At approx., 1:45am, the loader operator was notified by rock truck driver that the loader was on fire at the rear of the cab. Both EE's used their fire extinguishers to put out the fire. However, the fire started burning again. This time a call was made to 911 & MSHA was notified @2:16am when it was realized fire had burned for 30 mins. without being extinguished.