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• 4.2.4 Roads <br />4.2.4.1 Access Roads <br />The access/temporary haul road has been redesigned to accommodate the new surface <br />facilities location. The road alignment and the haul portions are identified in Figure 4.2- <br />3, and a profile is shown in Figure 4.2-4. Professional Engineer's certification for the <br />stability of the haul road below Sediment Pond A and a discussion of the road fill and <br />cuts are provided in Exhibit 4.2-2. <br />The access/temporary haul road is now 3,100 feet long and 30 feet wide. Average <br />grade is now 4.1 percent (compared to 4.6 percent previously); maximum grade is still 8 <br />percent. The roads are surfaced with anon-acid ,non-toxic-forming gravel, and crowed <br />to prevent ponding. <br />Culverts are installed under the roads to provide cross drainage of the 10-year, 24 hour <br />peak flows in the ephemeral water ways tributary to the Colorado River (Refer to <br />Section 4.3.4.2 for further discussion of culverts). The culverts are corrugated metal <br />• pipe CMP and are sized assuming headwater to depth rations of 1.0. Location of the <br />culverts are shown of Figure 4.2-3. Culvert sizes and pertinent information are listed in <br />the table. <br />Table 4.2-3 Culvert S ecifications -Surface Facilities Area <br />Culvert 10-Yr. 24-hr Flow Cfs Diameter -inches Max Ca cls FI/D=1 <br />Ct 12 Existin <br />C2 9 24 11 <br />C3 18 30 20 <br />C4 9 24 11 <br />CS 39 42 45 <br />C6 2 15 4 <br />C7 1 24 11 <br />CMP culverts are of sufficient gauge to meet the requirements of Rule 4.03.1(4)(e)(ii) <br />and were covered by compacted fill to a minimum depth of 1-foot. The culverts were <br />designed and installed to avoid plugging, collapse and erosion at the inlets and outlets. <br />• <br />NC{G -Coal Ridge No. 1 4-10 5/00 <br />