Extraction method adopting deep-hole presplitting blasting along seam floor for coal roadway driving

Abstract

The invention provides an extraction method adopting deep-hole presplitting blasting along a seam floor for coal roadway driving and relates to a blasting extraction method. The extraction method is characterized by comprising the following steps: a gas extraction hole is constructed in front of a to-be-driven coal roadway in a coal seam tunneling direction for gas extraction, then a blast hole parallel to the seam floor is constructed along a floor stratum below coal seam tunneling working face, charging and detonation are performed, and coal seam tunneling is started after gas residue content of a coal seam is qualified; after tunneling to a non-blast area, the blasting extraction work is repeated, and blasting extraction and tunneling are performed alternately. With adoption of the method, the coal seam gas extraction efficiency is high, the extraction cost is low, construction is safe and reliable, coal seam tunneling and blasting extraction are performed alternately, special construction of a floor roadway and an extraction hole across coal strata is not needed, the cost is reduced substantially, and better social and economic benefits can be produced.

Description

technical field [0001] The invention relates to a blasting extraction method, in particular to a coal roadway excavation along a coal seam bottom plate deep hole pre-splitting blasting extraction method. Background technique [0002] The gas geological conditions of my country's coal mines are relatively complex, among which high-gas coal seams account for 50%-70%, and low-permeability coal seams account for about 70% of them. For physical adsorption and chemical adsorption, the gas content in the coal seam exceeds 10m 3 / t, the pressure generated can reach 4-6MPa, and the danger of coal and gas outburst is prone to occur. Therefore, coal mines regard gas prevention and control as the top priority of coal mine safety work. [0003] In the existing coal roadway excavation, in order to extract gas and prevent coal and gas from protruding, first construct a floor rock roadway parallel to the coal roadway to be excavated at 12-24m below the coal roadway to be excavated, and then...

AI Technical Summary

Problems solved by technology

The main problems of this extraction method are: (1) In order to extract gas from the coal roadway to be excavated, a floor rock roadway parallel to the coal roadway to be excavated needs to be constructed under it, and the construction and maintenance costs are high; (2) ) to drill gas drainage boreholes from the floor rock roadway to the overlying coal seam, the length of the drainage hole passing through the rock of the coal seam floor is longer, and the length of the borehole passing through the coal accounts for about 15% of the total length of the borehole, resulting in (3) There are not only a large number of drainage boreholes, but also a small extraction radius in the coal seam. Generally, the extraction time is about one year to meet the requirements of coal roadway excavation, and the extraction efficiency is extremely low. The required extraction period is long

(3) Even if hydraulic fracturing is adopted, CO injection 2 Due to the small drainage radius, it is difficult to improve the drainage efficiency

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