| 摘要 |
<p>The invention relates to a method of, and an apparatus for, determining the progress of mining by detecting the advance path of a mine roof support unit using a path-measuring device 14 which measures the working stroke of an advance ram 4 of the roof support unit. To avoid errors in measurement, the path-measuring device 14 is activated only when a minimum advance force is measured by a force- measuring device 16, 17 interposed between the roof support unit and an associated conveyor 3. <IMAGE></p> |
