Texas is now the sixth leading coal-producing state in the Union. Maximum development of this resource, which depends greatly on the development of large-scale mining operations and transportation networks, as well as on markets, has not yet been attained. M. K. Hubbert, The energy resources of the earth, Scientific American, Vol. R. C. Milici and E. V M. Campbell, Virginia coal resources-a long term view, Virginia Coal and Energy Jour. Coal production and projected coal production for the Appalachian basin.
Region is in mature phase of resource life cycle.
Production and projected production of coal in the Illinois basin. Projected decline is based on a cumulative production of about 10 billion tons, remaining reserves of 21 billion tons and an annual reserve depletion rate of about 0.6 to 1.1 percent over the next century. Reserves are probably overstated because of the high sulfur content of coal, and actual decline rates may be greater than shown. Region is in mature phase of resource life cycle. Coal production from the northern Rocky Mountains region.