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Permit Revision No. 7 -Responses March 7, 1997 Page 11 61. Typical road sections and the location where they will used is included on the revised construction drawings. MCC has utilized Mechanically Stabilized Earth embankments (MSE walls) on slopes steeper than 2H:1 V. Cross-sections of the MSE walls are also included in the construction drawings. 62. As above, total net fill volume required for the SGFA has been recalculated based on final design drawings and now totals 159,800 CY (112,800 CY common fill, 25,300 CY subbase, 15,700 CY base coarse, 2,000 CY of riprap). Of this volume, approximately 148,000 CY will come from the usable materials underlying the RPE site (TR#79). Approximately 5,000 CY of road base material, 2,000 CY of riprap, and 5,000 CY of select structural fill will be purchased and imported from offsite sources. See Table 1 in Exhibit 69. All of the 159,800 CY of fill material will remain within the site as the SGFA is regraded to approximate original contour (AOC) during reclamation, although relocation of approximately 80,00 CY of material will be required. For example, approximately 20,000 CY of common fill material from the shaft site area will be used to reclaim light-use roads prior to topsoiling. An additional 20,000 CY of common fill material from the shaft sites will be relocated to the substation azea during regrading and slope flattening of this site. The remaining 40,000 CY of relocated material will be taken from the two stream crossing embankments (Sylvester Gulch crossing and the "Substation Gulch" crossing) and used to reclaim the main access road back to a light-use road. The remaining approximately 80,000 CY of net fill material, which includes the material used to construct engineered embankments along the lower portion of the main hauUaccess road and the remaining fill material at the shaft sites, will generally remain in place and be regraded to AOC. Leaving the geogrid type engineered embankments in place will create significantly less disturbance during reclamation and will also provide additional long term stability to reclaimed slopes. 63. Only a portion of the fill material used to construct the Sylvester Gulch main hauVaccess road and substation access road is planned to be removed because the reclamation plan for these two roads includes reducing the road to a light-use road. As stated in the responses to question 62, the geogrid type engineered embankments will be left in place. Also, please note the light-use road to remain after reclamation, will follow the new alignment and not the alignment that exists currently. 64. The vertical alignment of all roads to be constructed is shown on the Seal design drawings, which aze enclosed for Exhibit 69. 65. The wetland mitigation site is not within MCC's permit area and is not planned to be included in the permit area. Therefore, the mitigation site will not be described in the permit. As with the mitigation site for the Refuse Pile Expansion (RPE, TR#79), MCC will forward the approval letter from the U.S. Army Corps of Engineers (USAGE) once it is received. MCC will not disturb the wetland areas in Sylvester Gulch until approval from the USAGE is granted. The location of the wetlands to be affected are shown on the enclosed drawings (Figures 2-10).