Study on goaf gas drainage technology and float coal spontaneous combustion coupling control

In order to solve the coupling governance problem of coal spontaneous combustion and gas overrun in gob of Ximing coal mine, a heterogeneous porous media 3D model and simulation were applied to set up the comprehensive fire prevention and control technical plan and to conduct the site monitoring and measuring W ith the measures of the high level gas drainage gateway and in comparison with the change conditions of the air velocity flow field, gas concentration field and oxygen C oncentration field in the goaf before and after the two sides of the air intake and air retuning gateways sealed in the goaf. The results showed that the gas drainage met hod with the high level gas drainage gateway was applied to seal the air retuning gateway and the transportation gateway and thus the air leakage of the coal mining fa ce to the goaf was reduced.The width of oxidized strip was reduced by 6 m, the gas drainage volume faction of the high level drainage gateway was increased by 4.1 2% and the gas drainage efficiency was improved. The site monitoring and measuring showed that the gas drainage flow volume of the high level gas drainage gateway was 19.18 ~ 20.57 m3/min, the gas drainage flow volume with the pipe buried at the top corner was 10.16 ~ 11.32 m3/min and thus great gas emission from the goaf an d the gas overlimit phenomenon at the top corner were eliminated. With the implementation of the inhibitor agent sprayed, nitrogen injection and other measures, the 0X idation phenomenon of the coal left in the goaf of No.48205 coal mining face was effectively controlled and the safety production of the coal mining face was ensured.