*2.1. Panel Profile*

Buertai Coal Mine is the largest underground mining coal mine in China with an annual output of 20 Mt. The mine is located in the central part of Dongsheng Coalfield in Ordos City, southern Inner Mongolia Autonomous Region. The mining roadway in Buertai Coal Mine adopts the double-roadway layout mode, i.e., two mining roadways are excavated at the same time, one of which is affected by repeated mining and needs to serve two working faces (called reserved roadways). The geographic location, related photos, and mining layout of the Buertai Coal Mine are shown in Figure 1.

**Figure 1.** Basic overview thumbnail of Buertai Coal Mine.

Comprehensive mechanized top-coal caving is adopted in panel 42107 of coal seam 4-2 in Buertai Coal Mine. The length of the working face is 300 m, the average depth of the coal seam is 457 m, the thickness of the coal seam is 7.6 m, the dip angle of the coal seam is 1~3◦, and the length of the panel is 4808 m. The average distance between coal seam 4-2 and overlying coal seam 2-2 is 75 m. The upper part of the coal seam 4-2 roadway is coal seam 2-2 goaf. There are two key strata in the overlying strata between coal seam 4-2 and coal seam 2-2, which are fine sandstone subcritical stratum 1 with a thickness of 8.6 m and siltstone subcritical stratum 2 with a thickness of 22.6 m. Rock parameters of the roof and floor of 4-2 coal seam are given in Table 1.

**Table 1.** Geological parameters of coal and rock.

