Monday, April 29, 2013: 4:20 p.m.
Regency West 5 (Hyatt Regency San Antonio)
Rory Cowie, University of Colorado Boulder
Mark W. Williams, University of Colorado
Mike Wireman, U.S. EPA
Long-term acid mine drainage (AMD) discharging from the portal of the Nelson Tunnel near Creede, Colorado is currently impacting water quality in West Willow Creek and the Rio Grande River. Preliminary results indicate that waters draining the mine are well mixed and composed to some degree of old groundwater, not just meteoric inputs. The stable isotope (
18O) of the mine water is steady at -15 ‰ throughout the year, suggesting a well-mixed groundwater system composed of equal parts winter snow (-20 ‰) and summer monsoon rain (-10 ‰). Tritium (
3H) values within the tunnel are primarily “tritium-dead” indicating water that is at least older than the “bomb-spike” waters of nuclear weapons testing in the 1960s. Additionally, DIC d
14C testing indicates mine water on the order of hundreds to thousands of years of age. Results therefore suggest that mine waters are largely not directly connected to surface waters, or to the shallow groundwater (springs, seeps), but rather are likely entering the tunnel at intersections with a system of watershed-wide faults and associated fractures.
To build on existing information, additional sampling will occur in the fall of 2012. We propose to use established isotope and geochemical tracer techniques to quantitatively determine the origin of waters discharging from the Nelson Tunnel. Specifically, analysis of 18O, 2H, 87Sr, 86Sr, 14C (from DIC and DOC), and 3H will help identify the sources, ages and pathways of waters in the mine.
The results from field investigations will be used to develop a hydrogeologic conceptual model of the mine complex, which will aid in the development and feasibility analysis of targeted remediation strategies. One potential outcome of the research is to identify the feasibility of well installation to control groundwater prior to interacting with the mine complex, ultimately preventing AMD production at this location.
| Rory Cowie
, University of Colorado Boulder
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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. Cowie received his 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.
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| Mark W. Williams
, University of Colorado
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Dr. Mark Williams, Fellow at the Institute of Arctic and Alpine Research Professor of Geography, at the University of Colorado, received his Ph.D in Biological Sciences with an emphasis in ecology from the University of California at Santa Barbara in 1991. The majority of his research has been conducted in the Rocky Mountains, Sierra Nevada of California, and the Tien Shan, China. Mark is on the faculty of the Hydrology Program in Geography and his classes can be used to satisfy the Hydrology Certification Program in Geography. Mark is the PI of the Niwot Ridge LTER program.
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| Mike Wireman
, U.S. EPA
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Michael Wireman is employed by the U.S. EPA where he serves as a National Groundwater Expert. He has a master’s degree in hydrogeology from Western Michigan University. In his current position he provides 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.
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