Premining investigations are the activities necessary to acquire information for economic evaluation and engineering design of a mine, subsequent to reconnaissance exploration and prior to mining. The Bureau of Mines is doing research on methods to obtain premining information on problems such as detection of old mine workings, abandoned oil wells, channel sands, faults, and other geologic features that are undesirable from a production or safety aspect. Techniques being developed to acquire the necessary information fall into two primary categories: seismic and electromagnetic. The seismic methods include high-resolution seismic and acoustic methods applied from the surface and inseam channel waves applied underground. The electromagnetic, or radar, methods are applied from the surface, from boreholes, and from the working face underground. All of these methods are useful under certain site- specific conditions, but none of these methods are universally applicable for all coal mining conditions.
2nd Int'l. Coal Explor. Symp., Denver, 10/1-4/78; Miller Freeman Pubs., Inc., California, PP. 313-327