A Case Study of Damage Energy Analysis and an Early Warning by Microseismic Monitoring for Large Area Roof Caving in Shallow Depth Seams

Table 1

Stratigraphic column of Shigetai mine.

Stratigraphic order	Lithology	Average thickness/m	Depth/m	Lithological column
1	Aeolian sand	18.1	18.1
2	Packsand	15.9	34
3	Siltstone	16.2	50.2
4	Packsand	12.7	62.9
5	Medium granular sandstone	6.1	69
6	Packsand	8.2	77.2
7	2-2 coal seam	4.1	81.3
8	Siltstone	12	93.3
9	Medium granular sandstone	16	109.3
10	Sandy mudstone	8	117.3
11	3-1 coal seam	4	121.3
12	Siltstone	7.6	128.9