Layered mining method for ultra-thick coal seam containing dirt band layer in middle

Abstract

The invention discloses a layered mining method for an ultra-thick coal seam containing a dirt band layer in the middle, and belongs to the technical field of efficient mining of ultra-thick coal seams. The layered mining method comprises the four steps including layer dividing, first layer mining, second layer mining and bottom layer mining. During layer dividing, with the starting point of the high efficiency and the high recovery rate and the principle of reducing the mining disturbance influence, the layering positions and thicknesses are determined according to the broken-expansion coefficient of coal mass and the coal drawing height; a first layer is subjected to full-mechanized caving mining, and a metal net is laid at the bottom of a work face; a second layer is subjected to full-mechanized caving mining, and a goaf is filled maximally by utilizing the loose broken-expansion characteristics of the dirt band layer and the coal mass with a certain thickness on the upper part andthe lower part of the dirt band layer; and during bottom layer mining, all the coal mass subjected to broken-expansion is drawn at a time. According to the layered mining method, disturbance of layered mining of the ultra-thick coal seam on an overlying rock stratum can be reduced, middle dirt band and the coal mass near the dirt band are broken through two times of mining, thus drawing is easy, and the recovery rate can be increased effectively.

Description

technical field [0001] The invention belongs to the technical field of high-efficiency mining of extremely thick coal seams, and is mainly applied to layered top-coal caving mining of extremely thick coal seams. Specifically, it is a layered mining method of a 45-55m extremely thick coal seam containing gangue in the middle. Background technique [0002] my country is the largest coal-producing country in the world. The reserves and output of extremely thick coal seams account for a large proportion of the national coal production. Northwest my country has large reserves of coal resources, shallow buried depths, and thick coal seams, which have good mining prospects. Efficient mining of extremely thick coal seams is crucial to increasing my country's coal production. [0003] In recent years, for the mining of extremely thick coal seams, the commonly used methods in my country mainly include layered fully mechanized mining, layered fully mechanized caving, and large mining ...

AI Technical Summary

Problems solved by technology

For the 45-55m thick coal seam with gangue in the middle, the commonly used mining methods have a great impact on the disturbance of the overlying rock, and the recovery rate is relatively low, which is difficult to meet the production requirements of high efficiency and high recovery rate

There are two main reasons for this problem. On the one hand, the gangue layer in the middle of the coal seam will seriously affect the discharge of the top coal, resulting in poor caving performance of the top coal and lower recovery rate; on the other hand, due to the limitation of the current mining technology ( The thickness of the coal seam is limited in one-time mining), resulting in some coal resources being stranded in the goaf, and the loss of coal loss is serious

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