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mixing, and 3) curing for a minimum of eight hours. No wetting, mechanical mixing, or <br /> curing will occur in the proposed process so as not to produce cohesive pellets. <br /> The current conveyor system does not have equipment in place (nor is this TR proposing to <br /> install such equipment) to be able to agglomerate ore and cement. Ratios for tailings <br /> agglomeration were never outlined in the approved Amendment 10 Application as ratio <br /> flexibility was required to allow for necessary adjustments to be made for successful <br /> agglomeration to occur, depending on variabilities in ore types at any given time. <br /> Section B.1 Composition of Concrete of the Holcim Technical Manual (Manual), which <br /> includes components and mixing ratios for concrete, is included in Attachment 1. As stated <br /> on page 20 of the Manual, "Aggregates occupy 60-75% of the concrete(measured by weight <br /> or by volume, as Fig I.15 and they are important constituents from a technical and <br /> economical point of view. Aggregates play a central role in concrete strength and <br /> durability).... The dominant component in concrete is clearly cement and the cement paste <br /> is fundamental in defining many concrete characteristics (workability, strength, production <br /> cost, and durability)." Based on this information, concrete will not form at the proposed <br /> ratio of cement to ore(less than 0.7 percent). <br /> Additionally, general ratios for concrete mixes are included in the below table. These ratios <br /> are included in the Commercial Grade Quickrete Portland Cement Installation Guide as <br /> Attachment 2. <br /> Type Parts Quickrete Parts Sand Parts Gravel <br /> yp Portland Cement <br /> Concrete Mix 1 2 3 <br /> Since no concrete will form at the proposed mixing rate and mode,the proposed change will <br /> not create impermeable zones or impair rinsing of the VLFs leading to closure. <br /> 2. Potential for impact on VLF slope stability: When the DRMS approved placement of <br /> agglomerated mill tailings on the VLFs, CC&V committed to mixing agglomerated tailings <br /> (clarified in TR-103 as one part tailings to 9 parts crushed ore)prior to the final placement on <br /> the VLF and not placing agglomerated tailings on the outslopes of the VLF. The TR-111 request <br /> states, "no anticipated impacts to the stability... during operations or closure are anticipated. <br /> The proposed cement addition is intended for buffering capacity only." Despite the intent to <br /> affect only the buffering capacity,please provide additional rationale as to why the geotechnical <br /> properties of the placed ore will not be altered with the substitution of cement. <br /> Geotechnical properties of the placed ore will not be altered with the substitution of cement <br /> because the proposed ratio of cement to ore cannot form concrete. This is based on mixing <br /> ratios outlined in Attachment 1. CC&V remains committed to all parameters as defined in <br /> TR 103. <br /> 3. Potential for cemented fines downward migration: The DRMS has had previous concerns related <br /> to fines from the HGM tailings migrating to the VLF liner and interfering with both drainage and <br /> puncturing of the liner for closure. Please address the potential for cement fines migrating to the <br /> liner and forming a "hard"barrier to interfere with puncturing the liner at closure. <br />