While performing a pressure test on a length of plastic pipe, a pipe blanking cap struck a worker after the crimped connection between the ferrule and pipe failed. The injured worker suffered severe leg and hand injuries and was taken to hospital by ambulance. The incident occurred on the night of 26 November 2015 at about midnight and the conveyor adjacent to the test area was in operation at the time.
The incident occurred while testing the integrity of nitrogen delivery pipes after a load haul dump vehicle dragged them from underground to the surface of the mine. Each pipe assembly was approximately 50-60 meters (~200′) long and 150 mm (6″) in diameter. The pipe assembly consisted of 5 meter (15′) lengths of plastic tubing connected via crimped metal joiners. Ferrules were crimped to the ends, allowing pipe assemblies to be connected by Ø150 mm pipe clamps.
The test procedure was to cap both ends of the pipe assembly and pressurize the assembly with compressed air to approximately 800kPa (116 psi). Ball valves were used to prevent the air from escaping while a pressure gauge was fitted to the other end. Leaks were detected by a pressure loss over a 15-minute period.