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1.2. Sediment Control System for Gold Operation <br />~~ The permit azea is basically divided into 2 areas, the northern azea that drains into Pond A, and the <br />southern azea that will drain into newly constructed Ponds #1 and #2. <br />The gold mining operation will control sedunent through a number of measures. First, the 8' berm <br />created on the west side of the permit area next to the ROW of Highway 9 will channel atl runoff <br />from any disturbed areas into two sediment ponds located at the southeast wmer of the permit area. <br />This is also the low point of the permit area. Water will enter Pond #1 which will then flow into <br />Pond #2. Pond #1 will serve as the cleanout pond, while Pond #2 will serve to collect runoff from a <br />100 yeaz event, although much of this flow will be captured in either Pond A (below the prep plant) <br />or the active mining pits. A third pond, Pond #3, will be installed to handle pumped water from the <br />active mining pit. It will then feed Pond #4, which will allow the clean water to seep back into the <br />ground, thus avoiding a dischazge from the site. No runoff from the site will be allowed to enter <br />ponds #3 and #4. <br />The 8' high berm will have a maximum 2.OH1.OV and will be created from the existing disturbed <br />~+ gravel on the site. Topsoil may also be used to create the bens on the southern portion of the mining <br />azea if excess topsoil is available from stripping. In all cases, gravel and topsoii will not be mixed to <br />create the berm. A ditch of 2.0 feet depth and 2H:1V sideslopes (Collection Ditch #1) will be <br />constructed on the west side of the berm to duect all disturbed area flows into Pond #1, then Pond <br />#2. This ditch will cross access roads in two locations as shown on Map C-2, where a 18" culvert <br />will be placed in the ditch for the road crossing. <br />The terrain rises to the east from the permit azea, but the Columbia #1 Ditch is located near the east <br />permit boundary and this ditch prevents any undisturbed runoff from entering the site. See Map C- <br />2. <br />Sediment Pond #1 is simply a sediment cleanout pond and will not be used for detention volume. <br />Sediment Pond #2 will handle the runoff from the majority of the gold mining azea. Pond A will <br />handle runoff from the prep plant azea as well as from the main gravel operation. Map C-4 shows <br />the drainage areas for the site in addition to all ditches, berms and ponds. <br />Alma Placer 7/03 13 <br />