COMPARISON OF HYDROLOGIC CHARACTERISTICS FROM TWO DIFFERENTLY RECLAIMED TAILINGS PONDS; GRAVES MOUNTAIN, LINCOLNTON, GA

This study compares and evaluates the hydrologic characteristics between two kyanite ore process tailings ponds that were reclaimed with different reclamation strategies; one reclaimed with an impermeable membrane and the other with an open, surface reconfiguration methodology. During the extraction and processing of kyanite ore from the Graves Mountain mine, Lincoln County, Georgia, fine grained tailings were produced. The tailings were transported by slurry pipeline to various tailings ponds which were created by the construction of dams using on-site materials. The first study site, referred to as the Pyrite Pond (PP), was constructed and filled during the 1960’s and early 1970’s. In early 1992, the PP was capped with an impermeable membrane, covered with a thin soil veneer and vegetated and in 1998 the upslope reclamation was completed. The second tailings pond, referred to as the East Tailings Pond (ETP), was constructed and filled in the 1970’s and early 1980’s and was reclaimed in 199596 by surface reconfiguration and the addition of soil amendments. Piezometers and wells were installed into the two tailings ponds and also in close proximity to the tailings ponds. While the initial study was aimed at comparing the two reclamation strategies, it became apparent that the ground water was a dominant factor. Results of the evaluation of the potentiometric surface data for varying depths within each tailings pond indicate that while both tailings ponds exhibit delayed response to precipitation events suggesting infiltration effects, the delay in the ETP deep wells and PP wells could not be adequately described by a surface infiltration model. Further consideration of the surrounding well data, coupled with the tailings cross sections and water levels, suggest that the hydrologic characteristics of both tailings ponds are significantly influenced by base flow infiltration and ground water seepage into the upgradient areas of the tailing ponds. Additional