2008-09-16_PERMIT FILE - C1982056A (4)

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Trout Creek Sandstone Test Site -Drainage and sediment control for this site will include revegetating site and use of existing downslope vegetation (i.e. vegetation filter). The site is approximately 1.2 acres in size and is surrounded by existing vegetation, which will serve to limit the amount of ninon to the site. During active drilling, a berm around the site will divert upland flows around this area. Fish Creek Tipple -Drainage and sediment control at Fish Creek Tipple involves the use of diversion ditches, culverts, riprap, and Sedimentation Pond E. Details of the sedimentation control system for this site are found on pages 2.05-16 through 2.05-19 of the Fish Creek Tipple Appendix, Volume VIII. 18-Right Ventilation Shaft (TR0444) -Water & Earth Technologies, Inc. was contracted to conduct SEDCAD modeling and prepare design reports for the Bleeder Shaft Pad Small Area Exemption and access road drainage ditch and culvert design. As noted in their report (Exhibit 8T, April 2005), drainage and sediment control for the bleeder shaft pad site is provided by: • Two upgradient diversion ditches (to divert undisturbed runoff around the facility) • Two downgradient drainage ditches (to collect runoff from the disturbed area) • Gravel surfacing of the pad • The use of 20-inch diameter sediment logs (wattles) or silt fencing around the lower portion of the topsoil stockpiles • The use of Curlex single net (Curlex n erosion control blankets over seeded cut and fill slopes • The combination of a sump, rock filter (2-foot rock berm), and grass filter The combined runoff from the disturbed area will be collected in the downgradient drainage ditches and conveyed first through the sump and graded rock filter, and then through the grass filter prior to discharging through undisturbed natural vegetation between the pad and Fish Creek. As a relatively small area (approximately 4.25 acres), and given the effectiveness of the drainage and sediment control measures, the additional disturbance that would be involved in constructing a sediment pond is not warranted. Sediment contributions from the small disturbed area can effectively be controlled using the stated Best Management Practices (BMP's), and therefore falls under a n SAE, consistent with applicable provisions of Rule 4.05.2(3)(b). The will be no discharge or mixing of mine water with surface drainage from the site. Given the limited site area, agravel-surfaced pad area, the drainage and sediment control measures, and the effectiveness of the BMP's in reducing peak settleable solids concentrations to 0.23 ml/1 (modeled results), TCC submits that an SAE is justified for this site. The estimated peak flow and runoff from the site for the 10-year, 24-hour storm event is 1.52 cfs and 0.17 acre-feet, respectively. The peak settleable concentration in the runoff from the proposed Bleeder Shaft pad area is less than natural settleable solids concentrations for runoff from undisturbed lands, given similar conditions. The upgradient diversion ditches will be triangular ditches designed to safely divert the peak flow from the 10-year, 24- hour storm with a minimum of 1-foot of freeboard and located as shown on Figure 1, Bleeder Shaft Pad SAE. The shaft pad will be constructed such that it slopes toward the gravel filter. The check dam and grass filter efficiency was modeled using the SEDCADTM4 check dam and grass filter utility. Exhibit 5 is submitted to demonstrate that application of diversion ditches, drainage collection ditches, wattles, Curlex blankets, and the sump, rock check dam, and grass filter can effectively control and treat runoff from this area. 6MN Water Transfer Pipeline (MR07-224) -The 6MN Facilities project includes awater-supply transfer pipeline from the 10-Right Mine Dewatering Transfer Pipeline (includes a pipeline crossing of Fish Creek to the 6MN Million- Gallon Tank. Drainage and sediment control for the pipeline will be addressed through Alternative Sediment Controls (ASC's) and/or Best Management Practices (BMP's). As a limited and temporary disturbance, drainage and sediment control for the pipeline construction activities will be • addressed through the application of a package of site-specific BMP's. Prior to initiation of pipeline construction, and as pipeline construction advances, sediment control materials (straw wattles or silt fence) will be placed downslope of the disturbance at any location where the pipeline corridor is within 50 feet of a drainage or stream buffer zone and available soil material will be removed and windrowed adjacent to the disturbance area.. Where the pipeline disturbance is not near drainages or stream buffer zones, existing natural vegetation will provide an effective TR08-65 2.05-84 08/20/08