Geomechanical justification of parameters of the development system of a thick steep layer in the case of sub-stage hydraulic extraction
- 1 — Professor G.V. Plekhanov Saint Petersburg State Mining Institute
- 2 — Postgraduate student G.V. Plekhanov Saint Petersburg State Mining Institute
- 3 — Research assistant G.V. Plekhanov Saint Petersburg State Mining Institute
Abstract
An analysis of the causes of accidents associated with dynamic collapses of the roof rocks in the development system with sub-stage hydraulic extraction in the mines of OAO Prokopievskugol has been carried out. The hypothesis about the mechanism of dangerous dynamic collapses of coal and roof rocks is put forward. It is concluded that, when determining the height of the subfloor, it is necessary to take into account the width of the pushback zone formed at the boundary of the clearing works. The influence of the main geological and mining-technical factors on the parameters of the squeezing zone was studied. It has been proven that the following factors have the greatest influence on the width of the squeezing zone: the depth of the mining works, the thickness of the mined seam, the strength of the coal. Recommendations for determining the height of the subfloor, providing safe working conditions for miners in the conditions of the hydro mine Tyrganskaya are developed. The method of mining subfloors with an increased height is proposed. For its implementation the size of the squeezing zone and the length of the working jet of the hydraulic gun is calculated and the position of the undestroyed coal zone is determined taking into account these parameters. Coal massif de-strengthening in this zone is made to exclude the coal pack hang-up by, for example, hydraulic fracturing or explosion of explosive charges. The economic effect of implementing the developed recommendations has been calculated.