2018-08-31_GENERAL DOCUMENTS - M1977493

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2016 Reclamation Cost Estimate Update — Climax Mine of material. Topsoil and subsoil will come from the nearby soil stockpile located just below the Pond Shop. The dry cover will be seeded with the hydric seed mixture. The AM -06 cost for this project area did not include a general grading task for the dry tailing surface prior to cover placement. This update includes a cost for this line item. 2.11 East Side Channel The East Side Channel system diverts un -impacted stormwater run-on along the east side of the affected areas from Camp (Mine Mill Complex) to Tenmile Creek below the Mayflower Acid Building. The work involves the construction of approximately 13,100 linear feet of lined diversion channel using both a nonwoven geotextile and sized riprap. AM -06 provided a detailed estimate for this channel which has been updated in this version with 2016 unit rates from RS Means. However, the previous concept in AM - 06 for installing pipelines has been eliminated from this reclamation element as submitted in TR -21 and TR -22. 2.12 Mayflower Acid The Mayflower Acid building itself will remain so no reclamation costs have been included. 2.13 Robinson TSF Robinson TSF reclamation began in the 1980s and is ongoing. The majority of the surface has been capped with overburden rock, and covered with biosolids or suitable soil material and most of that area has been revegetated. The biosolids production area is on the Robinson TSF and will not be reclaimed until the biosolids program is no longer needed for reclamation on Climax disturbed sites. In addition there are several roads on the surface of the Robinson TSF that are still required for production and reclamation activities. These roads will remain until they are no longer considered necessary. It is currently estimated that approximately 68 acres will need biosolids or topsoil at 4 inches thick (or 36,000 cy). However, portions of that 68 acres will require additional soils cover to eliminate low spots and a thicker cover, so this cost update accounts for a total of 100,000 cy of material. 2.14 1 Dam Reclamation on 1 Dam is also close to completion. The dam face requires a minimal amount of extra biosolids application (4 inches) over a 65 -acre area (35,000 cy) to supplement existing revegetation success. 2.15 Roads Roads not to be retained for post -mining land use will be reclaimed after they are no longer needed for mining and reclamation purposes. Roads which are not permanent will be regraded as necessary to blend with the adjacent terrain and to meet natural drainage patterns. Following regrading, topsoil will be applied and seed will be spread. The seed mixture used will be appropriate to the elevation of the road. The entrances to reclaimed roads will be blocked by barriers of native rock or earthen berms to prevent vehicular access but allow wildlife access. The following roads are most likely to be reclaimed: switchbacks on Little Bartlett Mountain; access roads at the toes of 1 Dam and 4 Dam; various roads between 3 Dam and Mayflower TSF; various roads northeast and southeast of 5 Dam; and, various roads northwest of Mayflower TSF. Approximately 26,000 cy of subsoil and topsoil will be hauled to some of the road locations for reclamation purposes. The AM -06 cost for this project area included an incorrect cost basis for the cover thickness which was not consistent with the reclamation plan described in Exhibit E. This update reflects the corrected cost basis and calculation. 2.16 Robinson Lake Robinson Lake is currently used for process water storage, but it will be reclaimed after it is no longer needed for production operations and converted to a fresh water reservoir. Final reclamation will follow the methods utilized during 2008-2011 by various contractors, including removal of an estimated final 4 November 2016 (revised August 2018)