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constructing a sediment pond is not warranted. Sediment contributions from the small disturbed area can effectively be <br />controlled using the stated Best Management Practices (BMP's), and therefore falls under a n SAE, consistent with <br />applicable provisions of Rule 4.05.2(3)(b). The will be no discharge or mixing of mine water with surface drainage <br />from the site. Given the limited site area, agravel-surfaced pad area, the drainage and sediment control measwes, and <br />. the effectiveness of the BMP's in reducing peak settleable solids concentrations to 0.23 m]/1 (modeled results), TCC <br />submits that an SAE is justified for this site. The estimated peak flow and runoff from the site for the 10-year, 24-how <br />storm event is 1.52 cfs and 0.17 acre-feet, respectively. The peak settleable concentration in the runoff from the <br />proposed Bleeder Shaft pad azea is less than natural settleable solids concentrations for nmoff from undistwbed lands, <br />given similaz conditions. <br />The upgradient diversion ditches will be triangulaz ditches designed to safely divert the peak flow from the 10-year, 24- <br />how storm with a minimum of 1-foot of freeboard and located as shown on Figure 1, Bleeder Shaft Pad SAE. The <br />shaft pad will be constructed such that it slopes toward the gravel filter. The check dam and grass filter efficiency was <br />modeled using the SEDCADTM4 check dam and grass filter utility. Exhibit 5 is submitted to demonstrate that <br />application of diversion ditches, drainage collection ditches, wattles, Cwlex blankets, and the sump, rock check dam, <br />and grass filter can effectively control and treat runoff from this area. <br />Thickener Undertlow PineGnes and Borehole (TR07-60. MR07-2211-With the exceptions of the surface casing for <br />the Underflow Borehole and any intermediate access manhole(s), surface distwbance for the Thickener Underllow <br />Pipelines and Borehole will be temporary and surface activities will be limited to pipelinelborehole installation <br />activities. During construction, and for the minor surface stmctures, drainage and sediment control will be provided by <br />Alternative Sediment Controls (ABC's) consisting of combined Best Management Practice (BMP) measwes. <br />Construction-related surface disturbance will be limited to soil removal and windrowing from the pipeline trench <br />alignment and borehole pad area, and excavation of the trench and temporary stockpiling of excavated material adjacent <br />to the trench. Following installation of appropriate ABC's for each portion of the project disturbance, available soil <br />materials will be bladed from any new distwbance aeeas and temporarily windrowed on the upgradient edge of the <br />distwbance area. <br />• Much of the pipeline excavation and borehole pad distwbance will occw in aeeas that aze, or have previously been, <br />distwbed. For the remaining pipeline trench areas, consideration of soil horizon segregation must be balanced with the <br />objective of limiting overall surface distwbance. In the interest of minimizing overall surface disturbance, TCC <br />proposes to not segregate and separately stockpile individual soil horizons for the pipeline trench distwbance, and <br />submits that this approach will not significantly alter soil suitability characteristics, since the differences between the <br />soil horizons is not significant over the aeeas to be affected by trenching. For the borehole drill-pad, individual soil <br />horizons will be segregated. Generally, to avoid contamination of the windrowed soil material, excavated material will <br />be temporarily placed on the opposite side of the disturbance area. BMP's for the construction activities include: <br />• Minimize the azea of surface distwbance <br />• Completion of construction activities during the dry summer/fall period <br />• Placement of staked straw wattles downgradient of all surface distwbance areas to intercept any surface runoff <br />and trap associated suspended solids <br />• The Foidel Creek pipeline crossing (approximately 40 x 30 feet, or 0.03 acres) is located in a previously <br />distwbed portion of the channel where there is no adjacent floodplain, alluvial deposits, or wetlands. Prior to <br />distwbance of the stream channel, flows in Foidel Creek will be m;n;m;zed by closing-off the Pond A <br />discharge. Work will be scheduled during a period when significant precipitation is not anticipated (based on <br />local NWS forecasts). Just prior to initiation of work in the channel area, a staked straw-bale dam with water- <br />proof brattice-cloth covering will be placed upstream of the distwbance area, along with a portable pump and <br />pipeline, to temporarily route any significant runoff flows around the construction area. A staked straw-bale <br />dam will also be placed downstream of the distwbance area to catch any sediment resulting from the <br />construction activities. Standazd pipeline construction practices, as used for the rest of the pipeline construction <br />project, will be used in the crossing area, with additional provisions for; <br />- Placement of the pipeline at least 1.5 feet below the channel base level <br />. - Selective placement and compaction of fill material over the pipeline <br />- Placement of rock armoring within the channel over the pipeline crossing, to minimize erosion <br />potential <br />- Reconstruction of the streambanks to blend with undistwbed upstream and downstream segments <br />MR07-223 2.05-84.1 10/03/07 <br />