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Trout Creek Sandstone Test Site • The sediment control for this site will include revegetating site and use of existing down slope 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 amount of runoff onto site. During active drilling a berm around the site will keep upland from entering area. Fish Creek Tipple The sediment control at Fish Creek Tipple involves diversion ditches, culverts, riprap, and one sedimentation pond, Pond E. Details associated with the sedimentation control system is found within pages 2.05-16 through 2.05-19 of the Fish Creek Tipple Appendix, Volume VIII. NMD Power Borehole The sediment control for this site involves using gravel on the pad and the surrounding vegetation as a downslope vegetative filter. The site is approximately 1 acre and will be surrounded on three sided by topsoil stockpiles, which will limit the amount of runoff entering the pad. The SAE demonstration is presented in Exhibit 8.6. NW Mains Ventilation Shaft and Thickener Underflow Proiect (TR 01-39I Drainage and sediment control for the NW Mains ventilation shaft site is provided by an upgradient diversion ditch and access road ditch, a short containment berm at the southern limit of the pad, gravel surfacing, and the combination of a gravel filter at the low point of the berm and the natural vegetative filter existing between the shaft site and Fish Creek. As a relatively small area (approximately 1.8 acres), and given the effectiveness of the drainage and sediment control measures, the additional disturbance that would be involved in constmcting a sediment pond is not warranted and off-site sediment contributions can effectively be controlled by these measures under a Small Area Exemption, • consistent with applicable provisions of Rule 4.05.2(3)(b). There will be no discharge or mixing of mine water with surface drainage from the site. Given the lirrnted site area, a "D" soil type (Binco silty clay loam), the drainage and sediment control measures, and a distance of approximately 500' between the shaft site and Fish Creek, calculated peak flow and runoff from the site for the 10-year 24-hour storm event would be approximately 1.65 cfs and 0.13 acre-feet, respectively. Gravel and vegetative filter efficiency was modeled using the SEDCAD4 check dam and grass filter utility, the demonstration is presented in Exhibit 8S. The estimated settleable solids concentration under peak discharge conditions would be approximately 0.42 ml/l. This settleable solids level is consistent with natural sediment levels for runoff from undisturbed lands, given similaz conditions, and would be significantly reduced as the runoff passes over the vegetated area between the shaft site and Fish Creek. 18 Rieht Ventilation Shaft (TR 04-44 Water & Earth Technologies, Inc. was contracted to conduct SEDCAD modeling and prepare design reports for the Bleeder Shaft Pad Small Area Exemption (SAE) and Access Road Drainage Ditch and Culvert Design. As noted in their report (Exhibit 8T, Apri12004), drainage and sediment control for the bleeder shaft pad site is provided by: • two (2) up-gradient diversion ditches (to divert undisturbed mnoff around the facility) • two (2) down-gradient drainage ditches (to collect runoff from the disturbed area) • gravel surfacing of the pad • the use of 20-inch diameter sediment logs around the lower portion of the topsoil stockpile • the use of Curlex single net (Curlex I) erosion control blankets over seeded cut and fill slopes, and • the combination of a rock filter (2-fI rock berm) and grass filter. The combined mnoff from the disturbed area will be collected in the down-gradient drainage ditches and conveyed, first through the graded rock filter, and then through the grass filter prior to exiting through the undisturbed natural TR 04-44 2.05-84 8/18/04