Veolia Water Solutions & Technologies Canada is currently engaged in a project for the design and supply of a 1,000-m3/d effluent treatment plant to serve Trevali Mining Corp.’s Halfmile zinc-lead-silver-copper mine in New Brunswick. The new zinc-lead-silver-copper mine, situated 60 km south of Bathurst, commenced production earlier this year.

The scope of the fast-track design-build effluent treatment project includes the entire treatment plant as well as the construction of the building. The plant will provide precipitation, decantation and filtration, plus 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.

According to Paul Keller, Trevali’s vice president of operations, the plant incorporates metals precipitation using ACTIFLO Turbo, a high-rate, small-footprint clarification process. The process uses sand-ballasted settling and a draft tube reactor that allows for a 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. After clarification, the water undergoes sand filtration to remove any remaining solids, followed by pH correction. Instrumentation and automation features permit remote monitoring of the entire water treatment plant.

Trevali has been constructing Halfmile’s civil works since March 2011, and began production at the underground operation in January 2012, with a planned production ramp-up to a rate of 2,000 mt/d.

Trevali has two advanced-stage polymetallic (zinc-lead-silver-copper) deposits in Canada and Peru—Halfmile and Santander, respectively. In Canada, Trevali owns the Halfmile mine and Stratmat polymetallic deposit in the Bathurst Mining Camp of northern New Brunswick, and the past-producing Ruttan copper-zinc mine in northern Manitoba.