THE IMPACTS OF COAL MINING ON THE TERRESTRIAL PHOSPHORUS CYCLE: AN EXAMPLE FROM THE FRIAR TUCK MINING COMPLEX, SULLIVAN COUNTY, INDIANA

Despite ceasing operations in 1952 and subsequent reclamation efforts, the abandoned Friar Tuck Mining Complex (FTMC) in Sullivan County, Indiana, continues to produce acidic drainage that impairs the local water, soil, and vegetation. Over 350 samples for geochemical analysis of metals and phosphorus have been collected from areas in need of additional remediation, areas that have been deemed successfully reclaimed, and from Pennsylvanian coal seams found within the site. Soils are generally thin and weakly developed with soil pH range from 1 – 8. Metal concentrations (Al, Cu, Fe, Pb, and Zn) in surface soils were found at or above probable effects and threshold effect levels in many areas of our study site using consensus based sediment quality guidelines (NOAA). However, phosphorus concentrations are generally low (<25 umol/g). These phosphorus concentrations are considerably lower than those found in other organic-rich deposits (up to 280 umol/g in the Pennsylvanian Excello Shale, for example) and are even lower than the values commonly seen in average soil (~30 umol/g). After completing a phosphorus sequential extraction, it was determined that the dominant form of phosphorus in these soils is adsorbed or associated with oxides. Commonly, mineral phosphorus and organic phosphorus dominate organic rich rocks. We suggest the dominance of oxide-associated phosphorus and the low overall total phosphorus concentrations at FTMC result from the environmental impacts of mining (i.e. coal mining, the production of acidic drainage, and unsuccessful reclamation efforts). It appears that these activities have resulted in a net loss of soil phosphorus at FTMC and have likely impacted the success of vegetation in some areas. These results suggest that the mining and reclamation process strips phosphorus from soils and alters the biogeochemical cycling of phosphorus within soils.