ZAPATA has developed comprehensive mine subsidence investigations to delineate mine workings, evaluate subsidence risk, and develop mitigation strategies. We can map the void size and geometry using borehole laser (for air-filled voids) or sonar tools (for water-filled voids) and image void conditions using video camera capabilities.
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ZAPATA has implemented an ongoing engineering – geophysical program, investigating mine subsidence problems associated with multi-level underground coal mines at depth ranging from 50 to 400 ft in residential areas and undeveloped properties. The ZAPATA team has demonstrated its integrated approach as invaluable to the AML 17.6A project, providing cost-effective and focused solutions at lower overall cost than the traditional approaches.
ZAPATA performed the investigation in support of MSHA initiative “Geophysical Void Detection Demonstrations” to advance the current state-of-practice of geophysical technologies for detecting underground mine voids. ZAPATA employed several surface and borehole geophysical mapping methods and downhole void scanning/imaging techniques at a known abandoned room and pillar coal mine at a depth of approximately 235 ft. These methods included: 1) surface high-resolution 2D and 3D seismic using P-wave (HRPW) and S-wave (HRSW) reflection; 2) crosshole seismic tomography (XHT); 3) seismic guided waves (GW); 4) reverse vertical seismic profiling (RVSP); and 5) downhole sonar imaging of the flooded mine workings.
ZAPATA performed several mine subsidence investigations for DRMS in support of its Inactive Mine Reclamation Program (IMRP). These projects provided invaluable information for DRMS to design and implement a mitigation program. ZAPATA employed a suite of surface and downhole geophysical mapping methods delineating old mine workings beneath the residential area of the CCC.
ZAPATA conducted a mine subsidence investigation to map abandoned Baseline coal mine workings at depth ranging from 20 to 90 feet beneath the planned Vista Ridge development site. The extent of partially undermined areas beneath the southern edge of the property is not well defined and the accuracy of the historical mine map is not known. ZAPATA performed a borehole geophysical survey using the reverse vertical seismic profiling (RVSP) method. The RVSP line extended approximately 400 linear feet overlaying both the supposed mined and unmined areas in the east-west direction, and paralleling the southern edge of the property.
