Hey John,
The Natural Bridge I'm talking about is a county park along the Oregon Trail, just off I-25 in central Wyoming. The "plant", (same word but way different meaning from what you had in mind) is a natural gas processing plant which operates on one of the major pipeline corridors near there. Basically, natural gas is gathered from smaller fields in small diameter pipelines, then moves to a larger delivery system which takes it to a major marketing "hub". A typical system needs pressure "boosters", compressor stations, and gas plants.
Unfortunately, with the current energy boom in Wyoming, our natural gas volumes are too large for some of the current transportation systems, so there is a lot of work at these types of locations.