INSPEC01122 - Laserfiche WebLink

Home Browse Search

(Page 2) NINE ID / OR PROSPECTING ID / N-80-244 INSPECTION DATE 11/28/94 INSPECTOR'S INITIALS CS OBSERVATIONS A monitoring inspection of Phaee 1 leach pad construction was conducted. The "winterization" berm was being constructed at the northeast margin of the currently lined extent of the Phaee 1 pad. The berm ie being constructed using the soil liner fill stockpiled on Hill No. 1 north of the pad footprint. An elevating scraper was delivering fill from the stockpile to the berm location, and a motor grader was shaping the berm. Some large clods of frozen soil were observed in the fill, however this constituted lees than 15 percent of the fill, and the constructed berm should be more than adequate to fulfil its intended function (etormwater and enowmelt retention), particularly since it ie to be covered with VLDPE geoeynthetic. The earthworks contractor (Ames) was placlnq drain cover fill on, and just below, the Phaee 1 tce berm. CAT 773 haul trucks were observed windrowing fill on a peninsula of drain cover just north of the pregnant solution collection Bump. An area that appeared to be lase than 5 feet thick was being traversed by the trucks. When this was pointed out to the operator, the situation was immediately corrected by placement of additional fill to attain the 5 foot thickness. It was observed that laborers were removing oversize rocks from the working faces of drain cover fill placement. This activity was under the observation of Golder CQA personnel. The oversize rocks removed were being placed in piles away from.the working face of the fill to be loaded out of the pad area at a later time. On two occasions this date I had to move piles of removed oversize just as it was being buried by advancing drain cover fill. There ie no question that these piles would have remained on the liner, buried by drain cover, if I had not been present. This Lax approach to the oversize removal effort at a time when a Division inspector was present raises a question of the diligence to oversize removal that ie applied when state inspectors are not on site. Both Golder and cripple Creek 6. Victor Gold representatives were notified of the poor oversize removal performance observed. If similar performance ie observed in the future, either during next springs construction, or during Phaee 2, it will be considered grounds for a violation. It was observed that the contractor (Ames) was using steel baling wire to tie together solution collection pipes in the pregnant pond area. The solution collection pipes lie directly on the upper VLDPE liner in the pregnant pond. Tailing ends of the wire were protruding up to six inches from the pipes. In moat cases the tailing ends were pointed skyward, away from the liner, but in two places the wires were pointing down, toward the liner. Also, it was observed that loose pieces of wire were carelessly strewn about on the liner where they had been discarded during the pipe tying operations. Although the Division cannot fathom why steel wire would be selected for an application directly on a geomembrane, it ie unlikely that uncontrolled leaks will result. This is because: 1) I went around to each location where wire was used and picked up loose wire and tucked tailing ends into perforation holes on the pipes, and 2) if leaks develop in the upper liner of the pregnant pond area, from punctures caused by the wire or for any other reason, the fluid would be captured in the leak collection layer and pumped out. A number of the wire tie locations had been buried prior to Division inspection; the operator ie reminded that if unexpected quantities of fluid are found to be reporting to the leak collection layer during initial solution application, the operator will be required to excavate and repair any leaks. Piezometer location P1 was inspected. The actual piezometer installation was done in accordance with the specifications, including the incorporation of the Division's recommendation to backfill the protective pipe with silica sand, but the installation location for P1 was wrong. It seems that the installer ran short of cable, and as a result completed the installation at the extreme end of the available cable, which ended up below the lower anchor trench where the piezometer will do~no good. The operator will be submitting a specification change request to allow splicing of the piezometer cable eo that P1 can be properly relocated. Content of the specification change request was discussed, including.an aspect that the Division will require: a statement that traditional stand pipe piezometere will be installed if any of the vibrating wire piezometers should fail prior to providing sufficient information on hydrostatic head on the liner. The detour required to facilitate diversion channel culvert installation under Highway 67 was initiated on the evening of this date.