HOIST OUTAGE, WHILE SERVICING AND MAKING ROUTINE CHECKS ON THIS HOIST, EE FOUND ONE COMMUTATOR INTERFACE BAR LOOSE IN THE HOIST MOTOR. PERSONNEL IN THE MINE WERE NOTIFIED AND PRODUCTION WAS SH UT DOWN. CREWS WERE TOLD TO EAT LUNCH & STAND BY TO TRAVEL TO SHAFT AREA. THE COMMUTATOR INTERFACE BAR WAS CLEANED & SOLDERED. TEST RUNS MADE & RELEASED FOR SERVICE AT 1:05 P.M.