Bridger signed a five-year deal with Monroe Energy, a wholly-owned subsidiary of Delta Airlines, to supply it with crude, Delta said Monday.

Bridger will supply the company’s Trainer, Pennsylvania refinery with 56,000 bpd per day, about one-third of the refinery’s daily capacity.

Delta said Bridger will provide lower-cost domestic crude from Bakken to replace more expensive foreign crude.

Delta bought the Trainer refinery from ConocoPhillips in 2012 to help manage fuel costs and supplies for its fleet.