Figure 6

The Working Face’s simulation distribution of the gas concentration in the South Wu-1201 during mining. Figure 6 illustrates the simulation distribution of the gas concentration during the period of the mining. The gas concentration in the goaf gradually increases with the route of air intake. Due to the intensity of larger air leakage, the gas concentration would be small near the roadway of air intake. Under the retaining mining mode of gob-side entry with both roof cutting and pressure relief, the range of air leakage would be wider, and the intensity would be greater due to the open goaf space. Most of the air leakage flows from the retaining roadway to the goaf. The gas concentration in the deeper part of the goaf and the upper corner of the working face reaches 17.82% and 4.64% respectively. It is necessary to use gas control as the target.