A top-coal weakening method with three functions in one operation

Abstract

The invention discloses a one-site triple-purpose top coal weakening method which comprises the following steps of S1, dividing a coal body between a conveying gateway and a track gateway into multiple drilling blasting areas; S2, arranging a drill site in top coal at the middle position, close to the gateways, of each drilling blasting area; S3, arranging blasting drill holes in a fan shape by adopting the drill site as an original point in the drill site, wherein the blasting drill holes are inclinedly arranged along a coal bed, and the hole bottoms extend to the boundary positions of the drilling blasting areas on which the holes are formed; S4, reserving partial blasting drill holes as control holes; charging in other blasting drill holes, gradually reducing the charging amount from the hole bottoms to the hole ports, and after sealing the drill holes, adopting a delayed blasting method for blasting; S5, after blasting, carrying out dynamic pressure pulse water injection into control holes, wherein the water injection pressure is 5 to 15MPa; S6, after finishing water injection, arranging gas drainage drill holes in the drill site, enabling the hole bottoms of the gas drainage drill holes to face a goaf, and carrying out gas drainage operation. The one-site triple-purpose top coal weakening method provided by the invention has triple purposes in one site, and the top coal can be effectively weakened, so that the top coal drawing blackness is reduced, and the top coal drawing rate is improved.

Description

technical field [0001] The invention relates to a top-coal weakening method, in particular to a three-purpose top-coal weakening method, which belongs to the field of mining. Background technique [0002] For the mining of thick coal seams, the comprehensive top-coal caving development method is commonly used at present; and for shallow-buried thick coal seams with high toughness and hard top coal, and the basic top is hard sandstone, under normal circumstances, the overlying strata contain more The multi-layered thick and hard key layer leads to weak pressure transmission at structural failure, and the peak bearing pressure is small due to the shallow buried depth. The top coal belongs to the high toughness and hard top coal, which has high compressive and tensile strength, low elastic modulus, low compression-drawing ratio, and large deformation before failure; , leading to the difficulty of breaking, crushing, and release of the top coal in the fully mechanized caving fa...

AI Technical Summary

Problems solved by technology

[0002] For the mining of thick coal seams, the comprehensive top-coal caving development method is commonly used at present; and for shallow-buried thick coal seams with high toughness and hard top coal, and the basic top is hard sandstone, under normal circumstances, the overlying strata contain more Multiple layers of thick and hard key layers lead to weak pressure transmission at structural failure, and the peak bearing pressure is small due to the shallow buried depth

The top coal belongs to the high toughness and hard top coal, which has high compressive and tensile strength, low elastic modulus, low compression-drawing ratio, and large deformation before failure; , leading to the difficulty of breaking, crushing, and release of the top coal in the fully mechanized caving face. Under this condition, the top coal often has a strong impact tendency; The output of noodles is increased, and there is a large potential safety hazard

[0003] In view of the hard top coal, water injection or blasting is generally adopted to weaken the top coal, so as to increase the output of fully mechanized caving and eliminate hidden dangers; however, weakening the large top coal at the support of the working face cannot be used in high gas mines The effect of static pressure water injection on coal seams with low porosity or softening coefficient greater than 0.75 is general, and the effective range of deep hole pre-splitting blasting drilling in fully-mechanized caving face construction is small, and it is impossible to accurately carry out the top-coal inclusion. Blasting, the construction process has a long construction period and it is difficult to implement ventilation and blasting in high-gas mines

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