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1 <br />' The sides of the channel tapered up to the stripped foundation level at approximately 3:1 slopes. <br />SRK as-built Drawing No. 14711-1O5A depicts the approximate final slopes of the foundation with <br />approximately 1-ft of silt liner bedding added. Forty mil VLDPE liner was placed over the Type <br />3 liner bedding material. A network of 4-in diameter corrugated/perforated HDPE pipe with a <br />filter fabric sock was placed on 40-ft centers over the synthetic liner. Then a plus 3-fr deep layer <br />' of Type 1 drainage material was placed on the liner surface. The remainder of the sputter <br />embanlunent fill consisted of Type 4 (random fill material). <br />The random fill material was borrowed primarily from the northeast half of the lower impoundment. <br />The material was generally a clean gravelly sandy material. The material was excavated and placed <br />' using 631 CAT scrapers. Lift thicknesses were between 4 to 6 in. Vbratory smooth drum rollers <br />were used to compact the material in place. A method specification of 2 passes per lift with the <br />' vibratory smooth drum rollers were used to achieve compaction of the random fill materials <br />Five intake sumps were constructed and bedded in the sputter embanlQnent during the fill <br />' placement operations. The intake sumps wnsist of 36 in diameter corrugated metal pipes buried <br />vertically in the fill Approximately 10-ft above the sump invert a 10-in diameter HDPE, SDR-11 <br />' pipe runs horizontally at approximately a 1 percent slope to the face of the sputter embankment. <br />At the sputter embankment the 10 in fIDPE pipe ties into a 10 in diameter steel pipe which in turn <br />is attached to a steel decant channel 'Ilse decant channel runs up the face of the sputter <br />' embanlrntent slopes and will be used to decant water from the impoundment surface. SRK as-built <br />Drawing No. 14711-113 shows details of the intake sumps and locations and elevations of the <br />' features. <br />The water return pumps and pipelines were not under this contract and details of these pumps and <br />pipelines may be located in the Minproc drawings. <br />' 33 Collection Pond <br />The wlledion pond couects the tailings seepage water from the impoundment synthetic liner <br />' system. The seepage water is returned to the upper or lower impoundment surface water ponds <br />for recycling to the mill. The pond is located approximately 20&ft downstream of the main <br />' embanlanent tce and is directly connected to the impoundment foundation liner by means of the <br />collection channel The pond crest is approximately 340-ft squaze. The average depth of the pond <br />' is approximately 19.5-ft deep with 3:1 slopes. The ponds maximum holding capacity is <br />approximately lOS million gallons. The pond has a double synthetic liner system with a leak <br />detection system. A water return sump and leak detection sump are located in the southeast corner <br />' of the pond. <br />' 12 <br />1 <br />