Effects of Igneous Intrusion on Microporosity and Gas Adsorption Capacity of Coals in the Haizi Mine, China

Table 2

Pore characteristics, adsorptive capacity, and initial gas-releasing rates of coal samples.

Sample	Units	Number 1	Number 2	Number 3	Number 4	Number 5	Number 6	Number 7	Number 8	Number 9	Number 10	Number 11	Number 12
Distance from sill	(m)	60	70	80	90	100	110	120	130	140	160	180	200
BET surface area	(m^2/g)	2.2	2.8	2.8	3.4	3.6	4.2	3.4	3.6	2.4	1.7	1.4	1.5
D-R micr. surface area	(m^2/g)	21.9	23.5	25.2	36.4	34.7	35.6	32.5	31.7	33.8	18.1	19.3	17.8
D-A micropore volume	(cm^3/g)	0.0079	0.0082	0.0095	0.0146	0.0121	0.0131	0.0138	0.0111	0.0153	0.0088	0.0067	0.0054
Avg. micropore size	(nm)	1.21	1.23	1.24	1.33	1.29	1.31	1.26	1.25	1.27	1.19	1.22	1.18
𝑓		0.42	0.40	0.38	0.22	0.25	0.30	0.29	0.26	0.21	0.17	0.12	0.16
Δ𝑃	(mmHg)	48	43	34	32	34	31	28	31	30	26	21	19
𝑉𝐿	(m^3/t)	37.0	34.2	33.1	35.8	29.9	36.5	31.1	34.7	31.7	26.2	24.6	26.1
𝑃𝐿	(kPa)	957	808	796	732	1217	822	998	1412	1179	828	1519	812

Note: micropores are pores <2 nm; 𝑓: coal firmness coefficient; Δ𝑃: initial gas-releasing rate; 𝑉_𝐿: Langmuir volume; 𝑃_𝐿: Langmuir pressure (daf basis).