Therefore, the conventional staggered distance model of ultra-close thin coal seam group during combined mining is put forward; and the theoretical research and physical simulation are carried out.

Based on an example from Datong Coalmines Group, the paper analyses possibility and usage of heavy plow under the conditions of thin seam coal face with Two Hard Roofs and gives out some proposals.

Tectonic group patterns of coal seam depended on tectonic stress field, mechanical properties of rock of coal-bearing formation and surrounding environments.