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2019 Reclamation Cost Estimate Update—Henderson Mine& Mill <br /> 2 Site Specific Reclamation Planning <br /> As specified in previous permit submittals, specific reclamation strategies have been outlined for all areas <br /> of the Mine and Mill. The following narrative is provided to give a basis for the reclamation cost estimate, <br /> and is not intended to modify the reclamation requirements approved in the reclamation permit, as <br /> amended and revised. This narrative describes reclamation approaches for all areas including the Tailing <br /> Deposition Area (TDA), access roads and reservoirs, utilities and utility corridors, yards and storage <br /> areas, surface and underground pumping systems, shafts, and bulkhead construction. It also refers to the <br /> long-term strategy for site-wide water management and treatment, and for the demolition or repurposing <br /> of structures upon cessation of mining. Note that #2 shaft at the mine will be kept for access and intake <br /> air; #5 shaft for exhaust. The attached Figures 1 through 4 have been utilized as the basis for the <br /> proposed final reclamation design and illustrate the final facility layout with respect to post-mine land use. <br /> 2.1 Vent Shaft <br /> Sealing and demolition of the Vent Shaft (aka #4 Shaft) to prevent long-term access is covered under <br /> Mine Site General Reclamation task. The Vent Shaft surface area will be revegetated by the broadcast <br /> seed method (approximately 1 acre). <br /> 2.2 Mine Site Demolition <br /> Several structures at the Mine site not being repurposed post mining will no longer be required during the <br /> post-reclamation period and will be demolished. These structures include the Compressor Building, Plant <br /> Services Building, #1 Shaft, #1 Shaft Hoist House, #3 Shaft, #3 Shaft Heater Building, Aggregate <br /> Stacking Building and the building adjacent to it, Batch Plant, Bulk Oil Storage Building and the building <br /> adjacent to the Used Oil Tank, the Fan Control/Switchgear Building, and the Natural Gas Building. <br /> Additionally, there will be a significant amount of asphalt to be demolished across roadways and parking <br /> areas. To the extent possible, the salvageable and recyclable materials obtained from these structures <br /> and facilities will be retrieved and sold, or recycled, and so a corresponding direct cost credit will apply <br /> against the site's closure cost(but not included in this estimate). <br /> Material that is not retrievable or practicably recycled will be disposed of by burial. Buried pipe, wire, etc. <br /> will be left in place during reclamation if it does not interfere with regrading activities and is non-toxic or <br /> not hazardous. Foundations deeper than 3 feet from the reclaimed surface that will not interfere with <br /> regrading activities will also be left in place. Concrete floors, walls, equipment pedestals, and foundations <br /> which are at or near grade will be pulverized in place and buried as part of the mass regrade and <br /> revegetation which is included under the Mine Site General Reclamation task described below in Section <br /> 2.3. <br /> 2.3 Mine Site General Reclamation <br /> The surface area at the Mine site will be regraded and reclaimed, including 3 ponds (Ponds 1, 1.1, 1.2), <br /> the roads and parking areas, and culverts and drainage channels. Additionally, 3 shafts (Shafts 1, 3, 4) <br /> will be permanently sealed with structural plugs. The total area of disturbance to be reclaimed will be <br /> approximately 100 acres. Total earthmoving associated with the Mine site reclamation will exceed <br /> 500,000 cy. Seeding and signage will complete the reclamation activity. <br /> 2.4 Portal Area <br /> The portal area will be reclaimed in accordance with a standard regrading and revegetation approach. <br /> Regrading of the portal will incorporate both ripping (approximately 100,000 cy) to allow for long-term, <br /> stable slopes and regrading of the general area (approximately 33,000 cy). This will be followed with <br /> revegetation by drill seeding and the planting of trees and shrubs over 25 acres. <br /> 2.5 Conveyor Access Road <br /> Roads not to be retained for post-mining land use will be reclaimed after they are no longer needed for <br /> mining and reclamation purposes. As such, and following demolition of the conveyor and associated <br /> infrastructure (covered under the Mill Site Demo task), the Conveyor Access Road will be regraded <br /> (approximately 116,000 cy) to blend with the adjacent terrain and to meet natural drainage patterns. <br /> 2 Dec 2019 <br />