Horizon control holds key to automation.
Coal, Pt. 1, 1991 Dec; :44-48; Pt. II, 1992 Jan; :47-51
A coal-rock interface detector (cid) system is integral in providing coal seam tracking capability for mining machines. The cid system must be able to measure one or more properties of coal and adjacent formations and, subsequently, must be able to identify the geologic material being cut, to locate the coal-rock interface, and/or to determine the thickness of the coal remaining below the roof or above the floor. Various types of commercial and experimental cid systems are being used, and novel cid concepts are being investigated by the U.S. Bureau of Mines and other research organizations throughout the world. Cid systems can be used for both manually operated and computer-assisted mining equipment. More than 20 types of cid concepts have been investigated in the United States and abroad during the past 30 years. Of these, only the natural gamma radiation concept has been successful enough to be made into a commercially available system. It is being used on longwall shearers and continuous miners in britain and on some highwall mining machines in the United States. This technique is also being evaluated on a limited basis in the United States on continuous miners and longwall shearers. Technical information on some of these systems has been published, but details on other systems have been closely guarded. Consequently, it is difficult to accurately describe and assess the performance of every cid system.
Coal, Dec. 1991, PP. 44-48 (Pt. I); Jan. 1992, PP. 47-51 (Pt. II)