Study on Causes of Gas Abnormal Emission from Limestone Cracking Development Zone

In order to solve gas disasters frequently occurred in coal mines with low gas emission, with the analysis conducted on gas control status of Yitang Coal Industry, the gas geological theory was applied to study the causes of the gas abnormal emission from local seam. The study held that the geological structure role coul d make the strata affected with crumpled broken, thus could make cracking development of the roof limestone and could make a large amount of free state gas stored i n the cracks. In the cracking development zone of the limestone affected by the mining and excavation activities, a centralized emission of free state gas would cause a local gas abnormal emission. Therefore, the paper analyzed the gas generation condition, gas storage condition and gas cap rock condition affected to the gas emissio n quantity.The advance exploration borehole, gas drainage borehole drilled at the seam and seam with roof jointed location, pressure balancing ventilation, increased V entilation of the coal mining face, enhanced management of the mine electric and mechanical equipment and others measures were applied to prevent the coal and gas accident occurred.