Method for treating hanging arch through medium-length hole blasting

Abstract

The invention belongs to the technical field of mining, and particularly relates to a method for treating a hanging arch through medium-length hole blasting. The method comprises the following steps: forming a first row, a second row and a third row of medium-length holes in sequence in the top rock stratum of a mining roadway from a hanging arch area into the mining roadway, wherein each row of medium-length holes is distributed in a sector form, thereby forming sector-shaped medium-length holes; the distribution surface angle of the first row of medium-length holes is 60 degrees; the distribution surface angle of the second row of medium-length holes is 70 degrees; the distribution surface angle of the third row of medium-length holes is 90 degrees; and the first row and second row of medium-length holes extend to the hanging arch area; filling explosives and millisecond delay detonator tubes into the medium-length holes, and detonating the explosives to break the hanging arch. Compared with the conventional method, the method has the advantages that the ore loss rate is lowered from 60 to 70 percent to 6 to 9 percent, the mining recovery rate is increased greatly from 30 to 40 percent to 91 to 94 percent, and the operation safety is ensured.

Description

technical field [0001] The invention belongs to the technical field of mining, and in particular relates to a method for treating suspended roofs by medium and deep hole blasting. Background technique [0002] The segmental caving mining method, the stage height is 50-60 meters, the segmental height is 10-12 meters, and the mining approach distance is 10-11 meters. During the mining process, with the release of caving ore in this section, the waste rock covering layer in the upper section is released accordingly. When the ore drawing is completed, the caving area is full of waste rock covering layer. Suspended roof is a phenomenon in which the caving height of this subsection does not reach the position of the upper subsection, and the uncollapsed part of the ore rock forms a shape similar to a floor, which cuts off the waste rock covering layer of the upper subsection and cannot fill the collapsed area; Due to the design and construction of medium and deep holes are not in...

AI Technical Summary

Problems solved by technology

[0003] After the suspended roof appears, the traditional method is to mine ore in the small empty field formed after the suspended roof. In order to prevent the roof of the open field from collapsing and ensure safe production, most of the collapsed ore is left in the small empty field. A small amount of ore can be mined, and the middle and deep hole blasting and ore extraction in the back row are continued, resulting in a mining loss rate of up to 60-70%, and a mining recovery rate of only 30-40%. Stable, there is a possibility of collapse and fall at any time, which will cause harm to safety production and cannot meet the needs of mine safety production

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