| 摘要 |
<p>A tabular mineral deposit is mined by drilling overlapping holes in the plane of the deposit, the first hole being drilled in any convenient manner and each subsequent hole being drilled by a box hole type machine with a coring bit. The core breaks up and passes out of the core barrel into the orbit of vanes that transfer the broken rock into the hole being lapped. The broken rock is then removed along the hole being overlapped as by means of a drag line scraper.</p> |
