80 22 004 2024 PRA Overview Annu : simplebooklet.com

KEY TERMSAdministrative Settlement Agreement/Order on Consent: A negotiated agreement between the party and a regulatory agency to address potential cleanup sites.Removal Action: A response to actual or threatened releases of a pollutant or contaminant that pose a threat to public health or the environment.Overburden: A mining term for waste rock or soil overlying a mineral deposit.Remedial Investigation/Feasibility Study: The Remedial Investigation (RI) is the mechanism for collecting data to characterize site conditions, determine the nature and extent of the waste and contamination, assess risk to human health and the environment, and conduct treatability testing, if needed. The Feasibility Study (FS) is the mechanism used for the development, screening, and detailed evaluation of alternative remedial actions.Proposed Plan: A brief summary of the alternatives studied to conduct the cleanup response for a site. The Proposed Plan, as well as the RI and FS, form the basis for the lead agency’s preferred alternative. It is made available for public comment.Record of Decision: The decision document issued by the lead regulatory agency following the Proposed Plan that documents the remedial action for a site. ACRONYM LISTBLM – Bureau of Land Management CERCLA – Comprehensive Environmental Response, Compensation, and Liability Act CVF – Cross Valley FillDEQ – Idaho Department of Environmental Quality EIS - Environmental Impact StatementEPA – Environmental Protection Agency FS – Feasibility StudyFWS – U.S. Fish and Wildlife Service MRP – Mine Reclamation Plan O&M – Operations and Maintenance P4 – P4 Production, LLCPDI – Predesign InvestigationPRB – Permeable Reactive Barrier RA – Remedial ActionRD – Remedial DesignRDWP – Remedial Design Work PlanRI – Remedial Investigation ROD – Record of DecisionSOU – Sub-Operable UnitUSFS – United States Forest Service XRF – X-Ray FluorescenceP4 South Rasmussen Mine

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ARE YOU TIED TO PHOSPHATE?If you are reading this, chances are you live and work in southeastern Idaho. If you live in this part of the state, your life is likely somehow tied to phosphate. Phosphate mining and manufacturing is a major industry in southeast Idaho. Many people don’t realize that the area east of Soda Springs, Idaho is one of the country’s major phosphate producing regions. In 2023, phosphate mining and manufacturing* directly contributed an estimated 1,765 industry jobs, $201.1 million in payroll and benets, average salary and benets of $112,966 per job, and $715 million to the gross state product (Source Lightcast 2024 Q1 Data Year 2023 -Except for GSP). Mining royalties and taxes continue to provide millions in revenue to the State of Idaho, which funds education and other local programs.Approximately 250 million years ago, this area was a shallow sea where the sudden death of tiny organisms created the presence of the phosphate ore that is mined today. Severe folding and thrusting of the rock layers exposed outcrops of the Phosphoria Formation along area ridges and valleys, which have been mined mainly by open pit mining techniques for the past 80-plus years.Phosphate mining can cause some adverse ecological consequences. For example, waste rock dumps and open pits can act as pathways that transport selenium and other contaminants to the environment through ground and surface water.The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as well as state law, provide a framework to address these issues, which occur at various phosphate mines in the region. Investigations and planning for cleanup at mining sites are ongoing with oversight from the U.S. Environmental Protection Agency (EPA), United States Forest Service (USFS), Idaho Department of Environmental Quality (DEQ), Bureau of Land Management (BLM), Shoshone Bannock Tribes, and U.S. Fish and Wildlife Service (FWS).The agencies, Tribes, and mining companies participating in this process welcome public involvement because it produces better cleanup decisions. The agencies provide updates regarding the progress at each of the mine sites at a booth during the Caribou County Fair and through this fact sheet, which contains contact information for additional information.*Total nonmetallic mining and manufacturing. 2023 Idaho Mining Association direct estimated employment and gross state product.Public Outreach at the Caribou County Fair

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CERCLA REMEDIAL ACTION SITES These sites are led by federal agencies, such as EPA and USFS, or with state co-leads where cleanup is governed by the method established by CERLCA to characterize the nature and extent of contamination and assess risks to evaluate potential remedial options. Ballard, Henry, and Enoch Valley MinesActive Status:Ballard Mine –Remedial Design (RD); Remedial Action (RA)Henry Mine – FSEnoch Valley Mine – RIThe EPA issued a Record of Decision (ROD) for P4 Production, LLC’s (P4’s) Ballard Mine on October 1, 2019; thus, completing the RI/FS process. As identied in the ROD, a nal cleanup plan was selected for this historic mine site that includes partial backlling and grading of mine pits and mine dumps, constructing a cover system, and treating contaminated groundwater. The ROD also accommodates recovery of phosphate ore from the site during implementation of the remedy. P4 obtained the phosphate lease from the BLM in November 2020 to re-mine material that contains valuable minerals. Re-mining of ore is under the jurisdiction of the BLM and is not considered part of the CERCLA response action. The EPA worked with the BLM to ensure that the design for the CERCLA remedy is consistent with the BLM-approved Mine Reclamation Plan (MRP). On May 21, 2021, the Consent Decree for the RD/RA was signed by P4 and the EPA. This legal agreement details the work to be performed by P4 during the RD/RA. The Shoshone Bannock Tribes, DEQ, and FWS have a legal obligation to the project because of either land administration/hunting and shing rights or because they are landowners. The EPA also works with the BLM and Idaho Department of Lands on the re-mining aspect of the project. In August 2021, the EPA, in coordination with the BLM and Idaho Department of Lands, approved a Remedial Design Work Plan (RDWP) that details the approach for designing the remedy to ensure the design addresses ROD requirements. The RDWP includes a schedule for the remedial cleanup. The 30% design was submitted to the EPA, Shoshone Bannock Tribes, DEQ, and FWS; all agencies provided review comments to P4 on this document. P4 responded to these comments and is developing a schedule for submitting a 60% design. In late 2021, P4 installed a Permeable Reactive Barrier (PRB) to study the feasibility of using this technology at the site. P4 monitored the performance of the PRB for the past year and will submit a report detailing the monthly monitoring of the PRB. P4 was approved to begin some of the early work to support the RD/RA in July 2021. Some of the early work completed in 2021 included construction of the contractor ready line/laydown area, development of topsoil stockpile areas, and several haul and access roads. Under an approved 2021 Predesign Investigation (PDI) Work Plan, additional characterization work was completed at Ballard Mine in January 2022.Seventeen monitoring wells and nine soil borings were drilled and sampled. This information will be used to better understand borrow material properties and groundwater conditions at the site. The remaining eld activities outlined in the 2021 PDI Work Plan occurred in the Spring of 2022, including additional characterization of proposed PRB locations, groundwater sampling, and aquifer testing for several of the PDI characterization wells. A Draft PDI Report will be prepared to summarize the 2021 and 2022 PDI geophysical surveys, borrow source investigations, and PRB characterization.In October 2021, P4 installed a pilot study PRB (PRB4) along the east side of Ballard Mine. PRBs have been successfully used as an in-situ remedial component at other phosphorus mine sites to treat shallow groundwater. The PRB includes an excavated trench lled with a mixture of permeable sand and organic matter (e.g., alfalfa and wood chips) that provide a food source for natural microbes in the soil. As the groundwater passes

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Next Steps for Henry MineFeasibility StudyProposed PlanPublic Comment PeriodRecord of DecisionRemedial DesignNext Steps for Enoch Valley MineRemedial InvestigationFeasibility StudyProposed PlanPublic Comment PeriodRecord of DecisionNext Steps for Ballard MineFeasibility StudyProposed PlanPublic Comment PeriodRecord of DecisionRemedial DesignNext Steps for Champ MineRemedial InvestigationFeasibility StudyProposed PlanPublic Comment PeriodRecord of Decisionthrough the PRB, biochemical reactions cause the water chemistry to change, which in turn helps in removing the selenium. Under the approved PRB Treatability Study Work Plan, drilling and installation of eight performance monitoring wells (PRB4-4 thru PRB4-11) in the vicinity of PRB4 followed construction in December 2021. The data collected from the treatability study will be used to design additional PRBs that are a component of the CERCLA remedy. The draft eld report summarizing this effort was submitted to the EPA in mid-March 2023. In addition to this work, groundwater and surface water data have been collected monthly starting in May 2022. P4 submitted a 60% Remedial Design Plan for the east side of the site (Phase 1) on November 30, 2023. Included in the 60% design submittal was an update to the Phase 1 Remedial Design schedule to reect the November 30, 2023 submittal date. On December 31, 2023, P4 submitted the Ballard Mine PRB Treatability Study for PRB4. Both the 60% Remedial Design (Phase 1) and the PRB4 Treatability Study were shared with the agencies and Tribe for their review and comments. Findings of the PRB4 Treatability Study will be used to inform the design of the remaining proposed site PRBs. P4 is currently working on the FS at Henry Mine and a draft FS is anticipated in 2025. An RI is anticipated to begin at Enoch Valley Mine in 2024.Champ Mine Active Status: RIField work conducted by Nu-West to support the RI continued, including groundwater and surface water sampling. The Baseline Human Health Risk Assessment was completed in 2022. The RI Report is under review by the agencies.

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Georgetown Canyon MineActive Status: Ecological and Human Health Risk AssessmentsBaseline Human Health and Ecological Risk Assessment work plans are being developed and will be approved in 2024. Draft Risk Assessments will be submitted in 2024. Surface water and groundwater sampling continues to be conducted annually during high-ow (May) and low-ow (September) periods.Georgetown Canyon Mine supplied a fertilizer plant located along Georgetown Creek. Ore was transported from mine pits down Phosphoria Gulch to the plant on a belt conveyor. The area where the plant sat is still visible today. Reclamation activities at the former industrial site were completed in 2016.Next Steps for Georgetown Canyon MineBaseline Risk AssessmentsFeasibility StudyProposed PlanPublic Comment PeriodRecord of Decisionyou know?Enoch Valley Mine

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Mountain Fuel MineActive Status: Ecological and Human Health Risk AssessmentsNu-West continued groundwater and surface water sampling work to support the RI. The Baseline Human Health Risk Assessment and Ecological Risk Assessment were approved in 2022. The RI Report is currently under review by the agencies.Next Steps for Mountain Fuel MineRemedial InvestigationFeasibility StudyProposed PlanPublic Comment PeriodRecord of DecisionConda/Woodall Mountain MineActive Status: FS; Operations and Maintenance (O&M) The RI report was submitted in May of this year and is under review by the agencies.Next Steps for Conda/Woodall Mountain MineFeasibility StudyProposed PlanPublic Comment PeriodRecord of DecisionRemedial DesignMining at the Conda Woodall site spanned many decades, more than any other mining site in the Phosphate Resource Area. you know?

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North Maybe Mine Active Status: RI, Proposed Plan, Public Comment PeriodIn 2023, Nu-West conducted eld activities associated with the North Maybe Mine RI/FS, including surface water and groundwater monitoring. The Baseline Human Health Risk Assessment for the Open Pit Sub-Operable Unit (SOU) was approved in 2022 and the RI was approved in early 2023. Agencies continued negotiation of a Consent Decree to implement the East Mill Dump SOU Interim ROD in 2023. A public comment period on the No Action Proposed Plan for the Open Pit SOU was conducted in mid 2023. Agencies continued reviewing the FS for the West Ridge Operable Unit in 2023.Next Steps for North Maybe MineRemedial InvestigationFeasibility StudyProposed PlanPublic Comment PeriodRecord of Decision North Dry Valley Mine Active Status: Administrative Settlement Agreement/Order on Consent The DEQ, BLM, and the Tribes are close to completing a proposed settlement agreement and statement of work for conducting an RI/FS for the site. The next step is for this agreement to go to the FMC Corporation for review.The North Dry Valley Mine is mostly located on private land owned or leased by the FMC Corporation.Next Steps for North Dry Valley MineSite InvestigationRemedial InvestigationFeasibility StudyProposed PlanPublic Comment Periodyou know?Mountain Fuel Mine

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Smoky Canyon Mine Active Status: Selection of Remedy, ROD, Remedial DesignIn 2023, the Simplot Smoky Canyon Mine continued optimized operation of its Pilot Surface Water Treatment Plant, which uses advanced technologies (including ultra ltration, reverse osmosis, and uidized bed reactors) to treat mining-impacted spring or stream water. Water is pumped through the system at approximately 1,800 gallons per minute. Iron co-precipitation is added to the treatment process to further enhance the removal of selenium from the impacted water. The FS, which discusses potential remedial options, was nalized in early 2023. The Proposed Plan was published in April 2023 with a 30-day public comment period from April 24 to May 24. A 30-day extension of this comment period was requested and granted, concluding on June 26. The comments were addressed and will be released as part of the Record of Decision. The recommended combined remedy includes three elements: (1) treatment of surface water (Alternative 2b – Water Treatment at the Hoopes Water Treatment Plant), (2) treatment of alluvial groundwater (Alternative 2c – PRB Downgradient of Pole Canyon, and (3) source control for Wells Formation groundwater and surface water (Alternative 3c – Enhanced Dinwoody Covers at Target Areas). It is anticipated that the Record of Decision should be issued in 2024 with the remedial design to follow.While Smoky Canyon Mine is physically located in Idaho, the majority of the employees live in the Star Valley, Wyoming area, sharing the economic inuence to both states.Next Steps for Smoky Canyon MineFeasibilty StudyProposed PlanPublic Comment PeriodSelection of RemedyRecord of Decisionyou know? South Maybe Canyon Mine Active Status: RI, Proposed Plan, Public Comment Period, O&M, 5-Year ReviewNu-West performed eld activities at the site and continued O&M activities on the Cross Valley Fill (CVF). Agencies completed a 5-year review of the removal action at the CVF in early 2023. Surface water concentrations of selenium measured near the containment area have declined by greater than 95% since cleanup work began. RI eld work continued in Maybe Creek in 2023 (including soil, surface water, groundwater, surveys, and sediment sampling). The Baseline Human Health Risk Assessment for the Open Pits Operable Unit was approved in 2022 and the RI was approved in early 2023. No further action was taken for the Open Pits Operable Unit after a public comment period on the proposed plan concluded in mid-2023.Next Steps for South Maybe Canyon MineRemedial InvestigationFeasibility StudyProposed PlanPublic Comment PeriodRecord of Decision

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STATE REMEDIAL ACTION SITESThese sites differ from CERCLA remedial action sites in that measures taken in response to degradation are in accordance with the Idaho Environmental Protection and Health Act (Idaho Code § 39101 et. Seq.). South Rasmussen Mine Active Status: RA and Remedial MonitoringIn 2023, P4 continued groundwater and surface water monitoring (including the PRB and Point of Compliance monitoring wells) and continued operation of the leachate collection system in Watershed B. In 2023, P4 also nalized plans for completing reclamation of the South Rasmussen Main Pit and nal reclamation will commence in summer 2024. Reclamation of the South Rasmussen Main Pit includes construction of an evapotranspirative or “store and release” cover. Efforts in 2024 will include hauling and placing a 2-foot-thick layer of alluvium/colluvium overlain by a 1.5-foot-thick layer of growth medium. Digital surface designs will be uploaded to GPS equipped dozers to control placement of alluvium/colluvium and growth media. Erosion and sediment controls such as hydromulch, straw wattles, and rock lined runoff ditches will be incorporated into the reclamation surface. Reclamation seeding will be completed using a combination of hydroseeding, drill, and broadcast methods to optimize vegetation establishment.As part of the Rasmussen Collaborative Alternative, overburden from the Rasmussen Valley Mine was used to partially backll the open pit at South Rasmussen Mine. This alternative eliminated the need for a permanent external overburden pile at Itafos’ Rasmussen Valley Mine.Next Steps for South Rasmussen MineRemedial Action PlanInterim Monitoring Remedial Action DesignRemedial Action ConstructionLong Term MonitoringSouth Central Rasmussen Ridge Mine AreaActive Status: Preliminary Remedial Design; RA; O&MIn 2023, interim operations and maintenance activities continued. Rip Rap was installed in some impacted seep areas along No Name Creek to keep wildlife away. Major reclamation activities cannot occur until the mining haul road, which is being used to haul ore from the Rasmussen Valley Mine, is able to be taken out of service in a few years.Next Steps for South Central Rasmussen Ridge Mine AreaRemedial Action PlanInterim Monitoring Remedial Action DesignRemedial Action ConstructionLong Term MonitoringSelenium was rst identied as a potential issue in the 1990s, and as a result, reclamation processes were updated at South Central Rasmussen Ridge Mine Area during mining. Areas that were reclaimed by historical reclamation practices (prior to selenium being identied as an issue) are the primary areas requiring further remediation activities.you know?you know?

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Your state and federal agencies can serve in several roles during the ongoing site remediation efforts currently being implemented in the resource area. One of the roles is serving as a lead agency Project Manager. Depending on the ownership of the remedial action site, among other factors, a Project Manager will be chosen from the lead agency to direct the remediation efforts. Other agencies can then serve in supporting roles in the process. This can result in a collaborative effort in which several agencies work together on several different remedial action sites in the resource area. Other roles include the review of reports, plans, and data collected to ensure chosen remedial efforts will align with regulatory requirements, remedial action site visits and inspections, environmental monitoring, and public outreach and involvement. Below is a list of these agencies and some of the possible roles served in the resource area.GOVERNMENT AGENCIES AND THEIR POSSIBLE ROLES IN THE RESOURCE AREAUnited States Department of the Interior Bureau of Land Management - Project Managers - Plan and data review to verify alignment with regulatory requirements - Site Visits and InspectionsUnited States Environmental Protection Agency - Project Managers - Plan and data review to verify alignment with regulatory requirements - Public Outreach and Involvement - Site Visits and Inspections - Environmental MonitoringUnited States Department of Agriculture Forest Service - Project Managers - Plan and data review to verify alignment with regulatory requirements - Public Outreach and Involvement - Site Visits and InspectionsUnited States Fish and Wildlife Service - Plan and data review to verify alignment with regulatory requirementsUnited States Geological Survey - Environmental MonitoringIdaho Department of Environmental Quality - Project Managers - Plan and data review to verify alignment with regulatory requirements - Public Outreach and Involvement - Site Visits and Inspections - Environmental MonitoringIdaho Department of Lands - Plan and data review to verify alignment with regulatory requirements - Site Visits and InspectionsShoshone-Bannock Tribes - Plan and data review to verify alignment with Tribal Treaty Rights and Tribal Uses

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In addition to clean-up of historic mine sites in the Southeast Idaho Phosphate Resource Area, there are several active mines and more in developmental stages. J.R. Simplot Company, Itafos, and P4 Production, LLC currently operate open pit mines within the resource area. Mining practices today have changed and evolved throughout the years. Through advancements in environmental monitoring techniques and networks, companies and agencies now have a better understanding of the environmental risks associated with phosphate mining and how to mitigate them. When a new mine is permitted, many things need to take place before mining can begin. A Mine and Reclamation Plan (MRP) is developed and submitted after a company obtains federal and/or state mineral leases. This plan typically includes things like mine design, water and other environmental management, BMPs (best management practices) to be implemented, and reclamation design. Agencies then use that information to participate in the preparation of an Environmental Impact Statement (EIS). An EIS must be completed to comply with the National Environmental Policy Act by analyzing the potential environmental impacts of the proposed mining and reclamation operations along with reasonable alternatives. After careful analysis of ndings in the EIS, a plan is selected, and ROD is issued by the lead agency. This document, along with the MRP becomes the roadmap of approved actions for the future mine. In most cases, mining companies have permits and administrative agreements with other agencies. For example, DEQ issues Points of Compliance Determinations which essentially establish a perimeter whereby groundwater quality standards must be met as groundwater moves away from a mine. As mentioned above, mining today looks quite different than it did decades ago. For example, in the old days of phosphate mining in southeast Idaho, miners did not know the release of selenium was a potential contaminant that could leach into groundwater, ow through streams, migrate through sediment, and even be taken up into vegetation and consumed by animals. Overburden and other waste rock was often piled near the pit and left there where it was exposed to air, rain, and snow where the contaminant could then migrate through the environment. Today, we know the location of the specic layer of selenium-rich rock within the Phosphoria Formation known as the center waste shales. This waste rock is selectively handled and placed back in the pit and covered with other overburden after mining is complete. By placing the waste rock at depth in the pit where reducing conditions are present, chances of transport are greatly minimized. In addition, state-of-the-art cover systems have also been approved as another form of mitigation for the active mines, as well as using them as remedial actions at historic sites. In recent years, several mining companies have entered into agreements or land exchanges in order to place overburden from new mines into old open pits to prevent the creation of new external overburden piles. Today’s mines also have extensive environmental monitoring networks that include sampling of groundwater, seeps, springs, stormwater, air, aquatic habitat, and sh. To learn more about active mining or the remediation process at old mine sites, come see us at our booth at the Caribou County Fair.

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Ballard, Enoch Valley, and Henry MinesLinda MeyerBallard MineEPA Region 10, Seattle Ofce206-553-6636Meyer.Linda@epa.gov Lynne HoodEnoch Valley and Henry Mines EPA Region 10, Idaho Operations Ofce206-384-0363Hood.Lynne@epa.govConda/Woodall Mountain MineStan Christensen DEQ Pocatello Regional Ofce208-236-6160Stan.Christensen@deq.idaho.gov Lynne HoodEPA Region 10, Idaho Operations Ofce206-384-0363Hood.Lynne@epa.govChamp, Mountain Fuel, North Maybe, Smoky Canyon, and South Maybe Canyon MinesBrian DeekenU.S. Forest Service 208-236-7516Brian.Deeken@usda.govGeorgetown Canyon and South-Central Rasmussen Ridge MineStan Christensen DEQ Pocatello Regional Ofce208-236-6160Stan.Christensen@deq.idaho.gov Gay MineIsaac KellyEPA Region 10, Seattle Ofce 206-553-0062Kelly.Isaac@epa.govSouth Rasmussen MineNick NielsenDEQ Pocatello Regional Ofce 208-236-6160Nick.Nielsen@deq.idaho.govTribal ContactKelly Wright Shoshone-Bannock Tribes208-478-3905kwright@sbtribes.com CONTACT INFORMATIONSend a note to Kelly Greenkgreen@northwindgrp.com

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