The oil refinery in Great Falls is suspending production for about a month while workers make needed repairs.
Calumet Montana Refining LLC officials tell the Great Falls Tribune the $10 million maintenance and repair project has been planned for four years.
Calumet director of government affairs, Dexter Busby, says that while production is stopped, refinery staff work six days a week and another 150 people will be brought in to help.
Busby says the maintenance work involves doing a complete inspection of all the equipment at the refinery and making any necessary repairs along with replacing "tons and tons of piping."
The maintenance project is separate from a planned $275 million expansion that will allow the refinery to process 20,000 barrels of crude oil per day, double its current output.