The Challenge
Faro Mine was once the largest open pit lead-zinc mine in the world. Today, it is the site of one of the most complex abandoned mine remediation projects in Canada. The mine spans 25 sq. km, an area roughly the size of the city of Victoria, British Columbia. It is located in south-central Yukon, near the town of Faro, on the traditional territory of the Kaska Nations, and upstream from Selkirk First Nation. It was determined that there was an immediate need for a draw down of water from the Faro pit to ensure there would not be a breach of the mine impacted water. The existing plant was also in need of repair at which time it was determined to install and new treatment facility to continue to draw down the pit water while still meeting strict environmental guidelines.
The Project
The client required a solution for the treatment of Faro pit water, but also having the flexibility to treat other source waters found on the Faro property. Due to rising levels in the Faro pit, and the poor condition of the existing treatment facility, it was deemed necessary to develop a treatment strategy to allow for the continuation of treatment of the Faro pit as part of the overall remediation of the Faro property. After extensive testing within Veolia’s lab facilities, a treatment scheme was presented to the consulting firm overseeing the site activities in 2014.
The Solution
For the rehabilitation of the highly contaminated Faro Pit Veolia designed and built a temporary installation for the treatment of heavy metals. Test work performed by Veolia also confirmed the plant would be able to treat other source waters at site or a combination of three source waters. This testing also confirmed chemical optimization that coagulant was not required due to ferrous iron already present in the water.
- Modular Reactors with aeration for grids iron oxidation
- Modular Reactors for Lime addition and pH control
- Removal of TSS and metals using ACTIFLO High-Rate Clarification
- Chemical feed containers, electrical containers
- Building including mechanical and electrical installation
The Results
The treatment plant was executed in 2 contracts. First contract was for the equipment supply to allow for quick manufacturing of the treatment system being built at Veolia’s manufacturing facility in Montreal. Equipment contract was issued in April 2014, with first equipment delivery in June 2014. The Design Build contract was issued in May 2014 with construction completed in October 2014.
Plant performance not only met all heavy metals discharge criteria, but also allowed for longer treatment seasons and larger draw downs of the Faro pit. The system is still in operation today.
The Client
The Yukon Government, acting as an agent for the Government of Canada and a large consulting firm working together to assess the needs to evaluate the Interim water treatment needs at the abandoned Faro Mine site in 2014.
Key Drivers
A reliable, robust, and proven small footprint technology was required for the treatment of heavy metals for discharge to the environment. This needed to be completed in a very expeditious manner to prevent a possible breach of the existing pit water to the local environment.