Geological Research at the IGS

Monitoring and modeling a large-scale experiment to change the direction of groundwater flow at the Blackfoot reclamation site in Pike County, Indiana

Status Start Date End Date Locations
completed Apr 1, 2008 Sep 30, 2010 Pike
Director: Greg Olyphant
Other Researchers: Jack Haddan , Robert Waddle, D. Alex Gore
Funding: Indiana Department of Natural Resources (DNR) - Division of Reclamation (DOR)
Issue: The Blackfoot Reclamation Site in Pike County, Indiana, contains a large and chronically contaminated seepage zone that is perennially discharging acid mine drainage (AMD) into a tributary of the Patoka River.
Objective: In an effort to ameliorate the problem, personnel of the Indiana Department of Natural Resources, Division of Reclamation (IDNR-DOR) are planning a large-scale experiment to change the direction of groundwater flow away from the seepage area and toward an area where it will encounter alkaline spoils prior to discharging at the surface. The study combines detailed hydrologic monitoring with groundwater flow modeling to evaluate, optimize, and diagnose all the reasons why the reclamation strategy does or does not succeed. The project will commence prior to any reclamation activities but will continue through and after the period of hydrologic manipulation so that a thorough evaluation can be accomplished.
Approach: Continuous monitoring of five water wells, two seeps and the constructed inter-spoil pond will provide evidence of any changes in hydraulic gradients and outflows resulting from the reclamation activities. The data from the monitoring network can be used to constrain a groundwater flow model for the study area. The three-dimensional, variably-saturated, groundwater flow model will allow identification of potential problem areas that would need further reclamation attention (such as locations where ponded water would seep prior to proper treatment). Water samples will be collected from pre-installed monitoring wells and surface waters, and analyzed for field chemistry and processed for travel using US-EPA approved methods. The field chemical parameters will include pH, conductivity, dissolved oxygen, and redox potential. The samples will be packed on ice and delivered to the Geochemistry Section of the Indiana Geological Survey for analysis of major ionic composition. Special attention will be given to the AMD components of iron (both total and ferrous), manganese, aluminum, and sulfate. We will also analyze the waters for alkalinity versus acidity. The ionic composition of the water samples will allow us to characterize the waters and determine major mineral equilibrium status, which, in turn, will enable predictions to be made about whether dilution or mineral precipitation will occur from the rerouted AMD. Samples will be collected at different seasons to acquire background chemistry that correlates with water-level fluctuations. Changes in the chemical composition of the waters collected from the wells and inter-spoil ponded area will provide further evidence of the efficacy of hydrologic alteration and will provide a basis for designing any final treatment strategies.
Products: Detailed data sets and model output capable of evaluating and diagnosing the large-scale experiment in hydrologic manipulation of the mine spoils area of the Blackfoot Reclamation Site as well as guidelines for design of any additional treatment systems of on-site mine waters. These deliverables will be presented in reports to appropriate agencies, as well as peer- reviewed publications, conference presentations, and a dissertation or master’s thesis.
Benefits: This collaboration will also help the IDNR-DOR and the IGS to document an ambitious large-scale experiment in hydrologic alteration that has greater implications for the future of abandoned mine land reclamation, and it will provide out-of-classroom training to graduate and undergraduate students through internships with the Center for Geospatial Data Analysis.

Groundwater flow modeling of an abandoned mine lands site scheduled for reclamation
Waddle, R.C., and Olyphant, G.A., 2010, Groundwater flow modeling of an abandoned mine lands site scheduled for reclamation. Proceedings of the 27th Annual Meeting of the American Society of Mining and Reclamation (ASMR), Pittsburgh, PA, June 5-11, 2010.

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