Number | Name | Date | Kind |
---|---|---|---|
3205942 | Sandberg | Sep 1965 | |
4043596 | Ridley | Aug 1977 | |
4360233 | Ricketts | Nov 1982 | |
4423906 | Studebaker | Jan 1984 |
Entry |
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Sellers et al, Rock Mechanics Research on Oil Shale Mining, Presented at AIME Annual Meeting, 1971. |
Mining Engineer's Handbook, Peele, Ed., 3rd Ed., vol. 1, pp. 477, 478, 1959 John Wiley & Sons, N.Y. |