USGS - science for a changing world

Environmental Health - Toxic Substances

Toxics Program Remediation Activities

Evaluating How Downstream Tailings Deposits Impact the Effectiveness of Remediation Plans

Type
  • Remediation Feasibility Studies
  • Remediation Performance Monitoring
  • Site Characterization
Location Upper Arkansas River, Colorado (downstream from Leadville, Colorado)
Partners
Technology
  • Final Technology To Be Determined
  • Limestone and Biosolids Amendments Pilot Tests
Contaminants
  • Metals
  • Acidic Water
Description

Tailings deposited downstream from mining sites in the Leadville, Colorado, area represent a potential non-point source of metals and acidic waters to the Upper Arkansas River, Colorado. To understand how significant this non-point source of pollution is and its impact on the effectiveness of remediation plans, USGS scientists and their partners have embarked on a study to evaluate the water-quality impacts of tailing deposits in the Upper Arkansas River's floodplain. Results show that the impact the tailings have depends on the goal of the remediation plan (total ecosystem health or attainment of water-quality criteria in the river) and on the scale of the observation (batch leaching test, ground-water samples, or downstream water-quality sampling). For example, if restoring ground-water quality is a goal of the remediation, then the tailings have had an impact. Water-quality monitoring has shown that this has happened--ground-water quality beneath the tailings deposits has been degraded (lowered pH and elevated metal concentrations). To investigate this further, USGS scientists and their partners initiated a study in 1998 to help determine the effects of remediating the tailings in-situ on the quality of ground water immediately beneath the remediated areas. The remediation consisted of incorporating limestone and biosolids into the surface of the tailings deposits. The goals of the remediation were twofold. First, to enhance the quality of the soil so the sites can be revegetated, and second, to increase the quality of ground water 1-meter below the surface through the percolation of alkalinity generating solutes. Preliminary results of ongoing water-quality monitoring are mixed and indicate that some of the soluble products of the incorporated limestone and biosolids have percolated into the shallow ground water. However, increased alkalinity from the remediation is not penetrating beyond 30 centimeters, indicating that acid-producing materials in the unsaturated zone of the tailings deposits are consuming the alkalinity generated by the limestone. USGS partners have used these results to redesign subsequent remedial plans for the fluvial tailings deposits. In summary, this project shows the importance of monitoring to assess the effects and performance of the remediation.

More Information
Contact
  • Kathleen Smith, U.S. Geological Survey, Crustal Imaging and Characterization Team, Denver, CO,
  • Katie Walton-Day, U.S. Geological Survey, Denver, CO,
Publications
Smith, K.S., Walton-Day, K., and Ranville, J.F., 1999,
Considerations of observational scale when evaluating the effect of, and remediation strategies for, a fluvial tailings deposit in the Upper Arkansas River Basin, Colorado, in Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999--Volume 1 of 3--Contamination from Hardrock Mining: U.S. Geological Survey Water-Resources Investigations Report 99-4018A, p. 131-138.
Smith, K.S., Walton-Day, K., and Ranville, J.F., 2000,
Evaluating the effects of fluvial tailings deposits on water quality in the upper Arkansas River basin, Colorado--Observational scale considerations, in Proceedings from the Fifth International Conference on Acid Rock Drainage, Denver, Colorado, May 21-24, 2000: Littleton, Colorado, Society for Mining, Metallurgy, and Exploration, v. II, p. 1415-1424.
Smith, K.S., Walton-Day, K., and Ranville, J.F., 2001,
Considerations of observational scale when evaluating the effect of, and remediation strategies for, a fluvial tailings deposit in the upper Arkansas River Basin, Colorado, USA [abstract], in Proceedings of the Earth System Processes Global Meeting, June 24-28, 2001, Edinburgh, Scotland.
Walton-Day, K., Healy, R.W., Maestas, F.B., and Ranalli, A.J., 2000,
Effects of remediation on geochemistry and hydrology of the unsaturated zone of fluvial tailings deposits in the floodplain of the upper Arkansas River, Colorado, in Proceedings from the Fifth International Conference on Acid Rock Drainage, Denver, Colorado, May 21-24, 2000: Littleton, Colorado, Society for Mining, Metallurgy, and Exploration, p. 1443-1450.
Walton-Day, K., Rossi, F.J., Gerner, L.J., Evans, J.B., Yager, T.J., Ranville, J.F., and Smith, K.S., 2000,
Effects of fluvial tailings deposits on soils and surface- and ground-water quality, and implications for remediation--Upper Arkansas River, Colorado, 1992-1996: U.S. Geological Survey Water-Resources Investigations Report 99-4273, 100 p.
Links

USGS Acid Mine Drainage Remediation Projects

Back to Toxics Program Remediation Activities Index

USGS Home Water Land Resources Science Systems Ecosystems Energy and Minerals Environmental Health Hazards

Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: toxics.usgs.gov/topics/rem_act/tailings_final.html
Page Contact Information:
Page Last Modified: Friday, 29-Apr-2016 14:29:21 EDT