The capacity will be increased from 58,000 barrels per day (bpd) to 68,000 bpd by the second quarter of 2012, subject to permitting requirements.
The average throughput at the refinery was approximately 52,000 bpd, over the past three years.
The company intends to supply the plant with additional crude oil from the crude oil production in the nearby Bakken Shale/Williston Basin area through the Tesoro High Plains Pipeline system.
Tesoro President and CEO Greg Goff said the expansion is in line with the company’s agenda to grow its refining and marketing business in the Northern Great Plains.
"This allows for further integration opportunities in our operations and capitalizes on the steadily increasing domestic crude supply from the Bakken area." said Goff.
Tesoro through its subsidiaries, operates seven refineries in the western United States with a combined capacity of approximately 665,000 barrels per day.
