Number | Name | Date | Kind |
---|---|---|---|
2776824 | Osterhus et al. | Jan 1957 | |
3307879 | Bergmann | Mar 1967 | |
3726562 | Wharton | Apr 1973 | |
3873157 | Stoltefuss et al. | Mar 1975 | |
3929378 | Frenyo et al. | Dec 1975 | |
3965995 | Sugden et al. | Jun 1976 | |
4045088 | Bechem | Aug 1977 | |
4111488 | Sigott et al. | Sep 1978 | |
4230372 | Marten | Nov 1980 | |
4312541 | Spurgeon | Jan 1982 | |
4548442 | Sugden et al. | Oct 1985 | |
4838615 | Oldham | Jun 1989 | |
5087102 | Kiefer | Feb 1992 |
Number | Date | Country |
---|---|---|
2723675 | Nov 1978 | DEX |
Entry |
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"World Tunnelling", issue of Jun., 1991, p. N52, in part showing a Gantry (Portal) Miner, in an advertisement of Advanced Excavation & Cutting Technologies, a Division of Alpine Equipment Corporation, P.O. Box 767, State College, Pa. 16804. |