Researches And Applications On Coal Mine Gas Drainage Technology

Coal mine gas accident is one of the most serious natural disasters in coal mine. It is the long-term constraint on the coal mine safety productive work in China and in the world. Though experts and scholars in both China and abroad carried on intensive research and have made technological breakthroughs into its prevention and treatment, it is still difficult to get the distribution of mine gas and gas migration law, to predict the mine gas emission quantity and set the drilling hole position of gas drainage effectively, due to the many factors that influence mine gas storage, distribution, emission, migration and flow (such as the adsorption constants, coal seam porosity, coal-seam gas pressure, gas permeability of coal seams, coal rank, coal seam thickness, seam depth, the condition of mining fissure, upper rock cover and hydrogeologic condition).This article refers to and summarizes the researches on gas drainage technology from large numbers of relevant documentation and regulations. On the basis of actual situation, by means of the basic theory analysis, mathematical modelling, simulation experiments and in situ measurement etc., the article first analyzes issues like geological storage and distribution characteristics of mine gas, influential factors of gas emission and gas migration law in coal seam. Then mathematical models with continuity and dynamic characteristics are established to predict coal gas emission quantity separate source, that is to predict gas emission quantity of mechanized mining face (that of mind bed and that adjacent seam), to predict gas emission quantity of heading face (that of coal wall and coal cutting), and to predict gas emission quantity of goaf. In the initial stage of coal mine production, the absolute gas emission quantity is predicted as 91.66 m3/min by calculation. Next, by comparing various methods of gas drainage, a technical proposal that the usage of both in-seam gas drainage (gas drainage while driving in heading face and pre-drainage and drainage while extracting in mining face) and goaf gas drainage (fully enclosed drainage of old goaf, high position drilling drainage and the upper corner intubation drainage of goaf) is determined upon, and an integrated technical system of mine gas drainage is established. It is established that the gas drainage quantity of the observed coal mine is around 43.4m~3/min, and its annual drainage quantity is around 20.62Mm~3/a. Last, given that mine gas is a clean energy of low cost and high quality, and the gas drainage quantity is 43.4m~3/min and gas drainage efficiency is about 47.3% in the observed coal mine,which are in line with the standard of Basic Indicators of Mine Gas Drainage (AQ1026-2006),it is confirmed the plan of the industry, civil and electricity generation utilization of gas drainage.