What happens when there is too much water at a mine site? Our Red Dog Operations, one of the world’s largest zinc mines, is located in a region where there is an average of 48 cm of precipitation each year, much of which falls as snow. While this amount of precipitation may sound modest in comparison to some regions, at Red Dog this translates into large volumes of precipitation and runoff accumulating into the Tailings Storage Facility (TSF) where we direct all of our contact water. The operation stores nearly five billion gallons (20 million cubic metres) of water on-site, which is roughly equivalent to 7,500 Olympic-sized swimming pools. All of this water must be monitored and managed, including treatment, before it can be discharged.
While a portion of water stored in the TSF is required for operating the mill, over half the water stored is not needed. Continually building higher dams to store water is not a preferred long-term solution. In addition, high costs of construction and additional permits are needed to expand dams. That’s why finding ways to increase Red Dog’s ability to safely discharge water and reduce the volumes stored in the TSF is the most sustainable long-term solution.
Managing Water in the Long Term
To reduce the risks and costs associated with storing excess water, Red Dog has set a goal to reduce excess water from five to two billion gallons, which is the volume actually required for mill operation. To reach that goal, Red Dog began evaluating three different strategies in 2016. The strategies focused on preventing runoff water from entering the TSF and increasing the treatment of existing water. These strategies will be assessed and the most practical strategy is planned to be selected and implemented beginning in 2018.
Managing Water in the Short Term
In 2016, Red Dog also focused on achieving short-term goals related to water management, with engineers working to find innovative ways to optimize existing infrastructure. For example, the pump arrangement in the TSF was reconfigured to increase the amount of water pumped through the sand filters by 10% while ensuring that water quality standards continued to be met before the water is discharged. This increase helped lower the amount of water stored in the TSF and reduced the risks associated with storage.
Ongoing Water Planning
Red Dog maintains an integrated water management plan and site-wide water balance, which are central components of the water management strategy. This plan is used as a decision-making tool to evaluate water management performance, provide water data for external reporting, and communicate our water stewardship practices to local communities.
“Red Dog’s integrated water management plan and water balance are used as tools for collaboration between departments, preventing and being prepared for possible risks, and for helping us to meet Teck’s sustainability goals of having a positive influence on water quality,” says Chad Novotny, Tailings and Water Management Engineer, Red Dog Operations.