HOISTMAN WAS RUNNING HOIST BEFORE SHIFT STARTED AND LOST POWER. CALLED ELECTRICIANS, MSHA WAS CALLED AT 7:30 AM TO REPORT HOIST DOWN. ELECTRICIANS FOUND FAULTY BRAKE WEAR LIMIT SWITCH AND REPL ACED IT. HOIST WAS RETURNED TO SERVICE AND MSHA WAS CALLED AT 8:25 AM ON THE SAME DAY.