Results: 1 - 2 of 2
Sep 30, 1963
Information Series
… Board's estimate of the reserves that they contain. The … 300 and 2600 feet of overburden. Reserves have been estimated for … basis of the magnitude of the reserves and the adequacy of the …
Mar 20, 2007
Information Series
… consumption rates these reserves will be exhausted in fifteen years. As reserves are depleted the cost of …