Influence of Valleys Terrain on Pressure of Fully Mechanized Working Faces in Shallow Coal Seams

Table 1

Pressure features in the working faces of different terrain areas.

Geomorphic type	Pressure step/m	Pressure step average/m	Continuous length of incoming pressure/m	Average value of continuous length of incoming pressure/m	Maximum working resistance/kN	Maximum shrinkage under active column/mm	Maximum wall depth/m	Maximum ceiling height/m
Downhill	5.2–17.6	9.5	0.8–6.6	3.2	11,591	<50	<0.8	<0.5
Uphill	6.2–15.6	9.6	1.6–8.0	3.9	13,364	<1000	<2	<2
Flat	5.4–24.0	11	2.4–4.8	3.7	11,318	<12	<0.5	<0.5