Detection of Cavity Using Electrical Resistivity Tomography (ERT) at Patherdih, Jharia Coal Field, Dhanbad, India

摘要

Geophysical survey for cavity detection is one of the most common near surface application. The usage of resistivity methods are also very straightforward for the air filled underground voids, which should have theoretically very high resistivity in the ERT image, whereas the water filled cavities have low resistivity in Electrical Resistivity Tomography (ERT) image. Three different geoelectric arrays Wenner, Schlumberger and Dipole-dipole are applied for detecting cavities. The survey results suggest that ERT is a viable geophysical tool for the detection and monitoring of mining voids and other subsurface cavities. The resolution capacity of joint Wenner-Schlumberger, Dipole-dipole array for the detection of cavity is greater than that of the individual one. Using the ERT survey in Patherdih Thana Basti village (Jharia coal field), a number of air filled cavity or water filled mining voids are detected at around 25-30m of below the ground level at different profile distance of 630m profile length along the road that extending S-E to N-W direction.