| 摘要 |
A mine roof support (10) for use with high coal faces (14) has an elevated platform (13) supported above the base (11). Coal cutting machines (15,20) and conveyors (16,21) are mounted on both the base and the elevated platform, so that upper and lower levels of the coal face can be cut simultaneously. The upper coal cutting machine (20) and conveyor (21) may be mounted on a platform (19) which is slidable forwardly and rearwardly of the support (10) by an extendible jack. The support may be on tracks actuated by jacks. |
