Month: March 2025
THE DIRT: Completion of Priority Cleanup Activities in the Ninemile Basin
All priority cleanup activities in the East Fork Ninemile (EFNM) Basin have been successfully completed, marking a significant milestone in environmental cleanup efforts. The EFNM Waste Consolidation Area (WCA) has reached capacity, and final closure activities are now underway. As this phase concludes, monitoring efforts will continue to assess the effectiveness of the remedial actions.
The Ninemile watershed, located near Wallace, Idaho, spans approximately 12 square miles, with Ninemile Creek extending 7 miles from its confluence with the South Fork Coeur d’Alene River (SFCDR) to the EFNM Creek headwaters. This area has been significantly impacted by historical mining activities dating back to the late 1800s, which introduced elevated metal concentrations into sediments, soil, and water.
In 2012, the Interim Record of Decision Amendment (RODA) identified 36 legacy mining sites contributing to metal contamination in the Ninemile Basin. These sources included waste rock dumps, mine workings, fill areas, and jig tailings piles. Initial, limited cleanup efforts by the Coeur d’Alene Tribe and Idaho Department of Environmental Quality (DEQ) began in the 1990s, followed by remediation of the Rex No.2/Sixteen-to-One Mine between 2002 and 2007. In 2014, the Coeur d’Alene Trust launched extensive remedial actions (RAs) in line with the work outlined in the RODA. Through an adaptive management approach, the U.S. Environmental Protection Agency (EPA) collaborated with stakeholders to prioritize and implement RAs across the Upper Basin, with the Ninemile Basin designated as an initial focus area due to its significant contribution of dissolved and particulate metals to area waterbodies.
Since 2014, cleanup work in the EFNM Basin has been ongoing. These efforts included the design and development of the WCA and remediation of major sites such as the Interstate Callahan rock dumps, Success Complex, Interstate Millsite, Lower EFNM Creek, Tamarack Complex, and Dayrock Complex. In total, approximately 1,545,000 cubic yards of waste were excavated and hauled to the EFNM WCA for placement and compaction, and approximately 15,000 linear feet of stream were reconstructed. The EFNM WCA generated approximately 350,000 cubic yards of rock and 375,000 cubic yards of soil for the Ninemile Basin remedial actions. The EFNM WCA’s strategic location near contamination sources resulted in an estimated $8.5 million in transportation cost savings while minimizing traffic disruptions to local communities. By late 2024, the EFNM WCA reached capacity, and final cover design was completed. Construction of the final cover system is anticipated for completion in 2025 and 2026, signifying the culmination of key cleanup efforts.
To ensure the long-term success of these remedial actions, the Basin Environmental Monitoring Plan (BEMP) was developed in accordance with the 2002 ROD and 2012 RODA. The BEMP provides a framework for assessing the effectiveness of cleanup activities, guiding the collection, analysis, and interpretation of environmental data. In the Ninemile Basin, RA effectiveness monitoring will evaluate progress toward remediation objectives, including water quality improvements and ecological responses. Monitoring efforts, which will continue for at least five years, will determine whether performance goals have been met. If goals are achieved, monitoring will transition to a site-wide program; if not, further assessments will be conducted to identify additional recommendations for achieving long-term environmental objectives in the Ninemile Basin.
The Dirt is a series of informative articles focused on all aspects of cleanup efforts associated with the Bunker Hill Superfund Site. Our goal is to promote community awareness of contamination issues, to provide tools for protecting public health, and to keep the community informed of current and future cleanup projects. The Dirt is a group of committed and local experts from multiple agencies including the Basin Environmental Improvement Project Commission, Panhandle Health District, Shoshone County, Silver Valley Economic Development Corporation, and the Idaho Department of Environmental Quality.
THE DIRT: Property Disclosures
How do you know if a property is safe from environmental hazards when you purchase it? In most communities, you would not. To make that determination, a property owner would have to pay to have a Phase 1 environmental audit performed, which can be a burdensome expense. One of the benefits of living within the Bunker Hill Superfund Site (BHSS) is that procedures are in place to maintain environmental records on properties within the site and to make those records available free of cost. The BHSS is a geographic region that was impacted by lead and other heavy metals from historic mining, milling, and smelting practices. Sampling for heavy metals within the site began in the 1980s, with cleanup efforts beginning in 1986.
Cleanup measures for the BHSS are unique because contamination is so widespread and so deep in some areas that total removals could not be completed. Rather, partial removals were performed, and clean barriers ranging in depths from six to twelve inches were installed over the remaining contaminants. Because the success of this cleanup depends on the protection of these fragile barriers, the Institutional Controls Program (ICP) was established under Panhandle Health District to oversee the installation and maintenance of these barriers as well as general dirt disturbance activities. The ICP also maintains records for all superfund-related data collected at the BHSS. This data includes soil sample results, records of any remedial actions taken on a property, copies of any ICP permits issued for that property, and additional helpful information.
Having a local ICP allows our communities to conduct commerce and sell properties without the requirement of environmental audits, a cost that private property owners would bear. Property owners are legally responsible for maintaining the depth and integrity of their barriers, so recording any disturbance is essential for documentation. If a property is listed for sale, a copy of all permits and records are provided to the potential buyers. If there have been changes to the property without the proper documentation, this could hold up or impact the sale. Dirt disturbance activities not permitted or inspected can result in compromised barriers. Compromised barriers create a health risk for residents, especially for children and pregnant women. Sellers, realtors, and landlords are legally required to provide property disclosures that detail information about a property’s barriers and provide a record of documented dirt disturbance activities. Disclosures are free of charge and can easily be requested online at https://cdabasin.idaho.gov/real-estate-property-disclosures/.
The Dirt is a series of informative articles focused on all aspects of cleanup efforts associated with the Bunker Hill Superfund Site. Our goal is to promote community awareness of contamination issues, to provide tools for protecting public health, and to keep the community informed of current and future cleanup projects. The Dirt is a group of committed and local experts from multiple agencies, including the Basin Environmental Improvement Project Commission, Panhandle Health District, Shoshone County, Silver Valley Economic Development Corporation, and the Idaho Department of Environmental Quality.
