Determination of protection range of mining upper protective layers and its numerical simulation
Aiming at the limitation of the traditional method for determination of protection region, combined with the actual situation of a mine, a new method for determination of protection region was put forward (including the protection of working face layout and development direction), that is, gas flow observation analysis on the spot and gas content contrast method. The protection region was determined by gas flow observation analysis, gas content contrast, and computer numerical simulation combined with engineering practice. In the process of gas content test, the fixed sampling method “big hole drill reaming, small orifice drill rod connected with core tube” was employed. The results show that the determined protection region is in accordance with the actual site situation. The fixed sampling method ensures the accuracy of gas measurement of gas content.