Laserfiche WebLink
999 <br /> JOHN F.ABEL,JR. (� <br /> MINING ENGINEER <br /> 7� 310 LOOKOUT VIEW COURT <br /> GOLDEN.CO 80401 <br /> 303-27"901 <br /> FAX 27"163 <br /> March 2, 1994 <br /> Mr. Larry Perino 1 <br /> Sunnyside Gold Corp. �p <br /> P.O. Box 177 <br /> Silverton, CO 81433 <br /> Dear Larry: <br /> This is the letter report you requested concerning Aftai <br /> requirements for: 1) a thrust collar on the bypass and post-- <br /> impoun n rainage pipe for the Terry Tunnel Bulkhead, 2) <br /> substitution of a combination of Schedule 40 (Standard Weight) 316L <br /> Stainless Steel and HDPE piping for the construction bypass and <br /> post-impoundment drainage pipe for the Schedule 80 (Extra Strong) <br /> steel pipe design for the American Tunnel Bulkhead and 3) <br /> substitution of a thrust collar for shear studs on the construction <br /> bypass and post-impoundment drainage pipe for the American Tunnel <br /> Bulkhead. <br /> 1) The original Terry Tunnel bulkhead design did not include <br /> a bypass and post-impoundment drainage pipe. The purpose of the <br /> bypass and post-impoundment drainage pipe is to bypass the more <br /> acidic, lower pH, water exiting the Terry Tunnel until after <br /> construction and closure of the American Tunnel Bulkhead. The <br /> Terry Tunnel Bulkhead bypass pipe will permit continued treatment <br /> of the 5.9 to 5. 7 pH water exiting the Terry Tunnel from moving <br /> through old Sunnyside Mine workings and will prevent that water <br /> from mixing with the essentially neutral current 7. 3 pH American <br /> Tunnel drainage and lowering the overall pH. The Terry Tunnel <br /> bypass pipe was sized at 6-inch diameter, Schedule 40 (Standard <br /> Weight) 316L Stainless Steel pipe in the February 25, 1994 memo <br /> "Terry Tunnel, Bypass Pipe Calculations" enclosed with this letter <br /> report. The Terry 'runnel bypass pipe has been specified as 316L <br /> Stainless Steel because of the corrosion potential of the acidic <br /> drainage that will flow through the pipe. <br /> A factory fabricated 316L Stainless Steel thrust collar, 3/8- <br /> inch thick with a nominal ID of 6. 625 inches and an OD of 10. 625 <br /> inches, welded to the bypass pipe on both sides of the collar is <br /> specified to support the maximum possible 8090 lb of thrust that <br /> would develop under the maximum 650 feet of head (280 psi) . Shear <br /> studs are not available in 316L Stainless Steel and are not an <br /> option to resist the axial thrust developed when the valve is <br /> closed and the maximum head of 650 feet is applied. The design <br /> calculations are presented with the other Terry Tunnel Bypass pipe <br /> calculations attached. This is the same type thrust resisting <br />