Fig. 1

Schematic diagram of coal seam mining in karst areas (a) Karst landform in northern Guizhou; (b) The shape of the sinkhole on-site survey in northern Guizhou; (c) Conical funnel-shaped karst on-site survey; (d) a conical funnel-shaped cross-section formed by dissolution of vertical cracks in water flow rock (P3c = Changxing Formation; T1y = Yulong Formation).