The Energy Department said it plans to inject up to 35,000 tons of carbon dioxide during a six-month demonstration at the San Juan Basin near Navajo City, N.M.

"Unlike other enhanced coal bed methane recovery projects, this demonstration will develop ways to maximize permanent storage of the injected CO2, a process called geologic carbon sequestration," officials said in a statement. "Many coal beds in the United States are saturated with natural gas (methane) but the gas is difficult to produce because methane chemically binds to coal. However, CO2 shares the same tendency to bind to coal.

"Injecting CO2 into the coal bed essentially displaces the methane and makes the gas easier to produce," the officials said. "This process is called enhanced coal bed methane recovery."

The Energy Department's Southwest Regional Partnership, which is managing the project, is led by the New Mexico Institute of Mining and Technology, and includes the states of Colorado, Oklahoma, New Mexico and Utah, as well as portions of Arizona, Kansas, Texas, and Wyoming.