Operations, maintenance, & monitoring services at gold mine

Challenge

Carson Hill is a historic mining district where gold has been mined since the mid-1800s. The Carson Hill Gold Mine in Calaveras County, California was an open pit gold mine that operated in the late 1980’s. The mine consists of a 64-acre open side cut, 3 former heap leach piles 3 waste rock disposal facilities, a flotation circuit and an SX/EW plant including one tailings storage facility, two heap leach facilities, multiple waste rock dumps, and four open pits.

The mine’s Waste Discharge Requirements require collection and management of mine-impacted seepage and drainage from waste management units. Collection water is processed through a greensand filter, reverse osmosis water treatment plant and discharged under an NPDES permit.

Solution

Our role:

• Operations and maintenance (O&M) of the seep and drain collection systems.
• O&M of the RO water treatment plant.
• NPDES permitting and compliance.
• Groundwater and surface water monitoring and reporting.
• Geotechnical slope stability surveillance of the sites waste rock disposal facilities.
• Stormwater BMP maintenance and compliance sampling.
• Database management using EQuIS environmental data management software.

Highlights

• Successful year after year collaboration between SLR, client field teams, and office managers.
• Engineered and installed a greensand filter for the removal of manganese in the waste stream prior to RO filtration.
• Prepared Operations, Maintenance, and Monitoring Plan to provide a holistic document for operators, field leaders, and managers.
• Implemented a site-specific health and safety plan in collaboration with BHP site superintendent.
• Engineered, coordinated, and performed CQA for geomembrane liner replacement of 3 waste management unit (former heap leach piles).

Impact

SLR has and continues to support BHP with O&M and environmental compliance during the closure process with O&M and environmental services.