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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 />Upon final reclamation, all temporary diversion ditches, berms and culverts will be <br />removed, and ephemeral drainages will be reconstructed in their approximate <br />original locations. Fill embankments in locations where the haul road crosses <br />McClane Creek will be removed and the approximate original channel <br />configurations will be restored. <br />Diversion design is addressed in Sections 2.4.1 and 2.4.4 of the application. Channel <br />reconstruction is discussed in Section 3.5 of the application. Applicable maps and <br />tables are referenced in the cited text sections. <br />The following specific approval is required by Rule 4. <br />Rock riprap lining is proposed for use to control erosion in certain reclaimed <br />ephemeral stream channels. This measure is proposed to be approved by the <br />Division, since the riprap lining is necessary to control erosion, and the lined <br />channels will be stable and will require infrequent maintenance (4.05.4(2)(a)). <br />C. Sedimentation Ponds <br />There is one sedimentation pond at the mine, located between the portal bench area <br />and the office facilities area, on the south side of the haul road. The pond treats <br />runoff from the portal bench disturbed area, the upper segment of the haul road <br />surface and cut slopes, and a small supply storage area. The pond is somewhat <br />oversized (storage volume adequate to contain the sediment and runoff from multiple <br />10 year, 24 hour precipitation events below the level of the gated 8" primary <br />discharge pipe). In addition to the primary discharge pipe, the pond has an open <br />16