A GEOPHYSICAL ANALYSIS OF THE KELLOGG MINES, PULASKI COUNTY, ARKANSAS

Subsidence is a serious geological, environmental and geotechnical hazard. Voids or cavities are created when resources, such as minerals, oil, coal and groundwater, are removed from the subsurface. An abandoned lead, silver and zinc mine known as the Kellogg Mines has experienced collapse of the abandoned mine tunnels and shafts. This collapse has created a series of collapse pits at the surface, which is now adjacent to new home construction. Portions of the Kellogg Mines area were investigated to determine where subsidence might occur in the future, how likely subsidence will continue in the future and the feasibility of geophysical methods in studying subsurface cavities. Aerial photographs and global positioning system (GPS) were used to assess the surface geologic and geomorphic features. A surface subsidence map was created that documents the collapse pits in this area. Magnetic, gravity and ground penetrating radar (GPR) surveys were used to investigate the subsurface features. The magnetic surveys were successful in detecting geologic features (faults) and surface collapse pits. The gravity survey was successful in detecting the faults. The GPR data was successful in detecting shallow, subsurface collapse pits and delineating the water table. The use of geophysical methods for collapse pit detection was successful. Due to the age of the mining activity, it is assumed that most collapse has already occurred, but overloading due to home and road construction may result in future subsidence activity.