Method for cutting and pre-breaking top coal to improve mining efficiency by utilizing water power

Abstract

The invention relates to a method for cutting and pre-breaking top coal to improve mining efficiency by utilizing water power, which solves the problem that a relatively hard and complete roof coal seam, particularly a coal seam tightly attached to an upper rock body, is difficult for top coal caving, large in coal falling lumpiness and not high in mining efficiency. The method comprises the following steps of: drilling advanced boreholes in a roof coal body to a coal rock boundary surface on a mining working surface by utilizing a drilling machine; extending a high-pressure water pipe in the boreholes; and cutting a plurality of subhorizontal semicircular transverse slots by utilizing the impact force of high-pressure water from top to bottom in the top coal. A plurality of yielding regions are formed by the boreholes in linear distribution in the roof coal body, the mechanical conditions in the coal body are changed, the hard and complete coal body is promoted to be deformed and broken under the effect of advanced concentrated stress, and a plurality of cracks are generated; the coal-rock and coal-coal contact areas are reduced through the transverse slots, and the coal body on the boundary surface is further extruded under the effect of roof high stress, so that the coal body is broken, the adhesive power is lost, manual layering is achieved, and coal is convenient to fall. The method is simple and quick, high in operability and good in timeliness, the coal mining speed can be efficiently increased, and the mining efficiency of the top coal is improved.

Description

technical field [0001] The invention relates to a method for increasing the mining rate of coal, in particular to a method for increasing the mining rate by using hydraulic cutting to pre-break the top coal. Background technique [0002] The top-coal caving mining method has been widely used since it appeared in the 1970s and 1980s, which greatly reduces the labor intensity and improves the working efficiency of coal mining. However, in the application process of this technology, for some coal seams, such as coal seams with relatively hard coal quality and good integrity, there are often problems such as difficulty in completely dropping the top coal, large coal lumps, and low mining rate, resulting in A lot of resources are wasted. Aiming at this problem, domestic and foreign scientific and technological workers have proposed many methods to solve it, such as water injection softening, high-pressure water injection fracturing, deep (shallow) blasting and other methods. Th...

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Problems solved by technology

[0003] Technical problem: The purpose of the present invention is to provide a simple construction and time-effective roof coal seam, especially for the problem of difficulty in caving top coal and low mining rate in the coal seam close to the upper rock mass, which is relatively hard and has good integrity. Coal mining method with good performance, safety and effective improvement of top coal mining rate

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