Mechanism and Evolution Control of Wide Coal Pillar Bursts in Multithick Key Strata

Table 1

Strata distribution above 3–1 coal seam.

No.	Lithology	Thickness (m)	Distance to coal seam (m)	Discrimination
1	Fine sandstone	16.3	12.9	SKS1
2	Coarse sandstone	31.0	38.8	SKS2
3	Medium sandstone	28.9	69.8
4	Fine sandstone	18.2	112.2
5	Siltstone	21.4	138.4	SKS2
6	Siltstone	19.6	167.0
7	Medium sandstone	11.4	186.7