"This is a continuation of our efforts to make sure that this is a safe, clean, reliable refinery that is able to meet demand," Jake Reint, Flint Hills' director of public affairs told the Minneapolis Star Tribune.
The Tribune reported Friday the refinery is already the nation's 14th largest with a current processing limit of 320,000 barrels of oil per day.
For the past five years, the plant has been operating between 82 percent and 90 percent of its capacity, the Star Tribune reported.
The upgrades are expected to create 500 construction jobs on top of the 400 to 2,000 contracted employees who work at the refinery on and off and the 950 permanent workers at the plant.
With the extra jobs, there "will be a lot of folks getting fed for the next two or three years out there," said Harry Melander, president of the Minnesota Building and Construction Trades Council.
Flint Hills director of public affairs Jake Reint said the aim was to create a "safe, clean reliable refinery that is able to meet demand."
He also said the upgrade was not determined by the increased production of oil in Canada and North Dakota -- although that doesn't hurt, either.
"There is no doubt that having access to a stable crude oil supply is vital. We are geographically blessed as a state to have access to that," he said.