Laserfiche WebLink
August 2002 -12- 003 -2203 <br />the crown pillars blasted into the mined void. For the one lateral in Phase 1Va (UG -4567, the <br />lateral crown pillar was collapsed, ground surface graded and geogrid was then placed over the <br />area of the lateral as per the drawings. <br />All blast holes that did not intercept the underground working were completely grouted with <br />bentonite slurry prior to blasting the crown pillar and remediating the working. <br />The Squaw Mountain Tunnel is located near the Phase I VLF boundary and extends below the <br />Phase I VLF. Given the close proximity of the Squaw Mountain Tunnel to the VLF liner <br />system, blasting of this feature was not recommended. The tunnel was rernediated in the <br />following sequence: <br />► Confirmation drilling was conducted to locate the depth, limits, and <br />dimensions of the working. <br />► Three rows of holes on five foot spacing were drilled along the length of <br />the working on the Eastern boundary of the working. Each row consisted <br />of two to three "Plug" holes and were cased with 4 -inch ID PVC pipe. <br />► Three- eighths -inch poorly- graded river gravel was poured into each of the <br />Plug holes until refusal. <br />► Between the existing limits of the Phase I VLF and the western plug holes, <br />Flowfill holes were drilled. <br />► The Flowfill was poured into the filling holes until refusal and the volume <br />of Flowfill was recorded. <br />Underground working remediation activities for the Phase IVa Area were performed from <br />August 2001 through May 2002. <br />• <br />1100122031NWTenR posor==03 0400.04740M doc Golder Associates <br />