U.S. Energy Minerals: Unconventional Resources for the Future

William A. Ambrose, Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX

With increasingly rising oil prices, energy minerals have become more economically attractive and offer a valuable, alternative energy source for the future. The Energy Minerals Division (EMD) of the American Association of Petroleum Geologists (AAPG) is organized to advance the science of geology related to energy minerals, which include coal, coalbed methane, uranium, gas hydrates, gas shales, oil shale, tar sands, and geothermal energy. The U.S. energy mineral resource is enormous. It includes over a trillion tons of identified coal of which 275 billion tons is technically recoverable, >200 billion tons of oil shale, >250 million pounds of U₃O₈ producible at $30/lb., approximately 690 Tcf (trillion cubic ft) of coalbed methane, between 467 and 607 Tcf of shale gas, over 3 billion barrels equivalent of tar sands, and 2.4 x 10¹⁹ joules of identified and undiscovered convection hydrothermal resources (energy equivalent of 430 billion barrels of oil). The potential U.S. gas hydrate resource may be many thousands of Tcf. Energy mineral resources are associated with varying degrees of technical and economic challenges. For example, increased coal production impacts mining safety and the existing transportation infrastructure. Oil shale production and refining requires energy and large volumes of water. Both coalbed methane and uranium commonly require disposal of water and radioactive material, respectively. Production of gas hydrates is not yet technically feasible. However, gas hydrates could become a sustainable source of natural gas within the next 5 to 10 years, thereby adding significant volumes of gas to the U.S. resource base.