Abstract
As known, the main methods of developing solid minerals are open and underground methods. However, an analysis of the world’s practice of developing deposits of solid minerals also indicates the widespread use of the combined method of development in the last 50-60 years. Combined development of deposits at domestic and foreign mining enterprises is used due to the variable depth of deposits, which is typical mainly for deposits of steep and inclined fall. The essence of the combined development is that the upper horizons are developed in an open way, and the lower ones are developed underground. In such deposits, the following scheme has become widespread: the initial development of the upper section of the deposit by a shallow quarry (up to a depth of 80-100 m, sometimes more), then the construction of an underground mine, carried out in parallel with the completion of the quarry reserves. When opening sub-quarry reserves subject to underground mining, the resulting quarry space can be used. The penetration of vertical and inclined opening workings, tunnels, and exits from the berm sides or directly from the bottom of the quarry has become widespread. In parallel mining of reserves by open and underground methods, the joint use of transport workings is widely used for the delivery of ore mass from the quarry and underground mine, the placement of an underground crushing complex, auxiliary, and repair facilities in the quarry itself. In addition, the method of refining sub-quarry reserves with the opening of the underground part outside the quarry space has been widely used. After the end of open-pit mining, underground horizons are opened by capital mining workings (vertical, inclined shafts, tunnels).