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Response to DRMS COn7177entS <br />Enuironmenla/Profecfion P/an, <br />Denison Van 4Mine <br />¦ LLDPE would require field seaming and quality assurance/ quality <br />control (QA/QC) field tests of the seams. PVC liner for the relatively <br />small ore pads can be seamed and tested by the manufacturer <br />providing excellent QA/QC. <br />For these reasons, Denison prefers the use of a 30-mil PVC liner for ore <br />pad construction. <br />Comment 4 Ore Padlnstallation The Division generally accepts Denison's proposed plan. <br />To clarify and/or reiterate, the following comments are included herein. Surface <br />preparation prior to liner deployment will include the placement, grading and <br />compaction of the soil substrate such that it produces a smooth surface on which <br />to bed the liner. The soil substrate should be screened, placed, and compacted as <br />proposed. The compaction of the soil substrate should be tested once for every <br />ore pad liner installed to verify adequate compaction of material (per <br />manufacturer's liner requirements). All bedding material will be visually <br />inspected prior to liner deployment, and all particles larger than 318 inch, or <br />other angular or protruding materials, must be removed to maintain integrity of <br />the liner. The anchor trench along the perimeter of each geo-membrane must be <br />a minimum of ]foot deep and ]foot wide; 2 feet deep and 2 feet wide is <br />preferable. A perimeter berm must be included to prevent runoff and runon, yet <br />must be traversable by equipment and not allow. damage to the liner. The anchor <br />trench should be located at least afoot outside the crest of the berm. Trench <br />backfill materials must be adequately compacted. The liner cannot be deployed <br />when temperatures are below 35 degrees F, or when this is precipitation (or per <br />manufacturer's recommendations, whichever is more conservative). Liner <br />material will be covered to a depth of at least I foot of clean and screened <br />earthen fill, to be placed and spread as proposed. All preparation and <br />installation must proceed according to the approved plan, and overseen and <br />documented by qualified onsite QC monitor, who, per Hard RocklMetals Rules, <br />must be a Colorado registered PE. <br />Response Agreed. These requirements are addressed in the ore storage pad <br />specifications. <br />Comment 5 Ore Pad TesMwand Certi rcation All liner deployment QA/QC will include <br />trial seam testing, field seam testing (pressure testing), and destructive testing (at <br />a location selected by the QC monitor). Destructive testing of the field seamed <br />geo-membrane will be approximately 24 inches along the seam and 12 inches <br />across the seam, one sample each day or every 500 feet along the seams. <br />Response PVC liner will be utilized and liner seams will be completed by the <br />manufacturer to provide a complete panel for installation; the seams will <br />be tested in accordance with the manufacturers' QA/QC policy. In <br />particular, destructive tests will be performed to verify that the seam <br />strength requirements of the specifications are met. In addition, thickness, <br />bond seam strength (shear strength), and peel adhesion quality assurance <br />tests will be performed. Copies of the QA/QC documentation will be <br />Final Van 4 RTC v2 Letter.doc