Coal Complexes

(stoping complexes, cutting complexes), face-working equipment consisting of a narrow-web stoping machine (cutter-loader or scraper-loader), a mobile face conveyor (that is, a conveyor that can be relocated without being dismantled), and a mechanized support. A mobile base beam that guides the movement of the support sections may be used with the coal complex instead of the face conveyor when working steep seams (slopes greater than 35°).

Coal complexes are designed for the integrated mechanization of the basic mining processes at the working face: breaking the coal out, loading coal onto the face conveyor, conveying (delivering) the coal, moving the face conveyor, and holding up the roofs. Coal complexes are used in longwall operations for extracting coal in seams 0.7 to 3.5 m thick, dipping at 0° to 90° angles. Work is under way (1973) on the use of complexes for cutting coal seams less than 0.6 m thick and single-layer seams up to 5.5 m thick and also for working under more complex mining and geological conditions (such as weak side rocks, non-collapsible roofs, or geologically disrupted seams).

The first coal complex (the MPK brand) was tested in 1954 in the USSR. The coal complexes in series production in the Soviet Union in 1973 are shown in Table 1.

The use of coal complexes has made it possible (in comparison with the wide-web cutter-loader cutting method and individual props) to increase loading at the working face by two to three times and raise labor productivity by two to 2.5 times while significantly improving safe working conditions and lowering the net cost of extracted coal by at least 1–2 rubles per ton. In 1972 more than 43 percent of all the coal mined in the USSR from gently dipping and inclined seams was extracted by means of coal complexes; this figure rose to 59.8 percent in 1975. Under favorable mining and geological conditions, high production and economic targets are achieved with the use of complexes: a daily coal output of 5,000 to 6,000 tons at a labor productivity rate of more than 60 tons per man at the working face.

Coal complexes create the prerequisites for the introduction of automatic and remotely controlled mining equipment systems (including those run from a remote central control panel placed in the drift) in which all production processes at the working face are performed without the constant presence of workers. New horizons are thus opened up for the safe extraction of coal in seams made hazardous by sudden coal outbursts and gas blowouts and also in very thin seams that dip either gently or steeply. Experimental models of coal complexes with automatic and remote control systems passed industrial tests in the USSR in 1973 and have been industrially produced since 1975. The use of complexes represents a general trend in the integrated mechanization of longwall mining.

Coal complexes are widely used in Great Britain, West Germany, France, Czechoslovakia, and elsewhere. Longwall coalstoping complexes are being introduced in the USA.