Research on air leakage characteristics in goaf of working face under natural wind pressure

Taking +450 m level B1+2 coal seam working face in the southern area of Wudong Coal Mine as an example, the law of natural wind pressure change is analyzed, combined with the field measured data of air volume changes in the air intake roadway, the actual impact of natural wind pressure on the working face is qualitatively explained. Air leakage amount and distribution are indirectly estimated by calculating projected area of wind speed, and the air leakage phenomenon in the goaf behind the working face caused by change of natural wind pressure is quantitatively studied combined with field measurement and curve fitting methods. Research result shows that the change of natural wind pressure in the southern area of Wudong Coal Mine has significant impact on branches in the ventilation system and the main ventilator operating points of the mine; the change of natural wind pressure is the main controlling factors that affects the change of air volume in the air intake roadway of B1+2 working face; In winter, due to the high natural wind pressure, the air volume in the air intake roadway becomes larger, the air amount leaking into the goaf is more than that in summer, the air flow velocity in the goaf is faster, and the flow field distribution range in the goaf is wider.