Application of Short-Offset TEM (SOTEM) Technique in Mapping Water-Enriched Zones of Coal Stratum, an Example from East China

Water inrush from limestone coal beds is disastrous for coal mining. In general, it is very difficult to detect such water-enriched zones because of their relatively large burial depth. In this paper, we propose a novel transient electromagnetic method (TEM) configuration, short-offset transient electromagnetic method (SOTEM). Consistency of the results obtained from SOTEM measurements in the Shandong province, East China and drilling information indicate that the proposed TEM configuration not only improves the accuracy, but also enlarges the exploration depth for detecting water-enriched areas in coal mines ranging from 1,000 to 1,200 m depth. In this region, a majority of the deep coal beds are filled with water. The SOTEM technique was successfully employed in detecting the floor of a coal seam at a depth of about 1,500 m, as well as in identifying the location of the water-saturated area. These findings were later confirmed by subsequent drillings. Thus, our study indicates that SOTEM represents a convenient and effective technique for deep mineral and hydrogeological investigations due to its high sensitivity to conductive zones (water enriched areas) and vertical resolution.