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

Table 15

Composition of matrix .

Index factor	Threat level
	Safe (I)	Low threat (II)	Medium threat (III)	Relatively high threat (IV)	High threat (V)
	[0.13, 0.69]	[0.41, 0.96]	[0.69, 1.24]	[0.96, 1.52]	[1.24, 1.80]
	[1209.01, 1332.31]	[1270.66, 1393.96]	[1332.31, 1455.61]	[1393.96, 1517.26]	[1455.61, 1578.91]
	[0.90, 1.17]	[1.03, 1.30]	[1.17, 1.43]	[1.30, 1.56]	[1.43, 1.69]
	[15.03, 28.76]	[21.90, 35.63]	[28.76, 42.50]	[35.63, 49.36]	[42.50, 56.23]
	[0, 0.59]	[0.01, 1.16]	[0.59, 1.74]	[1.16, 2.32]	[1.74, 2.89]
	[0.99, 1.23]	[1.11, 1.36]	[1.23, 1.48]	[1.36, 1.60]	[1.48, 1.72]
	[46.19, 51.36]	[48.77, 53.94]	[51.36, 56.52]	[53.94, 59.11]	[56.52, 61.69]
	[-227.07, -128.73]	[-177.90, -79.56]	[-128.73, -30.4]	[-79.56, 18.77]	[-30.4, 67.94]