Case Study as part of a Web-based Technical and Regulatory Guidance

Stull Yard
Shoshone County, Idaho

1. Site Information
1.1 Contacts
Paula A. Lyon
Telephone: 509-535-7225
E-mail: [email protected]

1.2 Name, Location, and Description
Longitude: 116° 04' 14" west
Latitude: 47° 30' 38" north

Stull Yard is a “bone yard” for the Sunshine Silver Mine that includes accumulated mine waste from over 100 years of operations. Also included at the site are solvents from drum-crushing operations and cupels/crucibles from laboratory assay operations. Approximately 860 tons of waste are located at the yard. The site is located near Kellogg, Idaho in Shoshone County.

2. Remedial Action and Technologies
Secondary contaminants include lead, mercury, and zinc. Resource Conservation Recovery Act (RCRA) is the regulatory driver for cleanup of the site. There is 859 tons of waste to be remediated. The site cleanup goal is mitigation of human health risk.

The primary treatment technology at the site is excavation and disposal at a treatment/storage disposal facility (TSDF) for stabilization to meet land disposal restrictions (LDRs). Secondary treatment technologies include capping/covers/grading and chemical stabilization. The finite solution is expected to be a one-time removal action.

3. Performance
Confirmation sampling was conducted to meet state risk-based cleanup standards, followed by capping to reduce potential for exposure to site workers at a commercial/industrial site. Removed waste was transported for off-site treatment via stabilization and disposal at a TSDF to meet LDRs/universal treatment standards for underlying hazardous constituents.

4. Costs
The capital costs were $180.73/ton for transport, treatment, and disposal. There are no operations and maintenance costs.

5. Regulatory Challenges
Challenge to the regulatory agency was limiting the scope of the investigation/remedial action to the previous RCRA enforcement action. A work plan had been approved by the regulatory agency prior to implementation.

6. Stakeholder Challenges
There were no public issues or concerns regarding this action.

7. Other Challenges and Lessons Learned
Due to an impending property transaction and an aggressive schedule, the work was performed from October to March during severely inclement weather conditions, which created various logistical difficulties (e.g., frozen waste required significantly larger backhoes to excavate the frozen materials). There were also delays in transportation due to poor road conditions.

8. References
No information available.