| 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 |
|---|
| "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. |