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Mountain Coal Company Exhibit 69 <br />West Elk Mine Sylvester Gulch Facilities <br />system is approximately 2360 feet. All Clearwater ditches and culverts will be sized <br />to carry the peak flow from a 100-year, 24-hour event. <br />Each of the shaft benches will be graded away from the shafts at 5% such that local <br />bench drainage will be routed to a main sediment control ditch, which will be <br />located along the southern edge of the site. The sediment control ditch will be a <br />trapezoidal channel two feet wide with side slopes of 2.5:1 and will be concrete <br />lined or shotcreted for ease of cleaning and maintenance. At the western edge of the <br />construction laydown bench, the sediment control ditch will enter a 30" buried <br />culvert which routes the sediment ditch flow to the sediment control pond inlet <br />channel. Concrete baffled apron drops are also incorporated into the sediment ditch <br />at the two locations where the sediment ditch transitions between benches. These <br />baffled apron drops are self-cleaning and eliminate the need for overly steep grades. <br />The sediment ditch and culvert are designed to safely carry the peak flow from the <br />25 year, 24 hour storm event over the shafts site. <br />A sediment control pond will be built at the lower west end of the shafts site to <br />capture sediment laden runoff from the shafts site area. The pond will be sized to at <br />least contain the 10 year, 24 hour runoff volume of 56,600 cubic feet (1.30 acre- <br />feet) from the site, and will be oversized by 30% (0.39 acre-feet) to provide <br />additional storage for snowmelt and sediment, The pond will be lined with 60 mil <br />HDAE and will be surfaced with 18 inches of pea gravel to facilitate periodic <br />sediment removal. <br />All ditch, culvert and pond designs are in Exhibit 66. <br />Ventilation Shaft #3, DegasiScation Hole and Electric Borehole Facilities <br />Due to the time that will be required to complete the construction of ventilation Shafts #I <br />and #2, it is necessary for MCC to construct a third, smaller diameter ventilation shaft <br />(#3) to more immediately supply air to the mine. MCC anticipates beginning the <br />construction of Shaft #3 by mid-July and have it on-line by early December. Shaft #3 is <br />located approximately ].5 miles southeast of the existing Sylvester Gulch ventilation fan <br />and approximately 400 feet east of the electric borehole site. <br />A degasification hole will be located approximately 200 feet west of the electric borehole <br />site. The purpose of the degasification hole is to vent mine gases to the outside <br />atmosphere. A vacuum pump placed next to the hole pumps gases out of the mine and <br />through surface piping to move the gas up and away from the site. Dimensions of these <br />structures are provided in Table 3 - "Shaft #3, Degas Hole and Electric Borehole <br />Quantities." <br />Site development for the shafr site includes construction of approximately 900 feet of <br />new 14-foot wide light-use road (distance measured from the location where the Shaft #3 <br />4 Nuv. 1995 PR07R; Revised Mav 1997 MR21 fi <br />Revised Jul. /997 MR219r Revised Juue 2003 MR297 <br />