Critical Conditions and Energy Transfer Characteristics of the Failure Process of Coal-Rock Combination Systems in Deep Mines

Table 1

Experimental design.

Set A: samples with different lithologies				Set B: samples with different height ratios
Coarse sandstone-coal	A11	A12	A13	Siltstone-coal height ratio 1 : 1	B11	B12	B13
Fine sandstone-coal	A21	A22	A23	Siltstone-coal height ratio 1.5 : 1	B21	B22	B23
Siltstone-coal	A31	A32	A33	Siltstone-coal height ratio 2 : 1	B31	B32	B33