Isolated-section grouting filling coal-mining method for mining overburden rock

Abstract

The invention discloses an isolated-section grouting filling coal-mining method for mining overburden rock, which comprises the following steps of: dividing the mining area into a plurality of coal faces, arranging isolation coal pillars among the coal faces; drilling a plurality of groups of inlet wells above the plurality of coal faces towards a coal bed direction, wherein each group of inlet wells are provided with a primary inlet well and a secondary inlet well, and the final hole depth of the primary inlet well is 15-40 times higher than the coal bed mining height above the coal bed; the final hole depth of the secondary inlet well is located at 30-50m place above the final hole depth of the primary inlet well; and when the coal face is mined to 10-30m from the primary or secondary inlet well, injecting coal ash slurry in abscission zones in the rock strata above the coal face until finishing isolated-section grouting filling coal mining in the mining area. The method is fit for coal mining under buildings with a high recovery ratio, small interference to filling and coal mining, low filling cost and good control effect to sink, and can facilitate coal mining without village migration under sufficient mining conditions.

Description

technical field [0001] The invention relates to a coal mining subsidence control method, in particular to a coal mining method suitable for mining overlying rocks under buildings in isolation, grouting and filling. Background technique [0002] Coal mining under buildings has always been a major problem plaguing my country's coal mining enterprises, especially coal mining under villages. With the gradual depletion of resources in some mining areas, the problem of coal pressing in villages has become more and more prominent; especially in areas with relatively developed economies, due to the shortage of land resources and the increase in relocation costs, it is imperative to press coal without relocating mining buildings. The successful mining of compressed coal in buildings (villages) is of great significance to improving the utilization rate of coal resources and alleviating the tension of mine resources. [0003] Traditional solutions to the problem of coal pressure under...

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Problems solved by technology

Although the method of leaving protective coal pillars can solve the problem of surface subsidence, it cannot recover the coal pressed under the building, resulting in a large amount of coal loss; the disadvantages of strip mining are low recovery rate (generally less than 50%), serious waste of resources, and roadway excavation. High production rate and low production efficiency restrict the high-yield and high-efficiency development of coal mines; the traditional layer-separated grouting filling has a better subsidence reduction effect only when the mining area is not fully mined (that is, the size of the mining area is small). The ideal subsidence rate is obtained du

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