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Mountain Coal Company Exhibit 69 West Elk Mine Sylvester Gulch Facilities -- • Each of the shag benches will be graded away from the shafts at 5% such that local bench drainage will be routed to a main sediment control ditch, which will be located along the southern edge of the site. The sediment control ditch will be a trapezoidal channel two feet wide with side slopes of 2.5:1 and will be concrete lined or shotcreted for ease of cleaning and maintenance. At the western edge of the construction laydown bench, the sediment control ditch will enter a 30" buried culvert which routes the sediment ditch flow to the sediment control pond inlet channel. Concrete baffled apron drops aze also incorporated into the sediment ditch at the two locations where the sediment ditch transitions between benches. These baffled apron drops aze self-cleaning and eliminate the need for overly steep grades. The sediment ditch and culvert aze designed to safely carry the peak flow from the 25 year, 24 hour storm event over the shafts site. A sediment control pond will be built at the lower west end of the shafts site to capture sediment laden runoff from the shafts site area. The pond will be sized to at least contain the 10 year, 24 hour runoff volume of 56,600 cubic feet (130 acre- feet) from the site, and will be oversized by 30% (039 acre-feet) to provide additional storage for snowmelt and sediment. The pond will be lined with 60 mil HDPE and will be surfaced with ] 8 inches of pea gravel to facilitate periodic sediment removal. • All ditch, culvert and pond designs aze in Exhibit 66. I~ Ventilation Shaft #3, Degasification Hole and Electric Borehole Facilities Due to the time that will be required to complete the construction of ventilation Shafts #1 and #2, it is necessary for MCC to construct a third, smaller diameter ventilation shaft (#3) to more immediately supply air to the mine. MCC anticipates beginning the construction of Shag #3 by mid-July and have it on-line by early December. Shaft #3 is located approximately 1.5 miles southeast of the existing Sylvester Gulch ventilation fan and approximately 400 feet east of the electric borehole site. A degasification hole will be located approximately 200 feet west of the electric borehole site. The purpose of the degasification hole is to vent mine gases to the outside atmosphere. A vacuum pump placed next to the hole pumps gases out of the mine and through surface piping to move the gas up and away from the site. Dimensions of these structures are provided in Table 3 - "Shaft #3, Degas Hole and Electric Borehole Quantities." Site development for the shaft site includes construction of approximately 900 feet of new 14-foot wide light-use road (distance measured from the location where the Shaft #3 road leaves the electric borehole road), and a 65-foot wide by 145-foot long drill pad. The shaft will be a 10-foot finished diameter ventilation shaft, and will be approximately 580 4 Nav- 1996 PR07R; Revised May /997MR1/6; ReviredJuL /997MR2L9