METHOD FOR GEOELECTRIC PROSPECTING FOR PROGNOSIS OF STATE OF SECTIONS OF INHOMOGENEOUS ROOF OF COAL SEAMS Russian patent published in 1994 - IPC

FIELD: geoelectric prospecting. SUBSTANCE: grounded in two mine workings are current-carrying electrodes A and B and measuring electrodes. Electric field is excited through current- carrying electrodes, and its value is measured by means of measuring electrodes. In this case, electrodes are moved in compliance with preset scheme of motion. One current-carrying electrode A is grounded in one mine working and first measuring electrode M is grounded near electrode A. At distance of 15.2 km from them, second current carrying electrode B is grounded and second and third measuring electrodes N1 and N2 are grounded in other mine working. In so doing, all electrodes are grounded in low-resistance roof rocks and electric field is measured simultaneously by varying distance between electrodes M, N1 and N2. EFFECT: higher efficiency. 13 dwg