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Larry Perino Page 2 eptember 5, 1994 <br /> about two quarts, that had collected in depressions in the floor <br /> was vacuumed from within the bulkhead form during my inspection. <br /> The Terry Tunnel is the first bulkhead to be constructed with <br /> a bypass pipe and a 1-inch diameter water pressure monitoring pipe. <br /> The March 2, 1994 design for the Schedule 40 (Standard Weight) <br /> 6-inch diameter 316L Stainless Steel bypass pipe was verified <br /> during my inspection. Sunnyside Gold Corp. substituted Schedule 80 <br /> (Extra Strong) 316L Stainless Steel for the required Schedule 40 <br /> (Standard Weight) . The increased strength of the thicker wall <br /> pipe, 0. 432 inches versus the design 0. 280 inches, is unnecessary <br /> but conservative. The flow capacity of the stronger pipe inside <br /> diameter of 5.761 inches installed exceeds the minimum diameter of <br /> 5. 680 inches to pass the maximum flow requirement of 1370 gpm. The <br /> 3/8-inch thick by 2-inch annulus factory fabricated thrust ring <br /> plate was present on the pipe at the specified 5. 5 feet from the <br /> downstream (airside) face of the bulkhead. The thrust ring also <br /> acts as a waterstop for any water moving along the concrete/pipe <br /> surface interface. An additional 3/8-inch thick by 2-inch annulus <br /> factory fabricated combination thrust ring and waterstop was <br /> present at the interior face of the bulkhead form. A third <br /> 0. 035-inch thick, non-load bearing waterstop had been installed on <br /> the pipe 2 .75 feet from the downstream face of the bypass pipe. <br /> The design requirement detailed in the February 25, 1994 bypass <br /> pipe design calculations have been grossly exceeded. Three <br /> combination thrust rings and waterstops are present at the same <br /> locations along the 1-inch diameter 316L Stainless Steel water <br /> pressure monitoring pipe. They are not needed, but represent <br /> conservative precaution. The corners of both the upstream and <br /> downstream pipe penetrations of the rebar cages had been reinforced <br /> by #6 rebar. The corner reinforcement installed where the bypass <br /> pipe passed through the upstream temperature and shrinkage rebar <br /> cage was not required because no bar sections were removed for the <br /> 6. 625-inch OD bypass pipe to pass through the 12-inch spaced #6 <br /> rebar cage. The American Tunnel bulkhead willorequire corner <br /> reinforcement for the upstream temperature and shrinkage rebar cage <br /> because a section of one vertical and one horizontal bar must be <br /> removed where the 12.750-inch OD bypass pipe passes through the <br /> 12-inch spaced #6 rebar cage. <br /> Filling of the form commenced at 4 : 08 pm on September 1, 1994 <br /> and proceeded continuously until completed at 11: 20 pm. I observed <br /> samples taken at 4: 55 pm, 6:25 pm, 7 : 55 pm, 9: 12 pm, 10: 17 pm and <br /> 11: 20 pm. Once started, the filling of the Terry Tunnel Bulkhead <br /> was the smoothest to date. <br /> The water in the Terry Tunnel is currently being pumped <br /> through 6-inch diameter HDPE pipe connected directly to the 6-inch <br /> diameter bypass pipe. A timber cofferdam has been constructed <br /> approximately 20 feet upstream from the Terry Tunnel Bulkhead. The <br /> cofferdam provides for passing of water in the Terry Tunnel through <br /> the bulkhead by means of an HDPE line and Y into the presently <br /> operating HDPE pump line. This timber cofferdam was reinforced by <br /> banking concrete spillage, by concrete left over after each sample <br />