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<br />- Measurements were made using the top of the mold as a datum to define the slope <br />of the compacted soil liner surface prior to loading. Figure 2 depicts the <br />measurements and location of the measurements taken on the surface of the soil <br />liner. <br />- Two small holes were excavated in the surface of the prepared soil liner fill for <br />placement of the two 2-inch gravel pieces. One gravel piece was placed in the <br />hole excavated on the sloping soil liner and the other gravel piece was placed in <br />the hole excavated on the flatter portion of the soil liner. The gravel pieces were <br />placed so that the "flat" face was up and exposed on the surface similar to the <br />manner in which it occurred on the rolled soil liner surface on the valley leach <br />pad. Excavated material was placed and compacted around the two rocks as <br />much as possible when filling the over-excavated hole. <br />- A specimen of the 80-mil VLDPE was cut and placed on the soil liner surface <br />containing the gravel pieces. <br />- Approximately 6-inches of liner cover fill were placed over the geomembrane and <br />tamped to simulate a condition that will exist following placement of the liner <br />cover fill on the heap leach pad. <br />- The loading plate was placed and leveled on the liner cover fill. The assembly <br />of the loading apparatus was completed. <br />- The loads were applied in 100 psi/hour increments until a maximum load of 300 <br />psi was obtained, The load was left on overnight for approximately 16 hours. <br />- The cell was disassembled, and the VLDPE specimen was examined both visually <br />and employing a modified vacuum box to detect punctures. The vacuum test <br />apparatus consisted of a clear Pyrex funnel which was inverted on the surface of <br />the geomembrane and connected to a regulated vacuum source. The vacuum was <br />set at 15-inches of mercury, approximately twice that of 8-inches recommended <br />in the ASTM D4545 procedure. <br />Observations: <br />80 MIL VLDPE GEOMEMBRANE <br />Upon extraction of the liner cover fill from the mold, the VLDPE was moderately distressed and <br />scarred from the drain cover fill. The deepest scars appeared to be approximately 10 mils deep. <br />The scars on the top side of the geomembrane did not appear to be any deeper over the [wo 2- <br />inch gravel pieces than over the rest of the soil liner fill. The bottom side of the geomembrane <br />showed minimal distress after the test. One of the 2-inch gravel pieces left a minimal <br />impression in the geomembrane but it is not evident from further examination of the <br />3 <br />