| 摘要 |
<p>A support for the roof in longwall mining operations includes a gob canopy at the rear of a roof canopy. The gob canopy can move about a vertîcal pivot and a horizontal pivot by operation of a hydraulic actuator. To stabilize the support, the gob canopy moves into or out of contact with the roof at the rear of the roof canopy. The actuators can move the gob canopy to the left or right side of the roof canopy about a vertical pivot so that a skeg member on the upper surface of the gob canopy drags along the mine roof for steering the roof support when it is advanced toward the mine face. Gaps between the gob canopies of side-by-side roof supports function in the manner of grizzly bars to permit recovery of small pieces of gob roof rock.</p> |
