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.