Gob-side entry retaining Y-type ventilation high-position return airway drilling gas extracting method

Abstract

A gob-side entry retaining Y-type ventilation high-position return airway drilling gas extracting method includes: constructing connecting roadways at intervals between a rail roadway top pumping roadway and a rail roadway; building a filling wall along the edge of a gob during extraction to retain the rail roadway, allowing a transportation roadway and the rail roadway to perform work face air intaking and a rail roadway retained roadway section, the connecting roadways and the rail roadway top pumping roadway to perform air returning so as to form a gob-side entry retaining Y-type ventilation system, and secondarily using the rail roadway top pumping roadway as the high-position air returning roadway; performing gas extracting drilling on adjacent coal beds and gobs in the high-position air returning roadway, and extracting gas. By the method, the drilling requirements on retaining roadway section can be lowered, mutual interference of drilling and work face extraction, and construction management is facilitated. Due to the fact that the high-position air returning roadway is far away from the work face mining motion influence, the mining motion interference on drilling is lower than front and rear drilling of the retained roadway, easy drilling maintenance is achieved, and efficient and long-term gas extraction can be achieved.

Description

technical field [0001] The invention relates to a coal mine gas extraction method, in particular to a method for drilling gas extraction in a gob-side entry Y-shaped ventilation high-position return airway suitable for safe mining of high-gas coal seam groups in deep wells. Background technique [0002] As a clean energy, gas should be mined and utilized. However, the occurrence of coalbed methane in most coal mining areas in my country has the characteristics of "three lows and one strong" of low pressure, low permeability, low saturation and strong heterogeneity. Coal and rock roadways use roadway + cross-layer drilling for gas extraction (referred to as roadway drilling method). This method is easy to implement in shallow mining, but it faces great difficulties in deep application: dedicated rock roadway for gas drainage (2-3 Article) Large amount of engineering, difficult layer control, high risk of excavation, unbalanced extraction, tense replacement of stopes, and poor ...

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Problems solved by technology

[0004] However, due to the large amount of deformation of the roadway in the gob-side entry retaining project of deep well and high ground pressure, especially the bottom heaving of the roadway, in order to control the deformation of the surrounding rock of the roadway, it is usually necessary to erect support components such as wooden piles and single hydraulic props in the roadway retention. It cannot meet the cross-section size requirements of drilling construction; at the same time, because the drill holes arranged in the retaining entry are close to the edge of the goaf, the disturbance effect of mining is strong, and the drilling is prone to cutting and plugging, and the gas drainage effect is difficult. ensure

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