Cimarex Energy Co. is seeking to build a methane and helium recovery plant in southwest Wyoming that would be among the world's largest carbon sequestration facilities. Photo courtesy of Cimarex Energy.

Federal regulators are nearing approval of a natural gas development project in southwest Wyoming that would serve as a testing ground for new mineral extraction technology while becoming one of the largest carbon sequestration projects in the world.

Denver-based Cimarex Energy Co. has asked the Bureau of Land Management for permission to drill three new natural gas wells and a large acid gas injection well where more than 3 million tons of carbon dioxide (CO2) and hydrogen sulfide (H2S) a year would be injected thousands of feet underground.

The $350 million Rands Butte project would involve nearly 38,000 acres of BLM and Forest Service land west of Big Piney, Wyo.

Cimarex said the operation could produce 100 million cubic feet a year of helium -- an increasingly rare gas that is critical in the aerospace and research industries. In addition, the project would extract as much as 39 million cubic feet a day of natural gas from the rich Madison Formation, according to federal records. Go to story #1