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necessary on occasion, and the discharges have been in compliance with applicable <br /> discharge permit effluent limits. <br /> Drainage and sediment control measures are addressed in Section 2.4.4 of the application <br /> text, as well as various exhibits and appendices referenced in the text. The following <br /> finding is made pursuant to the three small area exemptions referenced above. <br /> I. The Division granted small area exemptions (SAE's) from use of sediment <br /> ponds for the office facility area(SAE-1, .78 acres),the topsoil stockpile (SAE- <br /> 2, .39 acres), and the construction dirt stockpile (SAE-3, .30 acres) due to the <br /> limited size of the areas and due to the fact that the operator has demonstrated <br /> that ponds and treatment facilities are not necessary for the drainage to meet the <br /> effluent limitations of Rule 4.05.2 and applicable State and Federal water <br /> quality standards for receiving streams, and also due to the fact that no mixing <br /> of surface drainage with a discharge from underground workings will occur <br /> (4.05.2(3)(b)(i). <br /> B. Diversions, Conveyance of Overland Flow, and Stream Channel Diversions <br /> The segment of McClane Canyon affected by mine surface facilities extends <br /> approximately 3,000 feet from a box canyon at its upper end to its junction with East <br /> Salt Creek. Five tributary drainages come together at the upper end of the canyon to <br /> form the main ephemeral drainage. The mine portal facilities are situated at this <br /> location, and four of the five tributary drainages have been diverted via culverts <br /> beneath the mine bench. The culverts are adequately sized for the design event and <br /> have functioned well for over 25 years,with the exception of a couple occasions <br /> when they were overwhelmed by 100 year magnitude cloud burst type storm events <br /> in late summer. One ephemeral drainage on the south side of the portal bench is <br /> ditched around the shop building at the base of the cut slope, and is directed to the <br /> sedimentation pond. A temporary diversion ditch to the south of the sediment pond <br /> routes flow from three small ephemeral drainages around the pond, sediment drying <br /> area,topsoil stockpile and construction material stockpile. Berms in the office <br /> facilities area divert overland flow around the site. <br /> An additional diversion of the McClane Canyon stream channel occurred when the <br /> access/haul road was constructed in the spring of 1977. The point of diversion was <br /> between the riprap storage area and the office area,where the road was constructed <br /> across the channel. Due to the placement of road fill in the original channel, the flow <br /> in McClane drainage was diverted for many years. The diversion channel flowed <br /> generally straight west to East Salt Creek. Lower segments of the diversion channel <br /> developed into a steep sided gully, deeply incised into the colluvial/alluvial deposits, <br /> as is typical of ephemeral stream channels in the region. In 2006, Haul Road Culvert <br /> "P"was installed as approved by TR-14,which re-connected the upper segment of <br /> McClane Creek with its original lower segment. <br /> xv <br />