2010-03-18_REVISION - M1977285 (6)

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Response to DBMS Comments Environmenfa/Prolectlon Plan Denison SundayMhes Group ¦ LLDPE is more resistant than PVC to puncture from burrowing animals; however, this should not be of concern due to the active surface operations at the mines and the lack of vegetation within the vicinity of the ore storage pads. ¦ Similar to LLDPE, PVC has high puncture strength and excellent abrasion resistance (Colorado Lining 2010). ¦ LLDPE would require field seaming and quality assurance/ quality control (QA/QC) field tests of the seams. PVC liner for the relatively small ore pads can be seamed and tested by the manufacturer providing excellent QA/QC. For these reasons, Denison prefers the use of a 30-mil PVC liner for ore pad construction. Comment 4 Ore Paa"17slallalion. The Division generally accepts Denison's proposed plan. To clam andlor reiterate, the following comments are included herein. Surface preparation prior to liner deployment will include the placement, grading and compaction of the soil substrate such that it produces a smooth surface on which to bed the liner. The soil substrate should be screened, placed, and compacted as proposed. The compaction of the soil substrate should be tested once for every ore pad liner installed to verify adequate compaction of material (per manufacturer's liner requirements). All bedding material will be visually inspected prior to liner deployment, and all particles larger than 318 inch, or other angular or protruding materials, must be removed to maintain integrity of the liner. The anchor trench along the perimeter of each geo-membrane must be a minimum of 1 foot deep and I foot wide; 2 feet deep and 2 feet wide is preferable. A perimeter berm must be included to prevent runoff and runon, yet must be traversable by equipment and not allow damage to the liner. The anchor trench should be located at least afoot outside the crest of the berm. Trench backfill materials must be adequately compacted. The liner cannot be deployed when temperatures are below 35 degrees F, or when this is precipitation (or per manufacturer's recommendations, whichever is more conservative). Liner material will be covered to a depth of at least 1 foot of clean and screened earthen fill, to be placed and spread as proposed. All preparation and installation must proceed according to the approved plan, and overseen and documented by qualified onsite QC monitor, who, per Hard RocklMetals Rules, must be a Colorado registered PE. Response Agreed. These requirements are addressed in the ore storage pad specifications. Comment 5 Ore PadTeslllic, andCerli?calion All liner deployment QA1QC will include trial seam testing, field seam testing (pressure testing), and destructive testing (at a location selected by the QC monitor). Destructive testing of the field seamed geo-membrane will be approximately 24 inches along the seam and 12 inches across the seam, one sample each day or every 500 feet along the seams. 0 Final Sunday Mines RTC_v2.doc