2011-03-18_PERMIT FILE - C1981044A (4)

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rangeland/wildlife area at the former No. SA portal area, and the rangeland/wildlife areas at the former refuse pile. The majority of these roads are former haul roads and county roads vacated to EC. The roads will be adequate to support the post-mining land uses. Ponds Impoundments, and Diversions EC has designed and constructed a system of ponds, ditches, and embankments to retain runoff from its disturbed areas throughout the mining operation. Each pond and structure was designed and constructed under the supervision of a qualified, registered professional engineer. All ponds, ditches, and culverts were designed by Mineral Resources and Engineering, Inc. The general system layout is shown on the Drainage and Sediment Control Map (Map 26) which presents a total of 23 dams or embankments which were constructed to control runoff from disturbed areas or to serve as settling ponds for mine discharge water. A series of ditches and culverts were designed as a part of this system to convey, transfer, and gather the runoff. Each sedimentation pond has been designed for the 10 year/24 hour precipitation event and to meet all requirements under the performance standards of Section 4.05 Hydrologic Balance. The design methodology and design calculations used for all ponds, ditches, culverts, and the bridge crossing the Williams Fork River are included in Exhibit 18, Drainage and Sediment Control Plan. Pond 9A-Pl is planned as the only permanent impoundment under this permit. All of the sediment ponds, excluding the treatment facilities (No. 5 and 9 dewatering system and waste water treatment system), are dewatered manually. This process requires visual inspection of the ponds during the runoff season or after significant precipitation events. The pond inspection during this period includes observing water elevation in relation to discharge structure elevation. If the water elevation is higher than [he discharge structure elevation the gate is opened and the pond allowed to dewater to the invert of the discharge structure. The gate is closed and the pond readied to accept the next runoff event. At the time the pond is dewatered water samples are taken in accordance with the discharge permit requirement. Typically only the HR pond and 9A-Pl discharge during the spring runoff period or in response to major thunderstorms. As shown in Exhibit 18 (page 13 and on Map DWG IV-42) Pond 9A-Pl does not meet the size requirements of 4.05.9 (3) but is adequately designed to serve as a stock pond which is its intended post-mine land use. Nine (9) years of pond inspections from 1983 to 1991 show that the pond is adequate for its intended use. Pond 9A-Pl normally fills in March, containing an average of 5.0 ac. ft. of water (range 0.7 to 7.5 ac. ft.) and then dries up in late July or August. This is a valuable source of water for spring and early summer livestock grazing. Furthermore, i[ is the only accessible water on this property. Pond 9A-Pl has only discharged once during the last eight years. This discharge was sampled 3/13/90 and test results show that the quality is adequate for the intended use and will meet State and Federal water quality standards: ph 7.3, E.D. 86.8 t 25° C, oil and grease 0, TDS 94 mg/1, and Settleable Solids < 0.2 mUl/hr. EC will survey Pond 9A-Pl immediately prior to final bond release, and if the survey shows any significant build-up of sediment, the pond will be cleaned. Topsoil Nearly all surface disturbance activities at the EC operation have been completed. In isolated instances where surface disturbance may occur, all available A and B soil horizons will be salvaged as one product due to the small acreages involved. In areas where minor disturbances occur involving light truck or other equipment usage, topsoil may not be removed if gathering of the topsoil would create a greater disturbance than the disturbance itself. In areas subjected to occasional traffic, the ground will be scarified and planted according to the approved seed mixture presented in Section 2.05.4 Reclamation Plan. Permit Revision 04-34 2.05-19 Revised 7/2/04