When BioteQ became involved in the site in 2001, the Caribou mine was not operating; however, the site required ongoing attention and remediation in water management and treatment. In 2001, BioteQ financed, constructed and operated a BioSulphide® plant to meet strict water quality requirements and recover zinc and other heavy metals into a concentrate, upstream of a lime treatment plant. The plant was started up in November 2001 and by January 2002 had reached a steady state.
The BioSulphide® plant operated throughout 2002 and demonstrated the ability of the technology to recover metals into a high grade product, and produce treated water that met strict water quality regulations. During 2002, the plant recovered nearly 35 tonnes of zinc concentrate.
The BioSulphide® treatment process significantly reduced lime reagent consumption and sludge production in the lime plant. By removing the heavy metals prior to lime treatment, the process reduced the long term sludge storage liabilities and costs that are typically associated with lime treatment.
The plant concluded operations in 2003, having successfully demonstrated the commercial scale of the technology. BioteQ continued to operate water treatment plants and provide environmental management services at both Caribou and the nearby Restigouche mine site until 2007, including operation and retrofit of a low density sludge water treatment system together with a settling pond, the conversion of an LDS plant into a new HDS lime plant, and remediation of a sizeable deposit of old tailings.
Management of the site was transferred to new owners, Blue Note Metals Inc., in 2007.
The application of BioteQ’s technology at this site provided economic and environmental benefits. The plant: