Constant-Resistance, Rigid, and Flexible Coupling Support Technology for Soft Rock Entrances in Deep Coal Mines:A Case Study in China

Table 1

Whole-rock mineral X-ray diffraction analysis.

Number	Sample number	Mineral type and content (%)							Total clay mineralcontent (%)
		Quartz	Potash feldspar	Sodium feldspar	Plagioclase	Calcite	Dolomite	Pyrite
1	Medium-grain sandstone	22.8	—	27.1	—	29.4	—	—	20.7
2	Mudstone	14.5	7.7	10.7	—	—	44.3	3.4	19.4
3	Sandy mudstone	32.9	—	24.7	—	0.4	—	—	42.0