Gas Drainage Technology in Fully Mechanized Coal Mining Face in Jiaojiazhai Mine

According to the gas content over the limit problems at the top corner and the tail head of the rear scraper conveyor of the coal mining face in Jiaojiazhai Mine,the gas drainage with the pipeline buried at the top corner,the gas drainage with slanting crossed boreholes in mining seam and the gas drainage with high level crack boreholes along roof strike were applied.The comparison on the three gas drainage methods was conducted.The results showed that the measures of the gas drainage with pipeline buried at the top corner would require small construction quantity,but the drainage rate was lower(5%).The gas drainage rate of the gas drainage with slanting crossed boreholes in mining seam though would be higher(15%~20%),but the construction quantity would be high.From the comparisons,the gas drainage rate of the gas drainage with high level crack boreholes along roof strike could be over 30% and the gas drainage method could drain the high content gas from the caving zone and the crack zone of the goaf.Thus the ventilation quantity could be reduced for the gas drainage and the safety production of the coal mining face could be ensured.