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(in mining), natural or artificially induced disruption of the stability of a rock mass. In underground mining, caving takes place as the collapse of blocks and pieces of rock into mine workings, detachment of sections of the roof rock, or shifting of an entire undermined rock stratum. Natural caving over a large area (roof sagging) is caused by dynamic loading on the mine workings and by air shocks within them. The harmful consequences of caving are prevented or minimized by the installation of supports in the workings and by controlling the behavior of the wall rock. An efficient and economical method of controlling rock pressure in long stoping faces (longwalls) is complete or partial roof caving.
The parameters of roof caving—the rate of caving of the immediate roof, which is brought about by the removal or shifting of the supports, and the rate of caving of the main roof—are determined by the properties of the rock, the depth, and the engineering and technological conditions of the operations. In the case of strong roof rocks that tend to overhang, artificially induced caving by means of explosives, hydraulic working of the rock mass, and other methods must be used. In underground mining of ore deposits, the principle of caving ores and surrounding rock in certain mining systems is the basis of mineral extraction technology. The principles governing rock caving in underground mining are studied for the purpose of designing mining systems and improving methods for the design of support and regulations for the protection of excavations and above-ground structures. In open-pit mining, the banks and rims of quarries are caved. They are made stable by the choice of the proper height and slope angle of the banks and rims, and also by anchoring the slopes, taking into account the structure, physicochemical properties, and loading. Under favorable conditions, self-caving of banks is used for separating rock from the rock mass.
V. V. ZHUKOV