Results: 1 - 4 of 4
Apr 30, 1974
Open File Report
… beneath a substantial cover of overburden, where the iron bed was … 50-foot thickness of clay till overburden to expose the iron bed, …
Dec 31, 1984
Open File Report
… pits 02, 03 and 04. The bedrock overburden in many places in the …
Dec 31, 1974
Economic Geology Report
… high grit content, or thick overburden reduce the desirability …
Dec 31, 1979
Economic Geology Report
… Exploitation is uncertain as overburden is thick in many …