Effects of igneous intrusions on texture and quality of coal seam in eastern Henan Province

To guide reasonable deployment and efficient production for coal mine in eastern region of Henan Province, based on the comprehensive analysis and comparative study of a large number of drilling and test data, this paper explores the basic features of magmatic activities and their influence on the coal texture and coal quality in eastern region of Henan Province. The result shows that magmatic activities during middle-late stage of Yanshan period has effected the texture and the continuity of coal seams, causing the thinning, bifurcate and pinch-out of coal seams in the eastern region of Henan. Moreover, magmatic activities led to the general increase in metamorphic grade of coal seams, and the change of coal quality parameters. The main control factors influencing coal texture and coal metamorphism degree include the primitive occurrence state of coal seams, the initial temperature and the thickness as well as styles of the magmatic intrusion, the distance of the magmatic intrusion from coal seam, surrounding rock mass and lithology of overlying strata.