"Y + High Pumping Lane" Working Face Research And Application Of Gas Control Technology In Early Mining Period

The 3# coal mined by Zhangcun Coal Mine of Lu’an Group is a single high-gas coal seam.There was an abnormal gas gushing problem at the first pressure,which seriously threatened the safe mining of the working face.The gas problem in the initial mining face of the working face is caused by the sudden collapse of the large area of the hard roof and the sudden collapse of the high concentration gas accumulated in the goaf.However,the rock layer of the high-drainage roadway in the initial mining period has not entered the fissure zone,and it is difficult to collect gas in the mined-out goaf area,and cannot play the role of the high-drainage roadway to control gas.Only by increasing the amount of air to discharge gas,the ability to control gas is limited,and at the same time,the air leakage in the goaf is serious.This article starts with weakening the roof,combined with the improvement of high-drainage roadway,increased ventilation and coal seam gas extraction,to achieve the purpose of comprehensive gas control in the initial mining period.The main results are as follows:1)Before each face is mined,the roof must be weakened.Through field investigation,the pre-splitting blasting hole spacing was optimized to 6m and the charge length was between 9 ~ 13.2m.The roof of 2603 working face was weakened.The pre-crack effect of the roof was investigated through the established mine pressure monitoring system.It was found that the pre-cracked 2603 working face roof was easier to collapse than the 2601 working face,and the pressure step was shorter than the 2601 working face,and the effect was good.2)Based on the principle of gas interception in high-drainage lanes,determine the relationship between the high-drainage lanes and the main objectives of governance: the high-drainage in high-drainage lanes is mainly drainage,and the pressure relief gas in the upper layer of the interception when pressure comes The low-level high-draining roadway mainly prevents a large amount of pressure-relief gas in the goaf from entering the working face,causing the upper corner gas to exceed the limit.Through the calculation of the fracture zone height and on-site inspection,the high extraction roadway is arranged in the lower half of the fracture zone,and a large amount of pressure relief gas is mainly extracted from the goaf area;During the period when the roof span falls,the pressure relief gas is affected by the high pumping lane as soon as possible;at the same time,three drill fields are set up in the cut-out to drill upwards and penetrate the high pumping lane.Finally,through numerical simulation and comparison with the gas drainage volume of 2601 high-drainage roadway,the gas drainage effect of the high-drainage roadway in the initial mining period was verified.3)Through the analysis of the monitoring data of the mine pressure and gas in the return air lane,the variation law of the mine pressure and gas emission is obtained: when the roof and the old roof collapse directly,a large amount of gas will be emitted from the goaf,and the amount of emission is usually The gas emission is 4 ~ 5 times and has a certain hysteresis.According to the monitoring of the supporting stress of the coal body in front of the working face,the scope of the pressure relief area,stress concentration area and original stress area of the front coal body is analyzed and determined.Through the actual measurement of the amount of cuttings and gas emission,it is found that the more the amount of cuttings,the greater the amount of gas emission;and the amount of cuttings is affected by the pressure,the greater the pressure,the greater the amount of cuttings,which shows that The coal seam gas drainage effect will be better.4)Through on-site inspection of the coal seam extraction,high extraction roadway gas extraction and air exhaust gas of the 2603 working face and analysis of its changing rules,it is composed of high extraction roadways with Y-shaped ventilation,increased air volume,roof weakening and improved layout.The comprehensive gas control technology system in the initial mining period of the working face has a good effect,which fully meets the purpose of gas control in the initial mining period of the Zhangcun coal mine working face.The paper has 58 figures,12 tables,and 71 references.