Efficiency evaluation of roof rock control in conveyor drift 555 in Chertinskaya-Koksovaya Mine

Abstract

The depth of coal mining in Kuzbass reaches 600 m and more. The geological, geomechanical and gas-dynamic conditions of mining persistently complicate. In this respect, it is required to undertake additional geomechanical research of rock masses in order to select the most effective approach to ground control. Deeper level mining induces higher stresses in enclosing rocks and at the boundaries of roadways. This article describes the studies into the geomechanical processes outside and inside the zone of roof rock destressing in conveyor drift 555 in Chertinskaya-Koksovaya Mine, and the determined values of horizontal and vertical displacements in rocks. As the face of conveyor drift 555 was advanced, intense displacements took place in the roof, floor and sidewall rocks of the roadway, which greatly affected its operating conditions. The implemented work package included geomechanical and geophysical research, in situ measurements, adjustment of the behavior and structure of enclosing rocks, as well as development of roof control and validation of the selected parameters with due regard to the actual condition of rock mass, which enabled reduction in the adjacent rock mass movements, improved serviceability of roof support and preserved the roadway cross-section. The dipole electromagnetic sounding of the floor rocks susceptible to swelling determines the destressing depth; the product of the floor destress depth and the rock expansibility allows evaluating potential displacement of the floor rocks. The roof rock destressing made it possible to reduce displacements in the roof from 607 to 58–0 mm, which ensured maintenance-free support of the roadway. The studies proved the main roof rock destressing efficiency at the selected parameters, which ensured sufficient operating conditions in the drift for the whole service life.