Laserfiche WebLink
<br />' SECTIONONE Purpose and Scope of Study <br />Interceptor Canal <br />' The tailing impoundment is surrounded by an tuilined dean water interceptor channel. The <br />channel collects and diverts surface water runoff azoand the perimeter of the impournhnent, <br />dischazging it downstream of the facilities. <br />1.2 PURPOSE AND SCOPE OF SERVICES <br />' Based on the studies performed by W.W. Wheeler & Associates, we understand that Climax may <br />store the precipitation from extreme storm events (PMP) within the impoundment. Vl'e have <br />' assumed that Climax will release the decant water tluough the spillway at a reduced rate. During <br />the PMP event, the decant pond elevation was assumed to rise to near the dam crest n;ducing the <br />beach width from 1,000 feet for the normal operating pond conditions to 100 feet following the <br />' PMP event. The purpose of this study is to evaluate the impact of the elevated decant. pond and <br />phreatic surface conditions on the overall dam stability. <br />URS Greiner Woodwazd-Clyde (Woodwazd-Clyde) was contracted by W.W. Wheeler & <br />t Associates to conduct the necessary geotechnical analysis and prepaze this report. Ou.r work <br />consisted of three tasks, which include: <br />' Task 1-Dam Seepage Analyses <br />Dam seepage analyses were performed to evaluate the changes in the embankment seepage <br />' conditions and estimate the phreatic surfaces that result from storage of the PMP everllt. <br />Analyses were performed for both the current dam elevation and ultimate design dam elevation <br />of 8900 feet. Seepage analyses were also performed to estimate the post-closure seepage <br />' conditions for the ultimate height geometry following the PMP event. The estimated 1>hreatic <br />surfaces were used later to estimate embankment stability. <br />' Task 2-Dam Stability Analyses <br />Dam stability analyses were performed to evaluate the embankment stability for the current <br />' height, ultimate height, and post closure conditions with the raised phreatic surfaces rl;sulting <br />from the PMP event. Both static and post-seismic loading conditions were evaluated. <br />' Task 3 -Report Preparation <br />Results from the dam seepage and stability analyses were compiled, discussed and prE;sented in <br />' this geotechnical report. This report also contains our conclusions and recommendations based <br />on the results of the above mentioned analyses. <br /> <br /> <br />J <br />~^~` N:\PROJECT516B4061B HENOERSON MILL BPxG\SUB OOY.O_PROJ DELNVI#11LL R3.D0(.12WUL-01\\ 1-2 <br />v-va <br />