The Site is between the communities of Stockton and Tooele in Tooele County, Utah. It comprises over 150 acres of tailings ponds and waste deposits that were generated by a large milling facility that operated from the 1920s until 1979. The tailings and waste left behind are over 15 feet deep and contain high levels of lead and arsenic. The Site includes large tailings impoundments which hold water after precipitation events. Winds consistently carry contamination off-site and the area has been heavily trespassed for decades.

1. Regrade the tailings impoundments so that large pools no longer form on the waste deposits.
2. Cover the tailings deposits that are not vegetated with 10 inches of rocky soil / gravel.
3. Apply seed mix to capped areas.

• Collect and process existing datasets.
• Determine cost and suitability of nearby cap material.
• Determine depth of contamination outside the failed berm.
• Determine depth of contamination at a few locations within the historic berms.

• A total of ten test pits were excavated August 16, 2021 to determine the depth of waste deposits within the historic berms and outside the failed containment berm.
• Waste deposit material and native soils from test pits were screened with an XRF analyzer for lead and arsenic concentrations. 
• Processed and mapped datasets. 

• Prepare an Action Memorandum to conduct a Time-Critical Removal Action.
• Secure legal access to the Site and develop operational plans.

EPA determined that conditions at the Site present a threat to public health and the environment and meet the criteria for initiating a removal action under 40 CFR 300.415(b)(2) of the National Contingency Plan. 

EPA signed and funded an Action Memorandum to:

• Regrade ~160 acres of mill tailings and historic impoundments to direct surface runoff away from the contaminated area. Lined and rocked drainage ditches will be constructed as necessary to control runoff that originates on the tailings area.
• Cap the tailings with local alluvium and/or gravel. Compost or other organic material will be applied to support vegetation to the extent practical.
• Construct erosion control structures to prevent future wind and surface water erosion. Limit off-road vehicular use.

EPA also secured legal access to the Site with the current property owner.

• Begin to mobilize personnel and equipment to the Site.
• Install gates and signage to restrict public access during construction.
• Begin to re-grade the southeast tailings area.
• Begin to address physical hazards (falls hazards, areas at risk of collapse) at the former mill site

During this Operational Period, EPA's response team mobilized personnel and equipment the site, installed temporary gates and signage at the dominant access points and set up the Site office trailer.

The Team began regrading the non-vegetated tailings in the southeast area of the Site and started addressing physical hazards nearest the Site office trailer.

The next Operational Period is November 15 to November 21, 2021. The Response Team plans to:

• Continue to mobilize personnel and equipment to the Site.
• Finalize subcontracts for cover material and water for dust suppression.
• Continue to re-grade the southeast tailings area.
• Continue to address physical hazards (falls hazards, areas at risk of collapse) at the former mill site.
• Collect seeds from surrounding vegetation.

• Maintain dust suppression.
• Identify and address physical hazards at the Site to support Operations.
• Continue to remove impoundments in grids E06-07, F05-08, G04-08, H04-08, I05-07 and J05-06.
• Establish temporary access and a haul road to the gravel pit adjacent to the Site.
• Plan to cover the mine waste from the west to the east working away from the gravel pit.

The Response Team identified a set of unsafe concrete pillars and railcar platform along a large retaining wall at the facility. This structure was removed to facilitate Site Operations and the material that was generated is being assessed for future use on Site.

The crew continued to use bulldozers to remove the tailings impoundments and prepare those areas for the gravel cap. A flock of birds landed and spent the day in one of the remaining pools.

The team mapped the edges of vegetation to establish its work zone, delineated work grids and initiated construction of a haul road road to the  gravel vendor to the west of the Site.

• Conduct the second UAS flight to collect imagery and survey data.
• Continue removing the tailings impoundments.
• Continue constructing the haul road to the grave pit and begin construction of 3 access points from the haul road to the tailings deposits.