KBJR 6 has learned more about an early morning fire at Midwest Energy in Superior over the weekend.
Crews had responded to the blaze in the belt system used to move coal early Saturday morning.
Superior fire officials now say the fire may have started with a motor or a bearing breaking.
They say it was not a dust fire, and the dust collection system was working at the time.
Officials say the fire started at the top of the facility and traveled down the rubber belt to the basement.
No employees were hurt.
Damages are still estimated between $500,000 and one million dollars.