BATTLEMENT MESA, Colo. (AP) — A rig that has begun drilling some of the first of many natural gas wells Ursa Resources plans to develop in this western Garfield County residential community stands out in the sense that it doesn't stand out.

Some 50 feet shorter than a typical drilling rig, it nearly hides behind a 32-foot-tall sound wall that Ursa has erected around the pad where it has begun drilling wells at its first Battlement Mesa pad.

"It's very small. We sometimes call it the riglet," Hans Wychgram, drilling manager for Ursa, said during a tour the company recently provided to participa...