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~~r~~ ~~~~ Highs dium adsorption ratios SAR, and electrical conductivity, EC, values are ty ical of the area and as a result, more tolerant species are included in th final seed mixes. For reclamation purposes, a topsoil or suitable pla t growth medium that will be used on the top 6" of cover will be limited to maximum SAR value of 12 and EC value-of 8. For the lower 12 or 18" o cover material, depending upon the location, the maximum limits for AR and EC will be 25 and 15 respectively. As regrading of an area roceeds, soils which are projected to be placed in the top 18 or 24" of cover will be sampled for SAR and EC to determine the most suitable topsoils and subsoils. Sampling will be done on a minimum frequency of one per acre, approximately 200'centers, and 2' depth intervals. In cases where spot SAR and EC levels are high, calculated blending ratios may be used to maintain the values of the backfill material within the desired range. Roadside South Portal and Roadside Refuse Disposal Area, The final reclamation contours for the Roadside South Portal area including the Roadside Refuse Disposal Area (RSRDA) are shown of Exhibit 6C. Cross-sections representing the existing and final grade are shown on Exhibit 26. Due to a long history of mining on the site, original contours are not known. The final contours for the areas other than the RSRDA • were inferred from adjacent slopes and material balances. The final contours for the RSRDA include 2-2.5h: 1 v slopes between 10' - 15' wide benches on 30 - 40' elevation intervals, resulting in an over all slope of less than 2.5h:1v. The benches will have a grade of approximately 5% to the inside and approximately 2% north to toward a drainage channel. ~~~~ Existing cover above the first bench will be graded off of the present slope and used as cover below the first bench. Refuse material cut from the pile to establish the benches will be placed in anextension of the pile to ~~ the north and on top of the pile. This material will be spread and compacted to 90% of its maximum dry density in horizontal lifts not to ~- ~"~ exceed 2' in thickness. To establish permanent drainage control for areas ~ ~~ of above the pile, a permanent diversion will be established on the east side ~~' above the pile. This diversion will convey run-off from above the pile to~ the south and will discharge south of Sediment Pond 9 into a highway culvert. Design for the diversion is shown in Appendix 14-6. The 18" of non-toxic material required to cover the refuse pile will come from a the RSRDA borrow area located above and east of the pile shown on Exhibit 6C. Soil with high and very high EC values were eliminated for the borrow Z area quantity calculation. ~y4. °~ ~~ .t~ `~"'~~ • 14-6 (Rev. 1 /01 }