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• (Page 2) <br />MINE ID # OR PROSPECTING ID # M-94-117 <br />INSPECTION DATE 09/3q~ 98 INSPECTOR'S INITIALS CLK <br />r <br />OBSERVATIONS <br />The following observations were made during the continued installation of the GCL and 60 ml <br />HDPE liners in the expanded pond area at Gold Hill Mill. <br />1) Rocks continued to be removed from the subgrade throughout the day, sand covering areas <br />w}iere rocks could not be dug out, and organic material was removed from the anchor trench. <br />The southern slope had to be re-graded when the slope was found to be ~1.25H:1V in some <br />areas; soil was added and the grade softened to 1.SH:1V all the way along. Problems with <br />the rock layer in the anchor trench led to it being jack-hammered out and then removed. <br />Extra GCL liner was placed on a section of rock on the south slope which (due to angle and <br />depth) could not be removed or adequately covered with sand. <br />2) Colorado Lining Co. continued to lay down the GCL layer (Bentofix) and HDPE liners per the <br />specs. A small amount of standing water was found on the HDPE when the liners arrived. The <br />ground was slightly damp at Sam, but not damp enough to clump, and the areas underneath <br />the HDPE liner (without a GCL layer underneath) left in place the night before were <br />checked and proved to be dry. Water spilled from the HDPE onto the GCL was broomed and <br />scooped off, and an extra layer of GCL was placed over the wet area. <br />3) .Air-pressure testing was conducted on all welds. The seals had to be able to hold 34 <br />p.s.i. for 5 minutes, with a drop in pressure of less than 4 p.s.i. Welds that could not <br />hold that pressure were noted on the liner in white marker, while those which passed the <br />test were also noted with the time of the test and the amount of pressure used. According <br />to the specs, the seals must hold 27 p.s.i. for 5 minutes with a drop in pressure equal <br />to or less than 3 p.s.i. Therefore the tests conducted on the welds were done to <br />manufacturer's specifications. Where a good reading could not be obtained, the weld was <br />cut and re-tested over a smaller area, <br />4) The old liner from the Phase II area was welded to the new, completed liner in order to <br />anchor the new liner at the end of the day. This was said to be a temporary anchoring <br />measure, not something that had to become a permanent part of the pond design. <br />5) Vacuum box tests of some of the welds which did not pass the air-pressure tests were done <br />following the completion of the pond lining. Cap-seals (extrusion, one-layer welds) were <br />done on all rips, tears, and inadequate seams. Where the vacuum box test found holes in <br />the seams or past patching, new welding was done. Repairs on this liner were not <br />completed at this time, and the weld along the old liner was not checked at this time. <br />I & E Contact Address <br />NAME Maxine Stewart <br />OPERATOR ITEC Environmental <br />STREET 707 17`" Street, Suite 310 <br />CITY/STATE/ZIP Denver, Co 80202 <br />cc: Carl B. Mount, DMG <br />^ CE <br />^ BL <br />^ FS <br />^ ~ <br />^ FIMWMD (CH) <br />^ SE <br />^ WQCD (CH) <br />^ Other <br />Ted Gengler, ITEC (see above) <br />Will Hamling, ITEC (see above) <br />Mark Steen <br />P.O. Box 1523 <br />Longmont, CO 80502 <br />