Quantitative Evaluation for the Threat Degree of a Thermal Reservoir to Deep Coal Mining

Table 14

Composition of matrix .

Index factor	Threat level
	Safe (I)	Low threat (II)	Medium threat (III)	Relatively high threat (IV)	High threat (V)
	[0.27, 0.55]	[0.55, 0.82]	[0.82, 1.10]	[1.10, 1.38]	[1.38, 1.66]
	[1239.83, 1301.48]	[1301.48, 1363.13]	[1363.13, 1424.78]	[1424.78, 1486.43]	[1486.43, 1548.08]
	[0.97, 1.10]	[1.10, 1.23]	[1.23, 1.36]	[1.36, 1.49]	[1.49, 1.63]
	[18.46, 25.33]	[25.33, 32.20]	[32.20, 39.06]	[39.06, 45.93]	[45.93, 52.80]
	[0, 0.30]	[0.3, 0.88]	[0.88, 1.45]	[1.45, 2.03]	[2.03, 2.60]
	[1.05, 1.17]	[1.17, 1.30]	[1.30, 1.42]	[1.42, 1.54]	[1.54, 1.66]
	[47.48, 50.06]	[50.06, 52.65]	[52.65, 55.23]	[55.23, 57.82]	[57.82, 60.40]
	[-202.48, -153.31]	[-153.31, -104.15]	[-104.15, -54.98]	[-54.98, -5.81]	[-5.81, 43.35]