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,_ <br />' ~ (Page 2) <br />NINE ID { OR PROSPECTING ID f N-80-244 <br />INSPECTION DATE 10-18-94 INSPECTOR'S INITIALS <br />OBSERVATIONS <br />A monitoring inspection was conducted of the Phase 1 leach pad installation. No new <br />deployment of geomembrane or placement or compaction of soil liner was occurring on this day <br />due to wet conditions from recent snows. The weather on this day was clear and warm. <br />Several rolls of geotextile had been deployed in the lower area of the leach pad, on to the <br />textured surface of the geomembrane portion of the composite liner system in the pregnant <br />solution storage area. This ie the first ouch deployment of geotextile which was included <br />in the design for puncture resistance cushioning between the textured geomembrane and the <br />leak collection fill. <br />Several acres of liner had been covered with drain cover fill just below the upper anchor <br />trench on the south aide of the pad. The 16" perforated solution collection/transport pipes <br />had been installed in ewales on the south aide (north facing) part of the pad. Grade (fill <br />thickness) markers for the drain cover fill are 2" PVC pipe lengths painted orange on the <br />bottom 3 feet as approved in the specifications. Resident QA/QC engineer, Terry Mandziak, <br />stated that these grade markers are pulled after thickness verification, also in accordance <br />with the specifications. The painted length of several of the pipes was measured and found <br />to meet the required 3 foot minimum. <br />The lower anchor trench and toe berm crest anchor trench were inspected and measured to be <br />3' deep x 2' wide. <br />The contractor has begun the upstream extension of the Arequa Gulch underdrain into the area <br />recently given archeological clearance. Arequa Gulch flows on this date were only a few gpm. <br />This flow was being held in a small sump and pumped into the 24" solid pipe. The 24" solid <br />pipe will be flushed and capped once the Arequa Gulch flow is routed permanently into the 4" <br />pipe. The protective cap on the 4" pipe was off at the time of the inspection. The <br />protective cap consists of geotextile held on with a pipe clamp. The protective cap was <br />replaced and the pipe clamp tightened before leaving the location. The operator must assure <br />that the protective cape are adequately maintained in order to avoid possible violations. <br />Since the leach pad area was too wet for liner installation, the main earthwork activity for <br />the day shift was reduction of the rock knob in the northeast section of the Phase 1 pad <br />(hill #1) and construction of the main north aide upland diversion ditch. <br />The operator requested a clarification of~ the requirements in the specification for <br />deployment of geomembrane over compacted soil liner that had frozen. it ie the Division's <br />view that Boil Liner cannot be placed on frozen subgrade and cannot be placed or compacted <br />if it ie frozen. It ie also the Division's view, that if soil liner is placed and compacted <br />to meet specification, and ie subsequently frozen prior to geomembrane deployment, that the <br />soil liner must then be retested to determine that it continues to meet the density <br />specification. If the retested soil liner meets the density specification upon retesting, <br />then geomembrane may be deployed, even if the soil liner ie still frozen. If the retesting <br />for density fails, then the contractor must either wait until the soil liner thaws, and <br />moisture condition the soil and re-compact as necessary, or may remove the frozen soil and <br />replace it with soil liner fill that is not frozen. <br />The weekly summary prepared by Golder for the week of~9/26/94 was reviewed and found to be <br />in order. 39 density teats of the soil liner were conducted during this week with no <br />failures. All moisture contents were within 3 percent of optimum with the majority showing <br />compaction at slightly wet of optimum. The weekly summary for the week of 10/3/94 was also <br />reviewed and found to be in order. QC testing of the leak collection fill shows that the <br />stockpiled fill is regularly outside of the approved gradation specification. The contractor <br />has been notified of the non-specification samples. <br />The location of the temporary topsoil stockpile below the primary crusher pad was inspected. <br />The operator has moved moat of the topsoil stored here to a more secure location, but a <br />portion of the topsoil pile will have to remain in the temporary location until some <br />equipment (mostly conveyor parts) is moved off an access road below the topsoil pile. In the <br />