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cross-sections are provided in Figure 2.05.3-16. Support design documentation are <br />provided in Exhibit 15. <br />Ditches will be variously armored with riprap or equivalent protection against erosive <br />velocities. Rip -rap installations will utilize woven or nonwoven geotextiles on a coarse <br />sand base of at least three inches in thickness for a filter blanket. The geotextiles will <br />have an EOS of 70 or less. <br />Ditch D-20 (Map 2.05.3-7) reports to Pond 6. Temporary straw or rock check -dams will <br />be placed along it above Pond 6 to control flow -velocity and reduce sediment loading <br />reporting to Pond 6. As vegetation becomes more established on the slopes above <br />pond 6, these check dams will either be removed, or if well vegetated, left in place for <br />post mining wildlife habitat. <br />Clean out of pond 9 will require a small area located directly upslope from the pond to <br />be used for sediment dewatering (Figure 2.05.3-14c). Top soil will be stripped from the <br />area and used to form a temporary berm upslope of the drying area. Sediment will be <br />removed from the pond and transported to this area for drying. The material will be <br />spread and turned as necessary to facilitate drying,, The dried sediment will be <br />transported to areas of mine reclamation to be used, as determined by soil analysis, as <br />either soil or cover material. Upon project completion, the top soil berm will be respread <br />over the drying area followed by seeding and mulching as per Section 2.05-4. <br />Diversions are designed, constructed and maintained to minimize adverse impacts to <br />the hydrologic balance. Placement will not increase the potential for slides or <br />downstream flooding, nor endanger property or public safety. Diversions will be <br />maintained to prevent additional contributions of suspended solids to stream flow and to <br />runoff outside the permit area to the extent possible, using the best technology currently <br />available. This will be accomplished with measures that include but are not limited to <br />the maintenance of appropriate gradients, the use of various channel linings, <br />revegetation, roughness, structures, energy dissipaters and detention basins. <br />Variance from Rule 4.05.18 (Stream Buffer Zones) <br />The topography beneath fills 5, 6 and 7 necessitated locating sediment ponds 5, 6 and <br />07a partially within the 100 foot stream buffer zone required by Rule 4.05.18. Therefore <br />Lorencito Coal Company has requested a variance from that requirement for these <br />three sediment ponds. The only activities within the stream buffer zone will be the <br />construction and maintenance of these ponds. <br />RN -4 Page 2.05-30a November 3, 2017 <br />