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The Division proposes to grant three (3) small area exemptions <br />from use of sediment ponds during the operating life of the mine. <br />The Division approved these exemptions due to the limited size of <br />the area and due to the fact that ponds and treatment facilities <br />are not necessary for the drainage to meet the effluent limita- <br />tions of Rule 4.05.2 and applicable State and Federal water <br />quality standards for receiving streams, and also due to the fact <br />that no mixing of surface drainage with a discharge from <br />underground workings will occur. The exemption areas are located <br />in the service area on the fan shaft level, on the bath house <br />level, and in the area surrounding the powder magazine <br />(4.05.2 (3) (b) (i)) . <br />However, with the approval of pond removal, these small area <br />exemptions are no longer applicable. <br />B. Diversions and Conveyance of Overland Flow <br />Sediment control ditches have been designed and constructed in <br />compliance with Rule 4.05.3. Locations are shown on Map <br />2.05.3(4)-2a, Post Reclamation Drainage System Map. <br />C. Stream Channel Diversions. <br />The major drainage channel, which carries irrigation backwater to <br />the Carbon Ditch, was reconstructed to approximately the contours <br />shown on Map 2.05.4(2)(c)-1. Rip-rap, sized at 9-12 inches, was <br />placed in the channel and up the sides of the channel. Cross <br />sections of the channel can be found on Drawing 2.04 .4 (2)(c)-1, <br />and 2.04 .4(2)(c)-2. <br />The lower portion of this major drainage channel will be <br />relocated, after the sediment pond is removed, so that it flows <br />into the bottom of the draw. This portion will be constructed in <br />the same manner as the entire channel, except no berms will be <br />constructed to stop drainage from entering the channel from <br />surrounding areas. <br />Sedimentation Ponds <br />The Red Canyon Mine has one sediment pond on site. The pond has <br />been designed, constructed, and maintained in accordance with the <br />requirements of 4.05.6 and 4.05.9. The location of this pond is <br />shown on Mag 2.05.3(4)-2a, Poet Reclamation Drainage System Map. <br />The pond is located as near as possible to the disturbed area and <br />is not located within perennial streams according to <br />5.05.6 (1) (6) . <br />Acid-forming and Toxic-forming Spoil <br />Pre-law spoil material was utilized to achieve the post-mining <br />topography and cover the underground development waste pile with <br />four feet of cover. A 1988 renewal adequacy issue concerned the <br />validity of the use of two chemical analyses of pre-law spoil <br />samples which had been taken from the top four inches (4°) and <br />showed no elevated parameter levels. The operator sampled three <br />additional sites, compositing the top three feet of material. <br />One of these samples had a pH of 4.6 and an electrical <br />conductivity of 4150 umhos/cm. The results of this testing led <br />to the Divisions request that the operator develop a plan to <br />mitigate the presence of acid-forming spoil on the regraded <br />surface. <br />12 <br />