BILLINGS, Mont. (AP) - A North Dakota man has died after falling 8 to 12 feet from an oil rig in northeastern Montana.

Richland County Coroner Marvin Johnson said Clinton Mosby, 20, of Williston, N.D., died at 5:45 p.m. Friday after falling from a rig about 40 miles west of Sidney.

A preliminary investigation showed the steps leading from a tank battery up to a rig floor gave way, causing Mosby to fall. Other workers gave Mosby CPR until he was taken by ambulance to the Sidney hospital.

An autopsy was performed Saturday, but the cause of death probably won't be confirmed for a few days, Johnson said.