| Barrick Goldstrike Mines | Luminant | |
| BHP Minerals - Area III | Newmont Gold | |
| BHP Minerals - Navajo Mine | Powder River Coal (North Antelope Coal Rochelle) | |
| BHP San Jan Coal Company | Powder River Coal - Rawhide Mine | |
| Bridger Coal Company | Sabine Mining Company | |
| Catenary Coal Company | Seneca Coal Company | |
| Cardinal River Coal | Spring Creek Coal Company | |
| Colowoyo Coal | Suncor Energy | |
Cordero Mining Company | Syncrude Canada Ltd. | |
Denver Magnetic, Power & Distribution | Thunder Basin Coal Company | |
| Drummond Coal Company | Texas Westmoreland Coal Company | |
| Estevan Coal Corporation | TransAlta Utilities | |
| Kennecott Utah Copper | Trapper Mining Company | |
| Kiewit Mining Group | Twenty Mile Coal | |
| Kiewit Pacific Company | Walnut Creek Mining Company | |
| Kerr McGee Coal Corporation | Usibelli Coal Mine, Inc. (Alaska) | |
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