SURFACE COAL MINING-1975

During 1935 the U.S. Geological Survey published new coal reserve figures for the United States. The Survey increased its estimate of United States' coal reserves by 23 percent to 4 trillion tons, or about one-half of the world total. The report estimates that, under present technology, about 434 billion tons of coal in this country are recoverable. It also states that one-third of this total is amenable to recovery by surface methods, i.e., can only be mined by surface methods.