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A statement that changes to the designs will be submitted to the Division has been <br />added to the signed engineer statement in Appendix 12. <br />2. Pursuant to Rules 6.4.21(15) and 73. 1, the construction of the EPFs must proceed <br />according to a sequence and schedule, with all steps documented by the operator, <br />installation certified by a licensed PE, and all critical steps inspected by this office. The <br />installation schedule is especially important concerning the synthetic materials to be <br />used as liners and as conveyance structures, in the context of the elevation and climate <br />conditions of the site. Please provide acknowledgement from you or the operator that <br />commits to limiting time of construction so as to conform to manufacturer's product use <br />and installation recommendations. <br />The operator and /or on -site engineer commits to limiting the time of construction so as to <br />conform to the manufacturer's product use and installation recommendations. This is <br />stated in Appendix 12. All manufacturer's installation procedures are enclosed in <br />Appendix 14. <br />3. Please also provide commitment to inform the Division of the construction schedule so <br />that the necessary inspections may be performed in a timely manner. <br />A more detailed description of the construction phases has been provided in Appendix <br />12. The applicant also commits to informing the DRMS about construction timelines. <br />The applicant will provide the DRMS with sufficient notice prior to construction phases to <br />allow for DRMS inspection if so desired. <br />4. A primary feature of the plan is the use of two separate lined ponds: the leach field and <br />the mine water pond. The liners are to extend up to the elevation of the surrounding <br />grade. A brief description of the anchoring of the mine water pond is provided in the <br />text, and the Division finds this method adequate for this use. However there is nothing <br />included for the anchoring detail of the EPDM leach field liner. The Division agrees that <br />each of the liners must be anchored, but the anchor details of the leach field liner must <br />be provided. <br />The anchoring will be used for the leach field installation as well. It has been <br />described in the Leach Field Design section of Appendix 12. <br />5. Part 8 of the plan states that the leach field area "may be" lined with a specific EPDM <br />membrane with filter fabric on both sides. It is not clear from the text which feature of <br />the liner structure (e.g., the thickness, the filter fabric, or the use of the liner itself) may or <br />may not be used. This office considers the EPDM to be a suitable liner material, the 45- <br />mil thickness to be appropriate for this use, and the 0.25 inch felt layers on each side to <br />be essential. Please revise this part of the plan to reflect a commitment to employ these <br />features in the design. <br />The statement had been edited to indicate the leach field will be lined. <br />6. The liner for the mine water pond is to be 45 -mil polypropylene with a 0.25 -inch felt layer <br />underneath, presumably to protect it from rock puncture. The underlying layer is to be <br />created out of existing waste rock, which lends its strength to the internal angle of friction <br />of the angular rock. Even though this pond will not be loaded with rock, the Division is <br />