Effect of Reclamation of Fluvial Tailings Deposits on Subsurface Water Quality, Upper Arkansas River Basin, Lake County, Colorado. (S11-walton-day453500-oral)
Authors:
K. Walton-Day* - U.S. Geological Survey R.W. Healy - U.S. Geological Survey
Abstract:
Fluvial mine-tailings deposited along an 11-mile reach of the upper Arkansas River floodplain resulted from mining activity in Leadville, Colorado, that started in the 1870’s. Water-quality concerns
prompted remediation from 1999 to 2001 which involved surface application and shallow tilling (to 6-inch depth) of organic (biosolids and compost) and alkalinity-generating materials. Large variations of some water-quality parameters occurred in the unsaturated zone and underlying aquifer at three
remediated sites where water was sampled using ceramic-cup lysimeters and ground-water wells from 1999 to 2003. Values of pH, specific conductance, and alkalinity ranged from 1.5 to 7.5 units, from 130 to 27,000 microSiemens per centimeter at 25 degrees Celsius, and from 0 to approximately 250 milligrams per liter as calcium carbonate. Water-quality data at two of the monitored sites showed that the unsaturated zone produced acid water, indicating that alkalinity supplied in the remedial amendments has been consumed, and (or) that infiltration of alkalinity did not occur. At the third site the unsaturated zone had near-neutral pH values and measurable alkalinity indicating that remediation has been more successful. The observed water-quality variations at the three sites may be related to differences in the remedial amendments, the amount of infiltration, or the original tailings materials. Continued monitoring will help determine the long-term effectiveness of the remediation.
Speaker Information: Katherine Walton-Day, U.S. Geological Survey, U.S. Geological SurveyDenver Federal CenterP.O, Denver, CO 80225; Phone: 303 236 4882 x 366; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 8:20 AM-11:20 AM Presentation Start: 10:20 AM
Keywords: Remediation; Fluvial Tailings; Water quality; biosolids