Influence Factors’ Analysis of the Face-End Roof Leaks Exposed to Repeated Mining Based on Multiple Linear Regression

Table 6

The mechanical parameters of joints.

Category	Jkn (MPa)	Jks (MPa)	Jfri (°)	Jcoh (MPa)	Jten (MPa)
Sandstone	6368	5840	25	3.12	2.08
Medium sandstone	5500	5960	22	2.38	1.56
Siltstone	4540	4800	19	1.85	0.86
Fine sandstone	3600	4380	18	1.27	0.75
Mudstone	2550	2240	17	0.86	0.22
Coal	2350	2320	15	0.45	0.04