ENERGY COMPANIES DRILL FOR OIL IN THE NIOBRARA FORMATION IN NORTHEASTERN COLORADO

Image #: 18090862 An aging tractor shares land with a oil drilling rig at a farm above the Niobrara oil shale formation in Weld County, North eastern Colorado on May 30, 2012. Gas and oil companies are using large amounts of water to obtain shale oil and gas in a process called hydraulic fracturing or fracking. UPI/Gary C. Caskey /LANDOV