Rock Geo-Mechanical State Alteration upon Entry of a Mechanized Longwall Set of Equipment into Pre-Mining Break-Down Chamber

Rapid development of coal deep mining equipment and technology, that is connected with widespread introduction of high-performance longwall sets of equipment is accompanied with an increase of economic losses in case of its possible downtime. The analysis of dismantling experience in modern Russian mines has shown that in absolute majority of cases the actual duration of re-assembling with regard to a longwall set of equipment exceeds technologically required time five and more times. In addition to that, reassembling time significantly depends on successful formation of a break-down chamber. Review results of the most wide-spread methods for break-down chamber formation in case of coal veins’ underground development with the use of modern longwall sets of equipment are presented in the article. The numerical modeling method has been applied to have a clear view of the stress-strain state (SSS) of the coal-bearing rock solid mass in the vicinity of a break-down chamber. In the furtherance of the set goal, a finite-element model of rock solid mass in vicinity of a pre-driven break-down chamber was developed to estimate qualitative nature and SSS alteration rate. The received results of computer simulation reflect the SSS distribution pattern of a solid mass, which coincides with in situ studies and allows assumption on a line of further researches.