The effects of igneous intrusions on coal-bed macerals, maturity, and adsorption

Coal samples JM, M1-M18 selected around dykes A and B from the Qiwu mine were used to investigate the effects of igneous intrusions on coal-bed macerals. The results of the experiments and calculations show that the vitrinite reflectance of coal samples decreases sharply from 3.4% to 0.72% with increasing distance from dyke A and later remains at 0.8%. There are many thermogenic pores in the micrograph of samples JM, M1, and M5, while the pores of other samples are generally of the fusinite and telinite types. The porosity of sample M5 is 12.99%, and the average pore size is 280 nm, which is greater than that of samples M6-M18, the pore sizes of which range from 3.23% to 4.45% with an average of 17.8 nm. The V-L and P-L for sample M1 are 8.44 m(3)/t and 0.93 MPa, respectively. Based on the change in V-L, which ranges from 7.43 m(3)/t to 8.67 m(3)/t with an average of 8.14 m(3)/t, the research area can be divided into three zones.