Roof Failure Mechanism of Thin Bedrock Working Faces under Loading and Analysis Based on Microseismic Monitoring Technology

Table 2

Roof strata of the coal seam.

Roof type	Lithology	Thickness range (m)
		Average thickness (m)
Upper hard roof	Medium sandstone	2.1–12.3
		7.2
Immediate roof	Sandy mudstone	5.3～21.7
		13.5
False roof	Mudstone	0.2～1.4
		0.8