Rio Blanco Nuclear Test Site, Colorado

An underground nuclear test took place at this site in 1973, to investigate the possibility of using nuclear explosions to extract natural gas from low-permeability sandstone deposits. The test, called Rio Blanco - the last in the Plowshare Program - was performed by the Atomic Energy Commission in conjunction with two corporate partners, CER Geonuclear and the Continental Oil Company (Conoco), using three simultaneously detonated 33-kiloton bombs, each at the bottom of a shaft more than a mile deep. The blast was marginally successful in causing the gas to collect in the cavity and fissures produced by the bombs, however the gas was too radioactive to be sold commercially. A similar nuclear-device gas stimulation test called Project Rulison, was performed nearby in 1969.