Study on the Technology of Enhancing Permeability by Millisecond Blasting in Sanyuan Coal Mine

Table 6

Gas concentration table.

Time	Gas drainage concentration in borehole (%)
	3#	4#	5#	6#	10#	11#	12#	13#	14#	15#	16#	17#
11–22	38.4	39.7	38.7	37.8	45.4	46.7	47.7	46.8	21.7	22.2	22.1	21.9
11–24	38.3	37.7	37.9	36.8	48.3	48.7	47.9	47.8	20.7	23.0	23.6	20.9
11–26	39.7	36.9	35.6	37.8	46.7	48.9	48.6	48.8	21.0	21.8	21.3	18.7
11–28	38.6	35.4	35.2	36.1	44.6	46.4	46.2	48.1	19.6	20.7	21.0	19.9
11–30	36.2	36.2	36.1	35.3	40.2	43.2	45.1	44.3	18.5	18.7	19.7	20.7
12–02	36.4	35.3	37.5	34.5	42.4	45.3	44.5	42.5	18.6	16.8	18.2	17.2
12–04	33.9	34.2	33.2	36.6	38.9	40.2	42.2	40.6	17.9	18.7	17.9	16.8
12–06	31.8	34.7	32.7	33.9	35.8	38.7	41.7	40.9	18.4	16.5	17.2	17.3
12–08	29.4	31.4	30.2	32.1	37.4	39.4	36.2	36.1	17.9	17.2	18.0	16.9
12–10	31.5	28.3	29.7	32.2	34.5	38.3	38.7	37.2	16.8	16.6	17.6	16.6
12–12	32.2	27.2	30.1	31.3	34.2	37.2	34.1	34.3	15.9	15.9	16.9	15.8
12–14	31.7	27.7	28.3	30.6	35.7	36.7	35.3	35.6	15.6	16.3	15.9	16.0
12–16	30.4	31.5	29.5	27.3	34.4	35.5	33.5	34.3	16.0	15.9	16.7	15.9
12–18	29.1	30.1	30.5	28.0	32.1	32.1	32.5	35.0	15.8	16.5	16.2	16.3
12–20	28.0	28.6	28.4	26.9	32.0	31.6	31.4	30.9	15.7	15.7	16.3	16.4
12–22	27.5	27.1	28.6	27.6	31.5	31.1	33.6	32.6	15.3	15.5	15.9	16.0
12–24	27.7	26.2	27.0	26.9	29.7	32.2	32.0	28.9	15.6	15.6	15.7	15.3
12–26	26.2	25.7	26.5	24.7	29.8	29.7	31.5	30.7	15.3	15.4	15.4	14.9
12–28	25.9	26.6	23.3	26.5	28.9	29.6	30.3	29.5	15.4	15.2	15.5	15.1
12–30	25.8	24.6	23.6	23.4	28.8	29.6	29.6	28.4	15.1	15.0	15.2	14.5