Optimization Research Of Gas Pre-drainage Parameters In Jiangjiahe Mine

Gas pre-drainage has become an indispensable and important part of coal mine safety production.However,in the actual extraction process,many mines still face the problem that the original coal seam is difficult to draw and the gas extraction rate is low.Jiangjiahe Coal Mine belongs to the high-gas coal mine.With coal mining entering the second mining area,the amount of gas emitted from the mining face increases sharply,and the widespread problem is low gas extraction rate at the period of gas drainage by drilling.In order to eliminate security risks and improve the gas drainage effect of the face,it is decided to carry out a systematical scientific research on gas drainage work in the second mining area.It is the premise of optimizing the effect of the pre-drainage effect of borehole to determine the main influencing factors of mine gas pre-drainage.This paper uses Analytic Hierarchy Process to analyze the influencing factors of the pre-drainage effect of borehole,to build and evaluate multi-level structure model about Jiangjiahe Coal Mine the pre-drainage effect of borehole.The evaluation results show that the main influencing factors of borehole pre-drainage of gas effect of Jiangjiahe Coal Mine are drilling distance,penetration measures and drilling diameter.Other factors are less affected.Penetration measures are limited by the actual situation,and the optimization factors are drilling distance and drilling diameter.With a combination of theoretical analysis and field testing,comprehensive comparison of drilling area of different borehole drilling,coal exposed area,extraction effect of drilling,drilling speed and equipment cost,the drilling diameter of the second mining areas in Jiangjiahe Coal Mine is 113 mm.At the same time,it revealed the influence that existed between the adjacent drilling superimposed drainage.During the extraction period,the drilling distance increase 0.6-1.6 m of effective drainage radius than double drilling,moreover,the longer the pumping time,the smaller the increasing.Field application results show that the optimization of hole spacing and hole diameter can greatly improve the gas extraction rate,solve the problem of low gas extraction rate in the second mining area and it tests the feasibility of using the analytic hierarchy process to evaluate the effect of borehole pre-drainage gas and the accuracy of the evaluation model and evaluation results.The paper uses the Analytic Hierarchy Process to find the main effect factors of borehole pre-drainage of gas in Jiangjiahe Coal Mine,and the method is systematic,scientific,easy to use,and has high sensitivity.It has high promotion value in the process of evaluating the influence of the gas extraction effect on the pre-drilling gas drainage in other mines.Using the field test to get the optimized results,the arrangement of the test program and the result analysis are reasonable and the obtained results are reliable.It is of great certain guiding significance and practical reference value to select the drilling diameter and measure the drilling distance for other mines,and extraction design of the continuous face in the second mining Area of Jiangjiahe Coal Mine.