Surface electrical methods have been mainly used in the prospecting for minerals, petroleum, coal field and ground water resources. With the ever expanding demand for coal as energy source, electrical survey data has increasingly become a preferred substitute for the costly drillings in locating and delineating hidden faults within the coal field, so as to minimize water discharge and provide necessary geological information for further developing operations.Special reference is given to the Feng Feng Coal mine in Hebei province where a hidden water-conducting fault with a striking length of 700 meters was accurately located in 1978. The electrical result was proved to be in full agreement with subsequent drillings. Asaving of 10 drillings and about 100,000 Yuan of engineering expenses was achieved.