REV15438 - Laserfiche WebLink

Home Browse Search

_ • ~,- ril 2001. GEI Consultant;, Inc., Geotechnical Data Reoorf Bruce Park i ;. u,1. Delta County. ~olorodo, submitted to Bowie Resources, Limited. ._ ~'~,cr~ia. Executive Summary Page 1 of 2 The purposes of this report are to present a) the results of engineering analyses of mine induced seismicity on Bruce Pork Dam and on a landslide on the right (looking downsireamJ side of Bruce Park Reservoir and b) our opinions regarding possible impacts to Bruce Pork Dom and the Landslide from mine-induced seismicity. For the purpose of the analysis. we considered that the proposed mining activity near the dam and reservoir would take place over a period of 2 years. Permanent deformations were evaluated for two conditions: a single rrragnitude 4.2 mine-induced seismic event and cumulative effects of a combination of t00 magnitude 1.75 events. 20 magnitude 2.0 events, ar~d 5 magnitude 2.5 events. Based on the results of the evaluations performed and documented in this - • t we conc':ude fhe following: 6~uce Pork Dam and Bruce Park Saddle Dam should not be -- ::,dversely impacted from mine-induced seismicity generated from rmg wall mining ai the Bawie Resources mine for the following ~.asons: ._ a. The dan~,s end foundations consist of clays soils that are not •- suscept~b.e to iiquefar_flon dur~rg seismic loading, :: b. Permanent deformations of the dam and saddle dam during ._ seismic Loading should be insignificant because the expected •- ground motions (accelerations) at tt,e don, and saddle dam '- sites are less than fne computed yield acceleration. ._ ?. The computed static factor of safety for the existing lar~c]stide .- caepends on the pore wafer conditions in the slope and would ~- range from about 1.1 to 2.0 for phreatic surfaces ranging from the ~- ground surface to the top of bedrock, respectively. ._ 3. Q. permanent deformation of about 9 inches may occur in the -- axisting landslide if a rate magnitude 4.2 mine-induced seismic "- event occurs under conditions where the phreatic surface in the ._ i~~ndslide is of the ground surface. If the phreatic surface is at mid- - :~pih or at the bottom of the landslide. o rare magnitude 4.2 event ~- .• ~. ~ ,T generate permanent deformations of 1.5 and 0.3 inches.