Development of recommendations on effective ways of working out the formation in the conditions of its fragmentation and counterfeiting

Abstract

In the article the analysis of an existing way of working off of a layer ℓ1 in the conditions of its overworking and underworking is made. The regularities of rock pressure in the lava of this seam are established, the influence of mining-geological and mining factors on the roof stability is investigated and the zones of formation unloading and zones of harmful influence of rock pressure arising as a result of overworking and underworking are determined. The roof of the formation ℓ1 as a result of overwork and underwork is broken by systems of mutually intersecting cracks; the bearing capacity of the roof of the formation depends on the presence of the main cracks, oriented parallel to the bottom of the face, in the bottomhole space and the distance between them; when the distance between the main cracks is up to 1 m, the roof loses its stability, with increasing distance between the main cracks, the condition of the roof improves; the magnitude of the load on the bottomhole mounting ranges from 7 tons to 19 tons, which indicates the unloading of the seam as a result of overwork and underwork; the increase in the load in the lower part of the lava to 25 tons is caused by the influence of the supporting contours of the upper and lower layers; the magnitude of the lowering of the roof in the lower part of the lava is 4 and 1,5 times higher than in the middle and upper parts of the lava. Recommendations are given to increase the stability of the roof and prevent blockages of formation lavas: the lower part of the lava is exposed to the reference pressure that occurs on the support contours of the treatment workings of formations ℓ2 and k8в; the influence of the reference pressure from the forgery of the formation ℓ1 extends to 60 m after the uprising; the influence of the reference pressure from the superstructure extends to 18 m; the lower part of the bench in the uprising up to 14 m is jointly affected by overwork and underwork; the middle part of the lava undergoes less intense manifestation of rock pressure, because it is in the unloaded area; the influence of the reference pressure arising at the boundaries of the safety pillars on the lower layer extends to 20 m; in the conditions of development of formation ℓ1 leaving of safety pillars of coal on the layers overworking and underworking, it is not expedient; when preparing new rows should take into account the parameters of the reference pressure zones; the location of the lava formation ℓ1 outside the zones of influence of the reference pressure from overwork and underwork should be considered promising.