EE WAS TAKING TURNS WITH 2 OTHER EMPLOYEES SHOVELING DIRT OUT OF THE END OF A 8' PIPE THAT WAS TO BE USED AS A TUNNEL FOR A CONVEYOR BELT. THE DIRT WAS LEFT IN THE PIPE AFTER IT WAS DRAGGED TO THE LOCATION. ON ABOUT THE 2ND OR 3RD SHOVEL FULL, HE COPMPLAINED OF BACK PAIN.