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New Zealand Listener, Volume 35, Issue 896, 5 October 1956, Page 23

finished by pumping cement grout behind the lining: No special equipment was worn by this team of 25 men; but precautions were taken against the sbends 2 vocational disease associated with deep-sea diving and tunnelling under compressed aif conditions. Shell s resident senior medical officer saw that cases of cbends were almost non-existent as 4 result of regular check-ups on all personnel going underground. Shell iS the largest refinery operator Mud-Hogs 9 9 in the United Kingdom: Its four refineries together produce more than Io million tons of essential under the Thames products a year from crude petrol- Soft-ground tunnel miners, popularly Working eight-hour shifts under eum brought in from overseas: known as "mud-hogs' worked 50 compressed air and operating behind These refineries are sited in different feet below the Thames to build a a tunnel sshield" the "mud-hogs parts of the country to ensure the 9oo-foot long tunnel to carry cool- moved forward at the rate of Ioo the most efficient distribution of ing water for use in operations of feet a month: Compressors driven their products: Shell Haven Refinery, near Southend by electric motors, with diesel No. 8 of a second series 0f articles published by on-Sea, Essex. Along this 9 foot engines as a standby, maintained the THE SHELL COMPANY OF NEW ZEA: LAND LIMITED (Incorporated in England) diameter tunnel, river water from aif pressure and kept the water from the Thames is carried to 4 large entering the tunnel while they were pumphouse built 30 feet below working: As the miners excavated ground level: the mud from the river-bed and brought it to the surface, they erected 2 cast iron lining, which was bolted together to form a tunnel in the same way as was done in the construction of London" S under- ground railways the outside was Above : Miners at the tunnel shelf face: Left : Removing spoil from the tunnel face by light railway. Right : Looking upwards Gn the 18 ft. diameter shaft at landward end of tunnel.