SUPPLY MATERIALS HOIST WAS BEING USED TO DROP 5 LOADED SUPPLY CARS DOWN THE SLOPE INTO THE MINE. CAR WAS APPROXIMATELY HALF WAY DOWN WHEN A HYDRAULIC HOSE RUPTURED, SPRAYING THE BRAKE DRUM PAD S. THIS CAUSED CARS TO QUICKLY CONTINUE DOWN THE SLOPE CAUSING A WRECK WITH PARKED SUPPLY CAR ON BOTTOM.