On April 24, 1999 Office of Surface Mining Director, Kathy Karpan dedicated the Patoka South Fork Watershed Lick Creek Project. The southern Indiana project, which was the direct result of the Appalachian Clean Streams Initiative, shows the impact that local citizens can have when they organize and work together with state and federal agencies, private industry, and universities to accomplish acid mine drainage restoration.
Before restoration the Lick Creek site consisted of two connected abandoned coal mine pits surrounded by acid producing surface mine spoil. While minor acid seeps into the lakes existed, most of the acid mine drainage pollution resulted from subsurface water flowing into the lakes.
Because of physical site constraints, a totally new and experimental passive treatment system was use. The system capitalized on the low dissolved oxygen levels in the lower portion of the lake to create an "Aqueous Anoxic Limestone Drain." The concept involved the construction of a porous limestone dam, which allows flow only through the lower anoxic portion of the limestone. Construction of the dam allowed the downstream portion of the lake to serve as a precipitation pool and repository of metal oxides and hydroxides, thus protecting the valuable wetland environment downstream.
Within two weeks of completion, the drainage into the wetland began to show dramatic improvement. Acidity was reduced by 52 percent, pH has risen from 2.9 to 5.6, iron concentration dropped from 40 ppm to 2.3 ppm, and the precipitation of metals in the downstream wetland had ceased.
For additional information contact the Patoka South Fork Watershed Steering Committee at psfwsc@sigecom.net
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