INCROP ZONE DEMARCATION OF COAL SEAM USING ELECTRICAL RESISTIVITY TOMOGRAPHY-A CASE STUDY OF A COAL BLOCK IN THE MAIN BASIN OF THE SINGRAULI COAL FIELD

Delineation of Coal seam incrop zone is necessary for mine economics and coal conservation during mining operation. In this study demarcation of the incrop zone of a coal seam has been done by using the Electrical Resistivity Tomography method of Geophysical Electrical Resistivity survey. The resistivity data acquisition of the subsurface has been carried out by a 48-channel resistivity meter in the incrop zone of coal seams of the Main basin of the Singrauli coalfield. The resistivity of the subsurface in 2D sections along the 1000m survey lines is measured and plotted with the help of inversion techniques using RES2DINV software to depict the actual lithology of the subsurface in an Electrical resistivity imaging survey. The resistivity of the subsurface varies according to the geological characteristic of the rock, porosity, saturation of water, mineral and fluid content, etc. in the rock, and the resistivity of coal seams is generally higher than sedimentary country rock. The characteristics of higher resistivity of coal seam compared to country rock are helpful to demarcate the actual position of coal seam incrop zone. Resistivity variations of the subsurface are well correlated with geological formation as provided in available borehole lithology. Electrical Resistivity Tomography is effectively used to delineate the incrop zone of coal seams. The resistivity imaging survey is more economical and environmentally friendly in comparison to the conventional drilling method to prove the incrop zone of the coal seam.