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COLORADO LEGACY LAND <br /> M-1977-300 APPLICATION AMENDMENT#6,COMMENT AND RESPONSE SUMMARY TABLE <br /> COMMENT NO. COMMENT RESPONSE TO COMMENT Adw <br /> The IX resin is the only material in the WTP that requires specialty offsite disposal,Energy Fuels USA Inc.'s White Mesa Mill <br /> (6425 S.Highway 191,Blanding,Utah,84511)received the resin in November of 2018. The only fee associated with this disposal <br /> is the transportation to White Mesa Mill,Energy Fuels recovers uranium from the resin and returns regenerated resin to the site <br /> in lieu of a typical disposal fee. The most recent transportation invoice for$2,763.29 was adjusted by inflation(14%from 2018 <br /> to 2022)to$3,150.15 and included in the surety bond table shown in Exhibit L. <br /> The IX resin is only exchanged when it's fully loaded. The IX system is a secondary treatment technology and is used to polish the <br /> RO effluent only when the operator decides to add the redundancy.Even if it were to be used all the time,it would load less than <br /> 10 lbs of uranium per season,and each IX vessel is capable of loading several hundred pounds of uranium,meaning it will take <br /> many decades to require one IX change out.Thus,if a demolition were to occur only a limited amount of resin is expected to <br /> require to be shipped for disposal at White Mesa Mill. <br /> Exhibit E-Reclamation Plan(Rule 6.4.5): <br /> Based on the results of the last two in-situ treatments of the mine pool,which showed less of a reduction in CLL expects to conduct in-situ treatments no more frequently than every two years. <br /> uranium concentrations than was observed after earlier in-situ treatments,the operator suggests the mine <br /> pool chemistry may have reached a point at which continued in-situ treatments may not achieve <br /> 2 substantially reduced uranium concentrations below the current concentrations of approximately 15 to 20 <br /> mg/L.This is attributed to calcium uranium carbonate complexes that effectively limit the rate and extent <br /> of uranium reduction and removal that can be expected by stimulating microbial activity(via in-situ <br /> treatments).Accordingly,the operator is now proposing to utilize in-situ treatments only for maintaining <br /> uranium concentrations at the current levels(rather than reducing uranium concentrations).Please clarify <br /> whether in-situ treatments are still expected to be conducted approximately every two years,as previously <br /> indicated. <br /> Exhibit E-Reclamation Plan(Rule 6.4.5): <br /> The operator suggests that stability of the mine pool should be considered primarily on the effectiveness of <br /> the current pump/treat regime in keeping the mine pool below the regulatory limit(while producing water CLL will commit to installing anew groundwater well to further demonstrate the inward hydraulic gradient. The expected <br /> that meets discharge standards)and most importantly,in establishing a hydraulic gradient away from schedule for installing this well is as follows: <br /> Ralston Creek.The operator compares observed quarterly groundwater elevations in bedrock wells MW- • Fall 2022/Spring 2023: Complete alluvial valley excavation project,including Final Status Survey Report which <br /> 13,MW-15,and MW-18 to the mine pool elevation(below the regulatory limit)to demonstrate an inward documents the cleanup is complete. <br /> hydraulic gradient is maintained.Quarterly groundwater elevation data collected from these • Summer 2023: Scoping meeting to determine construction details of well (e.g.location,depth,diameter). Scoping <br /> wellsfrom2019 through 2021is presented in Table E-3.Figure E-4 provides a bedrock groundwater meeting attendees shall include CLL,DRMS,and other project stakeholders as appropriate. <br /> contour map based on water levels measured in these three wells during the Q2 2020 sampling event. • Summer 2023/Fall 2023:Well installation and development. Submittal of Technical Revision(within 30 days of <br /> completing installation of the well),including a final construction report and an updated groundwater monitoring plan <br /> 3 While the Division believes the operator has demonstrated physical stability of the mine pool by keeping it and map. <br /> below the regulatory limit of 150 feet below Steve Level(in accordance with the Modified Board Order, <br /> dated October 4,2012),the Division believes there is insufficient data available to fully demonstrate that a <br /> hydraulic gradient away from Ralston Creek is maintained.The Division recommends the operator install <br /> an additional bedrock monitoring well south of the creek,in the area between the existing alluvial <br /> monitoring wells MW-7 and MW-12 (now inoperative due to the alluvial valley excavation project),and just <br /> northwest of the"groundwater divide'illustrated on Figure E-4.The Division believes the groundwater <br /> elevations observed in a bedrock well at this location would close the gap in the current dataset and better <br /> demonstrate whether an inward hydraulic gradient is maintained at the mine.Please provide a schedule <br /> for installing the requested well and incorporating it into the quarterly sampling program.Additionally, <br /> please commit to submitting a Technical Revision within 30 days of completing installation of the well, <br /> which includes a final construction report and an updated groundwater monitoring plan and map. <br /> Exhibit E-Reclamation Plan(Rule 6.4.5): <br /> 4 <br /> PAGE 4 OF 7 <br />