Limestone Quarry Expansion: Georgia
Leggette, Brashears & Graham, Inc. (LBG) completed a comprehensive hydrogeologic assessment for the expansion of an aggregate limestone quarry. The existing quarry had been continuously mined since 1935 and the client’s expectations were to expand the pit laterally 4,400 feet and vertically 75 feet, while also being protective of the environment. The state regulatory agency required the client to evaluate the potential impacts of proposed quarry dewatering activities on ambient and groundwater conditions in the karst regime, such as drastically lowering the groundwater level (even at considerable distances from the quarry), modifying the surface-water flows of adjacent streams and springs, and/or inducing land subsidence and sinkhole collapse. In addition, the state required evaluations of other natural resources including water supplies, streams and surface-water bodies, springs, wetlands and riparian wetlands, and threatened and endangered species.
SCOPE OF WORK
The following hydrogeologic assessment activities were completed to support the permit application:
Geologic characterization and conceptual hydrogeologic modelingRemote sensing and fracture-trace analysis
Design and installation supervision of seven 300+ foot deep monitor wells
Borehole geophysics including color down-hole video inspections and borehole flowmeter logging
Identification of areas around the expansion pit potentially susceptible to quarry dewatering
The following geographic information system (GIS) maps and classifications were also completed to access the natural resources within a two-mile radius of the proposed quarry expansion.
– Surface-water flow and basin analysis
– Stream assimilation of waste
– Wetlands and jurisdictional streams
– Riparian woodlands
– Trout streams and potential threatened and endangered species
In addition to the hyrdogeologic and natural resources evaluations, the state’s Surface Mining Act required the preparation of a detailed monitoring and mitigation plan.