The Rulison Site is located 8,154 feet above sea level on the Battlement Mesa in western Colorado, about 12 miles southwest of the town of Rifle and 8 miles southeast of the town of Parachute. On September 10, 1969, the AEC detonated a 40-kiloton nuclear device 8,426 feet below the ground surface. This was the second natural gas reservoir stimulation experiment in the Plowshare Program, which was designed to develop peaceful uses for nuclear energy. The project had been proposed by Houston, Texas based Austral Oil Company and a nuclear engineering firm CER Geonuclear Corporation of Las Vegas, Nevada. These two firms, along with the AEC carried out the experiment Project Rulison.

The objective of the Project Rulison detonation was to stimulate flow of natural gas through fractures created by the blast and use the chimney as a collection chamber. The detonation created a roughly spherical cavity around 152 feet in diameter that contained melted
and vaporized rock. As the cavity cooled, the melted and vaporized rock collected in a puddle at the bottom. Most of the radionuclides were trapped in this puddle as it cooled and formed into a glassy solid. Shortly after the detonation, gravity caused the roof of the cavity to collapse into the cavity chamber. This upward collapsing of fractured rock into the cavity chamber formed a chimney of broken rock to an estimated height of about 274 feet above the point of detonation.

Following the detonation, a reentry well was drilled into the top of the chimney to collect data on gas production by burning the natural gas. Four gas-flaring events were conducted between October 1970 and April 1971. These tests showed that production of natural gas stimulated by the detonation was less than anticipated. Although approximately 455 million cubic feet of natural gas was produced, elevated levels of radioactivity in the gas made it unacceptable for use at that time.

The blast created a wide variety of radionuclides. After the detonation a glass melt puddle formed at the base of the cavity and most of the radionuclides were incased there. This reduced their mobility. There were some radionuclides that were in the water vapor that was removed during the production testing of the natural gas. One of the contaminants remaining in the deep subsurface is Tritium, which is a mobile radioisotope of hydrogen. Tritium has a half-life of 12.3 years and decays to nonradioactive helium.

The DOE is responsible for radioactive and other hazardous materials generated at the Rulison Site. The federal government retains control of the subsurface rights beginning at a depth of 6,000 feet within a 40-acre area surrounding the surface ground zero. DOE monitors gas and water vapor from nearby gas production wells for tritium and other contaminants as a precaution. To date, no test-related radionuclides have been detected.

After some equipment was decontaminated and removed in July of 1972, the site was left alone until 1976. At this time the remaining equipment and facilities were dismantled, inspected for radiation, decontamination, and were removed offsite. Drilling fluid in the effluent pond was removed and sediment and soil samples were collected. These samples showed the pond was contaminated with drilling additives. The pond was drained and enough sediment removed until the pond was within state regulatory limits. Before the pond was filled, eight wells were installed to monitor the groundwater quality. After eight quarters of testing with no migration detected, the wells were decommissioned.

Since 1972, the U.S. Environmental Protection Agency has monitored groundwater annually at and near the Rulison Site. No radioactive contamination associated with the Rulison test has been detected in any samples taken from the nearby municipal drinking water supply springs, the water supply wells on five local ranches, or the spring and three wells on the test site. In 1998 the DOE recommended that the Rulison site be closed and no more action was needed. Although there was radioactive contamination in and around the test cavity in the deep subsurface, the DOE had no plan to remove it because no feasible technology existed.

The federal government prohibits drilling and extracting below 6,000 feet within a 40-acre zone surrounding surface ground zero. These subsurface use restrictions within the Rulison Site boundary will remain in place in permanently. There is a monument at surface ground zero that bears a plaque with an inscription denoting the historical significance of the site and states that excavation, drilling, and removal of subsurface materials below a depth of 6,000 feet is prohibited without permission of the U.S. Government. The Colorado Oil and Gas Conservation Commission established two wider boundaries around the site. If a company wants to drill within a three mile radius of surface ground zero, the COGCC notifies the DOE. The DOE reviews those applications. If a company wants to drill within a half mile of surface ground zero, they must have a hearing before the commission.

Beginning in 2004, energy companies began lobbying for drilling rights within the three mile perimeter. Local politicians argued against allowing wells in the area since too little is known about the potential radioactive contamination from the blast. Based on their computer model studies, the DOE believes that energy companies should be allowed to drill closer to the site. They feel it will be safe even though the drillers would be using a method called hydraulic fracturing near the cavity created by the blast. The process involves forcing liquid under high pressure into the rock to create tiny fractures in the rock. This allows gas to be pumped to the surface. The rock in the cavity is presumably radioactive.

In Janurary of 2009, Presco Inc. was fined a total of $138,000 for violations at wells near the Rulison Site. The fines stem from an inspection in May 2007 carried out by The Colorado Oil and Gas Conservation Commission. Presco had failed to divert snowmelt runoff away from seven drilling locations which caused overflow of wastewater pits. There were puddles of natural gas condensate and unidentified chemical residue at several drilling locations. There were also sacks of chemicals and drums floating in some pits. One of the overflowing pits allowed contaminates to flow into a tributary of Battlement Creek.

In December of 2009, the Bureau of Land Management allowed Noble Energy to proceed with a plan to drill 79 natural-gas wells within three miles of the Rulison Site, the closest of which would be a half mile away from the site. The drilling of the new wells would take place over a three to five year period. The DOE has authority to sample any of the wells for radioactivity. Noble Energy will be required to test for radioactive materials in drilling cuttings and fluids. If the test are negative, Noble can bury them on site.

Radio story on renewed interest in drilling near Rulison Site

References

http://www.lm.doe.gov/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=1065 http://coloradoenergynews.com/2009/12/blm-gives-ok-for-drilling-near-rulison-blast-site/ http://coloradoenergynews.com/2009/07/re-considering-rulison-once-again/ http://coloradoenergynews.com/2009/01/cogcc-approves-fines-for-west-slope-overflow-incidents/!Rioblanco_rulison.gif!