Project Rio Blanco

Project Rio Blanco was an underground nuclear test that took place on May 17, 1973 in <a href="/facts/Rio_Blanco_County,_Colorado/wNLAYWLd">Rio Blanco County, Colorado</a>, approximately 36 miles (58 km) northwest of <a href="/facts/Rifle,_Colorado/CadXcM0J">Rifle</a>.
Three 33-kiloton nuclear devices were detonated nearly simultaneously in a single emplacement well at depths of 5,838, 6,230, and 6,689 feet (1,779, 1,899, and 2,039 m) below ground level. The tests were conducted in fine-grain, low-permeability sandstone lenses at the base of the <a href="/facts/Fort_Union_Formation/Gc9H0qBI">Fort Union Formation</a> and the upper portion of the <a href="/facts/Mesaverde_Formation/xWNndnYF">Mesaverde Formation</a>.
This was the third and final natural-gas-reservoir stimulation test in the <a href="/facts/Operation_Plowshare/tkkg1HWW">Plowshare program</a>, which was designed to develop peaceful uses for nuclear explosives. The two previous tests were <a href="/facts/Project_Gasbuggy/qmhgGJmE">Project Gasbuggy</a> in New Mexico and <a href="/facts/Project_Rulison/jbbzvLH9">Project Rulison</a> in Colorado.
The <a href="/facts/United_States_Atomic_Energy_Commission/7VXrvVJ9">United States Atomic Energy Commission</a> conducted the test in partnership with CER Geonuclear Corporation and <a href="/facts/Conoco_Inc./6THRSXYz">Continental Oil Company</a>.
A placard, erected in 1976, now marks the site where the test was conducted. The site is accessible via a dirt road, Rio Blanco County Route 29.

Project Rio Blanco open-in-new

Project Rio Blanco