Coaxing Oil from Huge U.S. Shale Deposits

San Francisco Chronicle – Underneath the high, scrub-covered rangeland of northwest Colorado is the world’s biggest oil field. Getting the oil out of the ground, however, is one of the world’s biggest headaches.

The area’s deposits of oil shale are believed to be larger than all the oil reserves of the Middle East. But past attempts to get at this oil locked in tarry rock have cost billions of dollars and raised the prospect of strip-mining large areas of the Rocky Mountain West.
SFGate.com