conducted to characterize stream-groundwater and stream-mine workings connections. Two sets of tracers were introduced into mine workings at multiple locations to characterize flow through the workings. Stable water isotopes (d18O/dD) show a well-mixed hydrological system, while tritium isotopes indicate a fast flow-through system with residence time of years, not decades or longer. Addition of multiple independent tracers indicated that water is traveling through mine workings with minimal obstructions. The results from a simultaneous salt and dye tracer application demonstrated that both tracer types can be successfully used in acidic mine water conditions.
Mike Wireman
Region 8, U.S. EPA, Denver, CO
Michael Wireman is retired from the U.S. EPA where he served as a National Groundwater Expert. He has a master’s degree in hydrogeology from Western Michigan University. In his current position he provided technical and scientific support to several EPA programs, other federal agencies, international programs, and to state groundwater programs. Wireman has significant experience in the legal, scientific, and programmatic aspects of groundwater management. He is a member of the Colorado Ground Water Association, the National Ground Water Association, the Geological Society of America, and is the Chair of the North American Chapter of the International Association of Hydrogeologists.
Rory Cowie
Institute of Arctic and Alpine Reserach, University of Colorado Boulder, Boulder, CO
Rory Cowie is a Ph.D. student in the Department of Geography at the University of Colorado, and a graduate research assistant at the Institute of Arctic and Alpine Research. He received an M.A. in Geography from the University of Colorado in 2010 and a B.A. in Biology from The Colorado College in 2004. His research interest is the hydrology of mountain regions, looking at surface water and groundwater interactions using environmental isotopes and biogeochemistry. The focus of Cowie's Ph.D. research is on controlling acid mine drainage by understanding the hydrogeology of abandoned hard rock mines in Colorado.
Mark Williams
University of Colorado, Boulder, CO
Mark Williams is a professor of Geography and a Fellow at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder. He is a Fellow of the American Geophysical Union and is currently a Senior Fulbright Scholar in Nepal. Williams is the lead or co-lead on several large research projects evaluating how perturbations may change the hydrology of watersheds, including an NSF-funded project focused on evaluating potential impacts of unconventional oil and gas extraction on water and air quality, mountain hydrology and climate change in the U.S., and disappearing Himalayan glaciers and watershed hydrology.
Robert L. Runkel
United States Geological Survey, Denver, CO
Robert Runkel, Ph.D., 1993, Environmental Engineering, University of Colorado. From 1992 to the present he has been a Research Hydrologist with the U.S. Geological Survey in Denver, Colorado.
