Evaluation of Water Inrush Risk in Deep Mines Based on Variable Weight and Unascertained Measure Theories and GIS

Table 5

The index risk grade standards.

Index grades	Mining depth (m)	Dip angle of coal seam (°)	Thickness of water-resisting strata (m)	Water pressure (MPa)	Fault intensity index
1	<480.68	<11.5	>53.67	<0.85	<0.11
2	480.68–717.54	11.5–16	39.50–53.67	0.85–2.40	0.11–0.28
3	717.54–942.59	16–22.5	22.50–39.50	2.40–4.70	0.28–0.47
4	>942.59	>22.5	<22.50	>4.70	>0.47