Projects

Quality and Hydrology of Water in a Coal Waste Pile Amended with Synthetic Soil, Chinook Mine, Clay County, Indiana

Overview by Tracy Branam and Denver Harper

---

The Chinook Mine Reclamation Site in Clay County, Indiana contains a coal-processing waste pile consisting of a mixture of coarse and fine refuse that covers approximately 120 acres. This waste pile is a significant source of acidic runoff and seepage that pollutes the surrounding drainage system.

Panoramic view of the barren Chinook Mine Reclamation Site, prior to reclamation. Click on the picture to see a more detailed view. (NOTE: The detailed view is 293 K.)

Aerial view of the Chinook Mine Reclamation Site. Click on the image to see the coal refuse area. Click again to see the location of the panoramic view.

Reclamation plans for this pile include capping it with soil material and vegetating it. Soil caps ideally result in a gradual reduction in the formation of acidic water. Acid abatement is accomplished by decreasing the amount of water and oxygen that reaches unweathered sulfide minerals buried in the refuse pile through the processes of increased evapotranspiration, reduced infiltration, and microbial oxidation of organic matter. Composition of the soil determines the extent to which these processes work.

The Chinook Site will be reclaimed using a synthetic soil enhancement, called SoilerLime, prepared by Eli Lilly and Company that blends fluidized bed combustion ash from Purdue University's coal-burning power plant with fermentation byproduct from Lilly. This product may provide more immediate benefits than a traditional soil cap as it is enriched in nutrients required for plant growth and contains alkaline minerals beneficial for neutralizing acid water occupying pores in the waste pile.

This study will document the extent of chemical alterations that develop in the vadose (unsaturated) zone of a field-scale reclamation setting. Laboratory leaching studies cannot duplicate complex reactions in the rooting zone that affect mineral solubilities and element mobilization. Seasonal changes also affect chemical reactions. A nest of soil-water samplers placed at various depths in the waste pile will be used to monitor the development of a chemical alteration zone. Ambient conditions, along with alkalinity, potential acidity, and selected elements will be analyzed to determine which components leach from the soil cap, what conditions affect the leaching process, and how deep the alteration zone extends. Chemical analyses and hydrologic measurements will provide the basis for evaluation and the means to describe alterations and attenuations occurring at the site.

The project is sponsored by the Indiana Department of Natural Resources Division of Reclamation SMART Program. The term of this ongoing project is from January 1, 2001 to December 31, 2002.

For additional information regarding this ongoing project, contact Tracy Branam (e-mail: tbranam@indiana.edu) at the Indiana Geological Survey, 611 N. Walnut Grove, Bloomington, IN 47405.