Cleaning Out Toronto’s Bay Tunnel
The clearing of the long tunnel that conveys the water supply from Lake Ontario to the city of Toronto of its germ-infected sand and at the same time sinking a shaft for a new 72-inch pipe which will join the tunnel shaft has been no slight task during a recent two weeks. The water had first to be pumped out of the tunnel, then 6,000 feet of double electric light wire had to be strung along it to enable the workmen to see during the operation. A light was fixed every 30 feet all the way across the tunnel and the shafts at both ends were lit up, the power and light being furnished from the John street station transformer. The sand was dug up in the tunnel and wheeled to the shafts at both ends of the tunnel. It was there loaded from the carts into large buckets, the capacity of each of which was about one cubic yard. These were raised to the top of the shafts by powerful derricks and swung on to a platform at the edge of the tunnel house, where they were tipped over on to board chutes leading down to wagons and carted away. The 72-inch pipe referred to above will be connected with the big new pump that is to be installed to aid the present pumping machinery. The new shaft for this pipe is 29 feet down, and to keep out the heavy pressure of water which seeps in on all sides, and especially from the south, it has been boarded up all round the inside with heavy planking and timbers. The water, however, leaks in so fast that a steam pump has to be kept going continually so as to keep the water low enough for the men to work. Five feet of hard rock had to be blasted out, then came alternate layers of 10 to 12 inches of shale and of 6-inch hard rock, all of which is raised to the surface by men with shovels. These stood on stages of levels on one side alternately higher than on the other, and the excavated material was tossed up in progression from one stage to another till it reached the top of the shaft. The shaft turns to the east after the wall of the tunnel house till it joins the tunnel shaft, and the last stage in the work—tunneling through the solid rock up to the meeting of the two shafts—was the hardest and most uncomfortable of all, as the hay water could not be kept out in spite of all the steam pump could effect.