Investigation of processes of rocks deformation and the earth’s surface subsidence during underground coal mining

Abstract

Many years of coal production have led to significant changes in the stability of the rock mass and the earth's surface in the territory of the coal mining regions of Ukraine. The reasons for such changes are the increase of fracture and decrease of the strength of rocks, stratification and hanging of rocks in the boundary parts of workings, the presence of interstices in the coal-face workings, large-scale subsidence of the earth's surface, underworking of a considerable number of buildings, structures and infrastructure.

Rozwiązania technologiczne zwiększające efektywność procesów wzbogacania w eksploatacji złóż tytanowo-cyrkonowych

“…Mined ore in the form of pulp enters the collective concentrate plant, where ore beneficiation and distribution of ore pulp into rough concentrate (up to 7%), clay fraction beneficiation tails (up to 20%), and sand beneficiation tails (up to 72%) take place in parallel. The crude concentrate is transported to a stationary concentrator through a pulp pipeline [12]. The tailings of clay fraction beneficiation are carried through the pulp pipeline to the thickener, which is located in the immediate vicinity of the pit, where the clay is thickened with the subsequent placement of accompanying raw materials in the man-made deposit.…”

Kontrola stabilności zrzutu załadunku skały na krawędzi wyrobiska

“…External dumps of overburden rocks are formed with the formation of safety berms in several tiers [26][27][28]. The height of such dumps rarely exceeds 100-120 m. The horizontal berms and slopes of the tiers of the external dump form a resulting angle of 13-15 degrees to the earth's surface.…”

Determining conditions of using draglines in single-tier internal dump formation

“…The essence of the Slide software is that it builds the section of the calculated array, determines the location of the square in which the centers of radiuses of curved sliding surfaces are placed, then the program finds coefficients by the curved surfaces according to all points of centers and radiuses and points to the smallest indicator. Therefore, to de termine the stability near the equipment, the operator must manually determine the coefficient there [12,13]. The hori zontal scale (X ) corresponds to the distances between the points of slopes and sites on the respective horizons.…”