Rates and Controls on Toxic Metal Leaching from Coal-Combustion Residues Utilized as Structural Fills in Reclamation Settings: Emphasis on the Midwestern AML Site

Status Start Date End Date Locations
completed Feb 1, 2011 Aug 31, 2014 Pike
Director: Tracy Branam
Other Researchers: Shawn Naylor, Greg Olyphant E. Randall Bayless, USGS Jack Haddan Denver Harper
Funding: Indiana Department of Natural Resources (DNR) - Division of Reclamation (DOR)
Issue: Previous investigations of toxic metal occurrence in ground and surface waters at the Midwestern AML Site have documented the sporadic occurrence of trace element concentrations in ground and surface water samples over time.
Objective: The project, which combines field, laboratory, and modeling components, will determine the conditions under which trace elements are leached from CCRs in field settings as well as rates of leaching when CCRs are in contact with various ambient water chemistries.
Approach: Hydrologic monitoring along with chemical analyses of several target trace elements will be utilized in our evaluation of solids and solutes associated with coal combustion residues present at the site. We will also determine stability of dissolved trace elements in mine waters and the likely conditions under which the dissolved metals precipitate.
Products: 1. Detailed data sets capable of being used to evaluate the potential for, and rates of, trace element leaching from CCRs that come into contact with waters of varying initial chemical composition. 2. A detailed understanding of the movement of water and fate of trace elements in CCRs used as structural fill in reclamation settings. 3. A set of guidelines for using CCRs in reclamation settings aimed at minimizing or avoiding adverse hydrochemical outcomes. These deliverables will be presented in a technical report to the Indiana Dept. of Natural Resources (Division of Reclamation) and a Web site report, as well as peer reviewed publications, conference presentations, and one or more graduate student thesis.
Benefits: The results of the work will allow us to predict the outcomes of utilizing CCRs in reclamation settings and to develop guidelines for minimizing deleterious effects of using CCRs as capping materials and structural fills.