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3.0 LINER SYSTEM INSPECTION AND TESTING <br /> Liner system inspection will consist of a two-staged effort to: (1) initially and qualitatively identify <br /> the location(s) and type(s) of potential liner damage, if any, followed by (2) a quantitative <br /> assessment of the lateral and vertical extent of such damage locations to develop sufficient <br /> information, upon which repair, replace, or(potentially) closure options can be evaluated. <br /> As detailed in Exhibit C of the approved DRMS Permit M2009-076 (and as per the certified "as- <br /> built" configuration), the composite liner system provided and installed by Colorado Lining <br /> International for the Hukill Mill Site EPF consists of the following individual components (listed <br /> from lowermost to uppermost): <br /> • Bentomat DN Geosynthetic Clay Liner <br /> - a self-healing layer of sodium bentonite sandwiched between two nonwoven geotextiles <br /> needle-punched together, with a hydraulic conductivity of 5 x 10-9 cm/sec <br /> • HDPE Geomembrane (Textured) <br /> - a chemically resistant, UV stable 60 mil high density polyethylene (HDPE) geomembrane <br /> with a textured surface on both sides <br /> • Geotextile Drainage Layer <br /> - a geocomposite drainage layer incorporating an HDPE grid (to facilitate lateral drainage) <br /> sandwiched between two 6 oz/yd2 nonwoven geotextile layers. <br /> VRI anticipates that there may be significant to extensive ultra-violet (UV) degradation and/or <br /> wind-induced damage to the topmost non-woven geotextile encapsulating portion of the upper <br /> geocomposite drainage layer. This damage potential, in fact, was the determinative reason for <br /> VRI's Fall 2015 placement of the non-authorized waste rock and weathered rock material, an <br /> action undertaken to minimize the exposed surface area and to prevent further ultra-violet and/or <br /> wind-induced damage to the exposed liner surface. VRI anticipates the likelihood of further or <br /> incremental damage to this liner component (to be introduced via equipment contact); although, <br /> all removal action efforts will be undertaken in a manner that minimizes such potential. <br /> 3.1 Visual Inspection and Assessment <br /> With the exposed liner system having been made readily observable as a result of the removal of <br /> overlying waste rock materials, etc. followed by the fine cleaning (refer to Section 2.0, above), <br /> VRI will complete a visual assessment of the full areal extent of the liner system, specifically <br /> observing for indications of ruptured or severed grid components and/or significant indentations <br /> indicative of concentrated impact loading or sharp/angular rock penetration, etc. <br /> 3.1.1 Damage Report <br /> Any visibly ruptured or tom area, and any area exhibiting significant indentation (i.e., exhibiting <br /> non-rebounded vertical depth distortion greater than 2-inches) will be demarcated by orange <br /> 12 <br />