Common use of Proposed Action Description Clause in Contracts

Proposed Action Description. The EE/CA identified, evaluated, and screened potentially applicable technologies for reducing identified human health and ecological risks posed by the mine-affected areas of the Site. The applicable technologies were then assembled into candidate removal action alternatives. Five removal action alternatives for mine rock areas and four removal actions for mine portals were evaluated. These alternatives represent well established and proven technologies that have been implemented at similar uranium mine sites to address similar conditions. The removal action alternatives for mine rock include: • Alternative M-1 – No Action • Alternative M-2 – In-Place Stabilization with Stormwater and Institutional Controls • Alternative M-3 – In-Place Covering of Mine Rock Piles • Alternative M-4 – Excavation, Consolidation and Cover at Mine Affected Areas • Alternative M-5 – Excavation, Consolidation and Cover at Open Pit Repository The removal action alternatives for mine portals include: • Alternative P-1 – No Action • Alternative P-2 – Close Upper Mine Openings with 300-Foot Level Portal Gate • Alternative P-3 – Close Upper Mine Openings with 300-Foot Level Portal Rock Backfill Closure • Alternative P-4 – Close Upper Mine Openings and 300-Foot Level Portal Concrete Bulkhead Based on the detailed and comparative analysis of the removal action alternatives, the combination of Mine Rock Alternative M-5 and Portal Alternative P-4 best satisfies the evaluation criteria. Both the mine rock and the mine portal alternatives are protective of human health and the environment in reducing or eliminating the exposure pathways and risks. Both alternatives are effective in reducing incremental radiation risks due to external gamma radiation and inhalation of radon decay products associated with mine rock and the inhalation of radon decay products associated with the mine openings. The alternatives also comply with State and Federal Applicable or Relevant and Appropriate Requirements (ARARs). However, the alternatives will not eliminate the Site-wide risk to human health, as radiation risks from background gamma radiation and radon in the naturally mineralized area exceed the acceptable human health risk and dose criteria. • Removal of ore rock within the intertidal zone associated with former loading ramps and ore loading operations and consolidation at the Open Pit Repository. • Removal of the miscellaneous solid waste and debris and transport for off-site recycling and disposal, except for drill core that would be consolidated at the Open Pit Repository; • Excavating, transporting and consolidating the mine-affected material from the OSA, and the mine rock piles from the 300-Foot Level; 700-Foot Level, and 900-Foot Level (North and South) at the Open Pit Repository; • Excavating and consolidating the I&L Spur road materials in the Open Pit and closing the road; • Removing and consolidating the identified mine road (between the 700-Foot and 900-Foot Levels) surface and embankment material in the Open Pit and closing the mine road; • Excavating the mine rock from the identified segments of the haul road and consolidating the material in the Open Pit; • Placing a synthetic geomembrane barrier and 2-foot thick earthen cover on the minerock materials consolidated at the Open Pit Repository from the on-site borrow source and constructing stormwater controls to protect the covered areas; and • Implementing institutional controls, access controls, and/or land use restrictions to protect the integrity of the removal action. The primary factors that resulted in selection of Mine Rock Alternative M-5 as the recommended Removal Action included: • Will be effective in achieving the RAOs for the removal action areas, including reducing the predicted mine rock incremental dose to less than 15 mrem/year and the lifetime risk to less than 1E-5 above background for occupational workers and recreational users of the Site; • Will provide permanent containment of the mine-affected materials by consolidating mine rock and mine-affected materials in the Open Pit Repository, reducing the overall mine rock footprint and requiring less cover material; • Will remove the OSA materials near the shoreline of the West Arm of ▇▇▇▇▇▇▇▇ Bay, significantly reducing human health exposures to gamma radiation and radon for Site visitors and occupational workers; • Will remove the 300-Foot Level mine rock pile located in the relatively steep areaadjacent to ▇▇▇▇▇▇▇▇ Creek, eliminating potential concerns with the long-term geotechnical and erosional stability and permanence of the 300-Foot Level mine rock pile; • Will return all mine rock and mine-affected materials to the Open Pit Repository where the characteristics of the materials are consistent with the naturally mineralized area and where the flatter topography is more suitable for long-term mine rock containment and cover stability; • Will reduce the gamma and radon emanation at the cover surface of the Open Pit Repository by placing the lower gamma activity material from the 300-Foot Level mine rock pile over the higher gamma activity mine rock; • Will require closure of the I&L Spur road, the haul road to the 300-Foot Level, and the mine road from the 700-Foot Level to the 900-Foot Level, reducing human access to the 300-Foot and 700-Foot Levels; • Will require that institutional and access controls and/or land use restrictions beimplemented at only one isolated location, where access to the 900- Foot Level is already limited compared to other areas of the Site; • Will consolidate mine rock and place a cover on the Open Pit, reducing the inflow of water into the underground mine via the 900-Foot Level portal; thereby reducing drainage fromthe 300-Foot Level portal; • Closure of the upper mine openings consisting of the 900-Foot Level portal, air vent shaft and 700-Foot Level portal; • Constructing a concrete bulkhead at the 300-Foot Level portal, with a water collection and piping system to convey the drainage from the portal directly to ▇▇▇▇▇▇▇▇ Creek; • Implementing institutional controls, access controls, and/or land use restrictions to protect the integrity of the portal closures. The primary factors that resulted in selection of Portal Alternative P-4 as the recommended removal action included: • Will significantly reduce radon exhalation from the mine openings, significantly reducing the human health exposure pathway and risk due to inhalation of radon decay products from the mine openings; • Has the least uncertainty of alternatives in achieving the RAOs for protection of human health and the environment by significantly reducing radon exhalation from the mine openings; • Will reduce human and ecological pathways associated with direct contact with thedrainage water by collecting and piping the 300-Foot Level portal drainage to ▇▇▇▇▇▇▇▇ Creek; • Will eliminate the potential for water drainage from the 700-Foot Level portal.