| 摘要 |
754,858. Earth-tunnelling methods and apparatus. EBELING, W. April 9, 1954 [Aug. 14, 1953], No. 10464/54. Classes 68(1) and 85 The forming of large bores, e.g. tunnels or headings, or the mining of mineral by completely boring out the seam is done by first boring a large hole II in any suitable manner and thereafter forming further large holes III, IV and so on, in such a manner that during the boring of each of said further holes one or more previously bored holes serves as a guide for the boring machine. A boring machine 20 such as that described in the referred to Specification 743,931 is used. The machine may be used alone or in conjunction with supporting structures 25, 26, 27, 28 and 29. |
