Effect Of Borehole Spraying On The Continuous Flow Method Coal Lane Outburst Prediction Device And The Preventive Measures

Continuous flow method coal lane outburst prediction device as an important new technology in predicting coal roadway outburst hazard,whether or not it could work stably and reliably is related to the normal working face advance and the personal safety in the coal mine. While in the process of simulation experiment which use continuous flow method coal lane outburst prediction device to predict coal roadway heading face outburst risk, there is a problem that when borehole spraying happens,gas carrying large amount of slack would enter filter funnel and cause it blocking.This will cause borehole gas flow which flow sensors have measured is far less than the actual value,and result in that continuous flow method coal lane outburst prediction device can not predict the outburst risk in front of the coal roadway heading face accurately.To solve this problem,the paper has begun with studying the mechanism of borehole spraying and the working principle of continuous flow method prediction device,has analyzed the reason and influence of gas channel blocking caused by borehole spraying,and has put forward some corresponding preventive measures from the drilling process control and equipment improvement two aspects.and finally it has verified the reliability and validity of preventive measures by simulation experiments.The paper study concluded that: there are a variety of factors that cause borehole spraying such as geostress,gas pressure and drilling disturbance,etc;adopting measures like controlling drilling rate and speed,deceasing the diameter of drill bit can reduce the drilling disturbance,thus the occurrence probability of borehole spraying could also be reduced;By adding a contact sensor alarm device and a clean coal rotary rod in the continuous flow method coal lane outburst prediction device, when borehole spraying causes filter funnel blocking,the contact sensor will send out a warning, then the operators temporarily stop drilling immediately and use the clean coal rotary rod to clean up the slack quickly,these measures effectively solve the problem of the filter funnel blocking caused by borehole spraying,so as to ensure the accuracy and reliability of the prediction of the continuous flow method coal lane outburst prediction device.