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Mr. Michael Cunningham <br />CDRMS <br />November 26, 2013 <br />prior to discharge into the TSF and specify how and at what point the pH will be <br />measured. The Division will require the tailings in the TSF to have a pH between 6.5 and <br />9 and the Operator will be required to demonstrate that the tailings are with the required <br />pH range prior to final reclamation of the TSF. <br />Response: <br />pH will be maintained in the grinding circuit, as proper pH is requisite for the subsequent <br />flotation process. New paragraphs will be added to Section 4.2.3, Grinding Circuit as <br />follows: <br />"Maintaining a slight basic pH is critical to successful recovery in the milling <br />process. Lime will be added to the ball mill via a feeder system to achieve <br />the ore -type specific pH requirement, which is typically in the range of 8 -9. <br />pH will be tested in the conditioning tank, which is also part of the grinding <br />circuit to assure proper pH prior to flotation. If necessary, additional lime can <br />also be added at the conditioning tank. Once the desired pH is achieved all <br />downstream process flows (concentrates and tailings) will maintain this pH <br />level. <br />pH will be tested monthly in the TSF to assure that pH levels between 6.5 <br />and 9 are maintained at all times. Lime will be added to the TSF should pH <br />levels drop below 6.5. Given that only sulfide ores are processed, it is not <br />anticipated that pH levels will exceed the pH 9 threshold limit. In the unlikely <br />event of a pH greater than 9, UMC will reduce the amount of lime introduced <br />into the process. <br />pH testing will be performed on the TSF to assure the proper pH range prior <br />to final reclamation. <br />16. Please describe the activities that will be conducted in the laboratory. <br />Response: <br />Laboratory activities will include bulk density, screening, flotation, and thickening test. A <br />Marcy bulk density scale will be used for bulk density testing. Both wet and dry <br />screening will take place in the laboratory. Samples for screen test will be crushed and <br />ground with laboratory scale equipment. Wet screen material will be dried in a <br />microwave oven. Neither the bulk density nor screen tests require the use of reagents. <br />Flotation test will be conducted to optimize the flotation process. Samples ranging from <br />50 -100g will be floated using small quantities of reagents already on site. After testing, <br />float samples will be reintroduced into the process. <br />Thickening test will be conducted using small amounts of environmentally friendly <br />polyacrylactes. <br />Sample preparation will also be performed in the laboratory. <br />6.3.4 Exhibit D - Reclamation Plan <br />17. The proposed reclamation seed mix only includes grass species. The Division believes <br />