Mining Magazine > Panorama > Veolia awarded Trevali contract

Veolia Water Solutions & Technologies Canada has been awarded a contract by Trevali Mining Corporation for the design and supply of a 1,000m³/d effluent treatment plant to serve its Halfmile zinc-lead-silver-copper mine in New Brunswick, Canada. The new zinc-lead-silver-copper mine is situated 60km south of Bathurst and commenced production in January 2012.

The scope of this fast-track design-build project includes the entire treatment plant as well as the construction of the building. The treatment plant will provide precipitation, decantation and filtration, along with pH correction to provide a treated mine effluent that meets the Canadian Council of Ministers of the Environment (CCME) Water Quality Guidelines for the Protection of Aquatic Life.

Paul Keller, Trevali's vice president of operations, said: “Trevali is pleased to be working with Veolia in providing a compact turnkey water treatment solution for the Halfmile mining project. Having the peace of mind of working with a major solution provider allows the company personnel to focus on mine development and production activities.”

The plant incorporates metals precipitation using the ACTIFLO TURBO, a high-rate, small footprint clarification process. The ACTIFLO process uses sand-ballasted settling and a TURBOMIX draft tube reactor that allows for a very compact design with high overflow rates and short detention times. This design enables the unit to perform well under dynamically changing flow rates without impacting final effluent quality. By combining the proprietary Hydrex reagent to magnesium hydroxide, the solids produced in the ACTIFLO unit will be larger than sodium sulphide, which facilitates downstream filtration.

After clarification, the water undergoes sand filtration to remove any remaining solids, followed by pH correction. Also, the instrumentation and automation package permits remote monitoring of the entire water treatment plant, which is a major benefit for the operation of the plant.

The building will be a 15m x 22m steel building with all ancillary services, including a 1.8t overhead crane and water quality laboratory.

The plant is currently in the final construction phase. Trevali has been constructing the Halfmile project civil works since March 2011, and commenced production of the water treatment plant in January 2012, with a planned production ramp-up to a rate of 1,800t/d.