- Mining waste, tailings, and contaminated soils that may be found will be removed and taken to an approved repository outside of the Silver Bow Creek and Blacktail Creek corridors.
- Municipal waste, household waste, timbers, and other construction debris not suitable for re-use, if found, will be disposed of at an appropriately permitted facility.
- The stormwater sedimentation bay will be sized to capture the 6-month, 24-hour Type I Soil Conservation Service (SCS) design storm.
- Additional storage volume will be provided for management of accumulated sediments.
Remedial Construction Activities
Grove Gulch is one of several gulches in Butte that may have been used to dispose of milling and mineral processing wastes, allowing that material to flow down the drainage and into Blacktail Creek. The remedy will include construction of a sedimentation bay and vegetated swale to reduce the amount of contaminated sediment and metals that reach Blacktail Creek and thereby improve the quality of water in the creek. The remedial construction activities will be performed by Atlantic Richfield Company and would include:
Excavation & Disposal
Any tailings, wastes, or contaminated soils found beneath the footprint of the sedimentation bay and vegetated swale will be excavated and hauled to a repository. Some excavated materials, including clean topsoil, will be reused to complete reconstruction of the site.
Sedimentation Bay and Vegetated Swale
A sedimentation bay and vegetated swale will be installed parallel to Lexington Avenue, just south of I-15/90, and capture stormwater from the Grove Gulch drainage. Maintenance of the bay will include removal of captured sediments and disposal of the sediments at a repository.
All areas disturbed during construction activities will be regraded and vegetated. For maintenance purposes, an access road and turnaround area will be constructed.
End Land Use
The Grove Gulch project area will not provide for public access or recreational use. However, it will be landscaped and includes planting of native trees, shrubs, and riparian species.