Abstract: In order to solve the support problem of roadway locating in the lower seam of contiguous coal seams, this paper, taking Beiyu coalmine in Pu County, Shanxi Province as a case, has studied the stress field in the floor of gob belonging to upper seam and characteristics of deformation and instability for roadway locating in lower seam by means of numerical simulation. Principles of ground control for roadway roof in lower seam have been determined and different roof control methods have been tested in field. According to this research, three-dimensional combined roof control techniques based on hy- draulic expansion bolt and advancing insertion of tube on roof have been put forward with corre- sponding key parameters being determined through theoretical analysis and field test. Field test has suggested that control techniques raised in this paper are effective for the ground control of roadway in lower seam of contiguous coal seams and the general condition of roadway is good, which has provided great reference value for ground control of roadway in similar conditions.

Key words: contiguous seams, roadway in lower seam, hydraulic expansion bolt, three-dimensional combined control of roof, deformation control