The Houston-based Par Pacific Holdings, Inc., will buy the company that owns the oil refinery in Newcastle for $271.4 million, according to a news release Tuesday.

Par Pacific's (NYSE MKT: PARR) purchase of Hermes Consolidated, LLC, doing business as Wyoming Refining Co., is expected to be completed by late July.

"We don't foresee any changes as far as employment at the refinery," spokeswoman Christine Thorp said.

"We're excited to bring everybody on and get to know the facility better," she said. "As far as new operations, the refinery's been running great."

It employs about 150 in refining and logistics in the area, Thorp said.

The company, however, does plan to add a water treatment plant by 2019, she said.

Wyoming Refinery Co., a subsidiary of Black Elk Refining, LLC, bought the Newcastle refinery in 2011. Since then, it invested $85 million in improvements, and boosted production from 14,000 to 18,000 barrels a day.

The Newcastle refinery includes 140 miles of crude gathering pipeline system, 40 miles of refined product pipelines, and tanks capable of holding 650,000 barrels of product.

One of Wyoming Refining's primary downstream markets is the Rapid City, S.D., metropolitan area with its nearby national parks and monuments.

Its pipeline system serves the Rapid City markets through the Magellan Products pipeline, a proprietary jet fuel terminal in Rapid City and a jet fuel pipeline that connects a proprietary aviation fuel terminal to Ellsworth Air Force Base.

"This acquisition fits perfectly with our previously disclosed acquisition strategy by utilizing our tax attributes and capital sources to build on our refining and logistics capabilities," Par Pacific's President and CEO William Pate said in the news release.

Par Pacific plans to assume $58 million of existing indebtedness at Wyoming Refining and incur $65 million of additional indebtedness of its parent company.

Par Pacific also has operations in Colorado and another refinery in Oahu, Hawaii.