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optimum. Construction engineer will be on site to provide testing during fill placement and verify <br />compaction of floor of pond by number of tests recommended by CTL Thompson._ CTL/Thompson, Inc. <br />has conducted -slope stability analysis on the TSF embankments as shown in Exhibit TSF -02 and TSF -03. <br />Samples were collected from drilling two (2) additional holes to verify and confirm the 1990 permeability <br />test hole data and additionally confirm the embankment materials and underlying soils. Additionally, a <br />sample of tailings materials generated from laboratory testing was analyzed. The embankment materials, <br />native soils and tailings materials were tested for strength and classification, using direct shear tests for <br />use in analyzing slope stability of the embankment. The results of the CTL Thompson Letter Report of <br />July 8, 2011, are presented as Appendix A, Slope Stability Evaluation Tailings Pond Embankment and <br />Future Tailing Slope, July 8, 2011. Subsequently, CTL Thompson issued an update to the July 8, 2011 <br />Report, presented as Appendix B, Slope Stability Evaluation Tailings Pond Embankment and Future <br />Tailing Slope, August 17, 2011. <br />Phase 1 TSF reconstruction and Phase 2 new construction will use similar construction techniques and <br />methods. The Phase 3 expansion lifts, will additionally use typical cyclone placement of select coarse <br />material on the inside of the expansion embankments for increased stability. <br />Geu,soithetic Clay Liner <br />A Bentomat " DN gco,}nthetic clay 12ffi fi, i elaj, HAdef- liner, or equivalent, is placed on the <br />interior slopes and impoundment bottom_. <br />.Thc gco,�nthetic clay liner is <br />installed concurrent with the leaf. detection drainage net ,�,tcni and the 45 -mil polypropylene <br />geomembrane liner. <br />Geosynthetic clad liner spccifications are presented in Figure C -4, Bentomat'" DN <br />Leak Detection System <br />Concurrent with theFel• &A4iig installation of the geo,ynthetic clay liner, a seepage /leak detection system <br />iti 1n lied between the geo,ynthcuc clay layer and the synthetic liner with the collection system located in <br />the northwest corner of the impoundment, and the impoundment bottom sloping at i /2% slope to the <br />northwest. <br />Exhibit TSF -05 shows additional details on the leak collection system and sump. The leak detection' - Formatted: Space Before: 12 pt <br />system is concurrcntly installed betweenle.el the top ]Liyer4ft of the 2 6 nfi lifts-ol 1 x 10-6 cm/s or <br />less) coos }nthetic clay L and &ic -te the ifi talla'•afi o the 45-mil polypropylene geomembrane liner. <br />The leak detection system is a ,vielt Elfaiii systenicomposite drainage product, produced b} thermally <br />laminating a 6oz /y1; nonwo%cn geotextile to hoth side, of a polyethylene drainage net capable of Formatted: Superscript <br />intercepting liquid within the leak detection zone and conveying the liquid to a collection sump for <br />storage. The wiel, drain is 12-aide, 1 ineh thiek. eh a in the !2.i eky liner 5014 <br />ii' is laid Hai a leak detection drainage net system is shown on Exhibit TSF -05 and Exhibit TSF - <br />06. <br />The volume of the collection system is limited to the sump and is approximately 90 gallons. The sump is <br />accessed through a 4in PVC pipe to the top of the impoundment. Collected leachate will be returned to <br />the TSF and then recycled to the mill through the impoundment decant pump(s). The leak detection <br />system requires a manual inspection of the sump through the 4in PVC pipe. If leachate is detected <br />(indicating a leak in the 45-mil polypropylene), the level will be monitored, a small pump will be installed <br />N11990 -057 1lav 14, 201 3 , <br />Formatted: Space Before: 12 pt, After: 12 pt, <br />Don't keep with next <br />Formatted: Font. 10 pt, Bold <br />Formatted: Right <br />Formatted: Font: 10 pt, Bold <br />i <br />