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2019 Reclamation Cost Estimate Update—Henderson Mine& Mill
<br /> Transportation Building, Mill Building, Ore Storage and Conveyor Terminus, Concentrate Thickener,
<br /> Mobile Equipment Shop, Nokes Storage Building, Acid House, Hazardous Waste/Flammables Building,
<br /> Bulk Storage Warehouse, Truck Scale Building, Electric Switchgear Building, Sewage Treatment
<br /> Building, Process and Potable Water Tanks, Topsoil Shop, Tailing Operations/Maintenance Shop, Ute
<br /> Park Pump Station, East Branch Pump Station, West Portal Building, Rectifier Station 5, Power Line
<br /> Spurs and Lighting, Williams Fork and South Williams Fork bridges, Tailing Distribution System including
<br /> Drop Towers, and the Overland Conveyor Superstructure. Additionally, there will be a significant amount
<br /> of asphalt to be demolished across roadways and parking areas. To the extent possible, the salvageable
<br /> and recyclable materials obtained from these structures and facilities will be retrieved and sold, or
<br /> recycled, and so a corresponding direct cost credit will apply against the site's closure cost (but not
<br /> 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 Mill Yard and Access Road task described above in Section 2.6,
<br /> amongst others.
<br /> 2.12 Williams Fork Pump System
<br /> The Williams Fork Pump System will remain post closure for continuation of water management.
<br /> However, a limited amount of basic reclamation will be required at closure of the Mill site to include
<br /> approximately 5,000 cy of regrading and up to 8 acres of revegetation.
<br /> 2.13 Tailings Line and Power Line
<br /> Several linear facilities at Henderson will not be needed following cessation of production operations.
<br /> These include the tailings pipeline and power line alignments. Following facility demolition (covered under
<br /> the Mill Site Demo task), disturbed footprints will be regraded and revegetated. Up to 56,000 cy of
<br /> regrading is anticipated for these alignments and 50 acres of reclaimed area will be drill seeded, planted
<br /> with trees and shrubs and/or applied with maintenance fertilizer.
<br /> 2.14 Tailing Facility Structures
<br /> Reclamation at the Tailing Operations/Maintenance Shop, Topsoil Shop, Pump Station, etc. will involve
<br /> regrading and revegetation. Up to 52,000 cy of regrading is anticipated and 14 acres of regraded area will
<br /> be drill seeded, planted with trees and shrubs and/or applied with maintenance fertilizer. Demolition of
<br /> these facilities is included in Mill Site Demo.
<br /> 2.15 Mill Water Return Pipeline
<br /> The Mill Water Return Pipeline and Access Road alignments will be reclaimed involving the regrading of
<br /> approximately 18,000 cy and 32,000 cy of material, respectively, followed with revegetation by the drill
<br /> seed method and the planting of trees and shrubs on up to approximately 31 acres.
<br /> 2.16 Topsoil Stockpiles and Haul Roads
<br /> Again, haul roads not to be retained for post-mining land use will be reclaimed after they are no longer
<br /> needed for reclamation purposes. As such, and following depletion of the topsoil stockpiles, the haul
<br /> roads and stockpile footprints will be reclaimed. Reclamation will involve regrading of up to approximately
<br /> 160,000 cy followed with revegetation by the drill seed method and the planting of trees and shrubs on up
<br /> to approximately 50 acres of total reclaimed surface.
<br /> 2.17 PC3 Overland Surface Conveyor
<br /> In line with the Conveyor Access Road task and following demolition of the conveyor and associated
<br /> infrastructure (covered under the Mill Site Demo task), the PC3 overland surface conveyor corridor will be
<br /> 4 Dec 2019
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