Thick-Anchored Dual-Layer Locking Supporting Technique in Gob-Side Entry Driving with the Narrow Pillar: A Case Study

Table 1

Lithology of the study site.

Lithology	Thickness (m)	Depth (m)	Remarks
Sandstone	50	416	Overlying strata
Sandy mudstone	31	447	Key stratum
Siltstone	11	458	Overlying strata
Fine sandstone	14	472	Key stratum
Siltstone	8	480	Main roof
Sandy mudstone	6.8	486.8	Immediate roof
4^-1 coal	3.2	490.0	Coal
Fine sandstone	6	496.0	Immediate floor
Sandstone	20	516.0	Main floor