Laserfiche WebLink
999 <br /> JOHN F. ABEL,JR. <br /> MINING ENGINEER @0651 e yC bbC 310 LOOKOUT VIEW COURT <br /> DENVER GOLDEN.CO 80401 <br /> O 304901 <br /> OFFICE <br /> FAXX 27878-8163 <br /> August 19, 1996 <br /> Mr. Larry Perino <br /> Sunnyside Gold Corp. <br /> P.O. Box 177 <br /> Silverton, CO 81433 <br /> Dear Larry: <br /> As you requested I have calculated the designs for two <br /> bulkheads for the Gold Prince Mine bulkheads. One structural <br /> bulkhead to be constructed in the solid rock closest to the portal <br /> and another bulkhead to prevent the water entering the tunnel <br /> through the blocky and seamy rock between the two bulkheads from <br /> freely exiting the portal. The second near portal bulkhead will <br /> force the water entering the tunnel back into the fractures in the <br /> near surface latite porphyry. <br /> The recommended 5-foot thick interior structural bulkhead <br /> located in solid rock 150 feet inside the portal was primarily <br /> designed to reverse the flow of water out of the Gold Prince Mine <br /> portal. The predicted head for this bulkhead is 20 feet, the <br /> height necessary to force impounded water back into the Sunnyside <br /> Mine. This bulkhead has the capability of withstanding the maximum <br /> 65-foot head that could develop if the flow path back into the <br /> Sunnyside Mine should become blocked by any future fall of ground. <br /> The bulkhead calculations are attached at the end of this letter <br /> report. <br /> The second bulkhead, designed to resist 14 feet of head, has <br /> been located in blocky ground 14 feet inside the portal. The <br /> purposes of this 2.5-foot thick bulkhead are to impound the near <br /> surface groundwater that drips the Gold Prince Mine portal between <br /> the two bulkheads during the melt season and to force that water <br /> back into the fractured near-surface rock and to reestablish the <br /> natural flow of groundwater in the weathered near-surface rock. <br /> The blocky rock upstream from this bulkhead is obviously too <br /> permeable to permanently retain the temporarily impounded surficial <br /> groundwater. The calculations for this bulkhead design follow <br /> those for the main bulkhead. <br /> The design calculations demonstrate that plain concrete <br /> bulkheads will function for the structural bulkhead requirements <br /> and that no tensile reinforcement is necessary. However, a <br /> temperature and shrinkage rebar cage is necessary at both faces of <br /> both bulkheads. The temperature and shrinkage rebar was designed <br /> in accordance with the American Concrete Institute (ACI) <br />