Height of the Fractured Zone in Coal Mining under Extra-Thick Coal Seam Geological Conditions

Table 1

Characteristics of overlying strata.

No.	Lithology	Elastic modulus (GPa)	Tensile strength (MPa)	Bulk force (kN/m^3)	Thickness (m)
1	Sandy mudstone	18.35	5.47	26.31	3.2
2	K3 sandstone	36.21	7.68	25.44	5.3
3	Medium sandstone	29.57	6.14	26.73	7.7
4	Fine sandstone	35.54	7.81	27.12	2.1
5	Siltstone	23.64	4.97	26.45	5.3
6	4 coal	4.20	1.27	10.36	2.1
7	Siltstone	23.35	4.25	25.78	2.4
8	Kernstone	20.32	4.82	24.21	4.3
9	Fine sandstone	35.62	8.20	25.62	14.8
10	Conglomerate	28.43	4.34	27.35	12.9
11	Kernstone	19.98	5.24	23.89	3.5
12	Conglomerate	28.74	4.34	27.10	12.0
13	Medium sandstone	29.62	7.01	25.52	13.7
14	Siltstone	23.48	4.45	24.58	3.2
15	Fine sandstone	35.21	7.93	27.17	10.7
16	Conglomerate	28.64	4.23	26.95	4.6
17	Fine sandstone	36.01	7.87	26.51	10.3
18	Siltstone	23.17	4.52	25.20	10.5
19	Sandy mudstone	18.46	5.81	25.98	6.9
20	Conglomerate	28.42	3.92	27.15	5.1
21	Sandy mudstone	18.56	4.14	26.51	2.9
22	Fine sandstone	36.12	8.11	26.82	10.7
23	Kernstone	21.31	5.34	25.24	14.3
24	Fine sandstone	35.87	8.64	27.54	6.2
25	Kernstone	20.12	5.42	25.37	25.4