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<br />7. Rule 6.4.4 - Exhibit D -Mining Plan - <br />a) the mining method for the limestone spoils is clearly described. However, there are still a <br />couple of questions which need answered: l) will th~ee~ntire spoils pile be removed? 2) <br />what removal method will the applicant utilize to prevent spoils material from entering the <br />~ ~ drainage system in that part of the pile which abuts the creek? 3) if the entire spoils pile is <br />removed will the eastern excavated areas of the pile require any significant grading to <br />establish low gradient stable slopes? <br />c) Pursuant to Rule 3.1.5(3), all grading shall be done in a manner to control erosion and <br />siltation of the affected lands and to protect areas outside the affected land from slides and <br />other damage. Also, pursuant to Rule 3.1.6, disturbances to the prevailing hydrologic <br />balance of the affected land and of the surrounding area and to the quantity or quality of <br />water in surface and groundwater systems both during and after the mining operation and <br />during reclamation shall be minimized. Currently, under an existing 1 l0 permit, CLC is <br />required to construct "toe ditches", sediment ponds and hay dams below the spoils pile to <br />trap sediment so siltation of the South Arkansas River will not occur. Will CLC commit to <br />this method of erosion control or will CLC propose another control method to prevent <br />siltation of the adjoining waterway? Either way, the erosion control system must be <br />adequately described in this document (construction details, specifications, etc.) since this <br />is a stand alone permit. <br />If retention ponds are included in the Stormwater Management Plan (SWMP) they must <br />be sufficiently sized to contain the 2 year - 24 hour precipitation event. If a SWMP is not <br />required, the retention (sedimentation) ponds must be sized to contain the 10 year - 24 hour <br />precipitation event (DMG policy). The ponds must be adequately constructed to convey of <br />excess runoff during upset conditions (precipitation events greater than the designed event). <br />This would include a primary spillway system (or drop tube structure). The ponds need to <br />be strategically located so all of the sediment laden runoff from the entire watershed can be <br />captured and retained on site (the watershed is defined as the permit area and that area <br />~, upgradient of the permit area which will contribute runoff that will travel across the <br />~' U <br />` affected land area). Berms, diversion ditches or other methods (culverts etc.) can be utilized <br />to direct runoff to the ponds. The location of the ponds, berms, diversion ditches, etc., must <br />be shown on the various exhibit maps and the construction specifications must be included <br />in the Mining Plan. <br />a) Mining in the limestone area will consist of a blast and bench method. The height of the <br />bench is proposed to be 50 feet. What is the width of the bench, or benches? <br />Prior to mining the limestone deposit, the applicant proposes to remove the overlying <br />overburden and temporarily stockpile it at a location within the permit area. Where will the <br />r' overburden be moved to (needs to be shown on the Mining Plan map)? How much <br />overburden material will the applicant stockpile? <br />The applicant proposes to process and stockpile the limestone product material on-site. <br />Where will the equipment and stockpile(s) be located? The location of the equipment and <br />~ stockpile(s) must be shown on the Mining Plan map. <br />