Accountable for our Water Use

DMA: Water

Detour Lake Mine is surrounded by many creeks and lakes within the Detour River watershed. As one of the main industries in the watershed, and a significant user of water for exploration, mining, mineral processing and domestic purposes, we are very conscious of our potential impacts on local water bodies.

Although numerous, many of the surrounding sub-watersheds are small with limited supply and capacity. Our water management strategy takes this into account, and focuses on four key areas:

  • Minimizing our fresh water intake,
  • Balancing demand, so we don’t use more water than needed,
  • Maximizing water recycling and,
  • Discharging treated water, if needed, under our rigorous Ontario Ministry of Environment and Climate Change permit conditions that protect aquatic life.

From the start of operation, we developed and have continually improved a comprehensive water balance tool for the entire property.

By diligently managing this balance, we achieved our goal of running a zero discharge operation for the first four years of operation. Water balance tracking is a key operational tool that helps us ensure that sufficient water is available for process supply and that our storage facilities have adequate capacity while avoiding excess storage. Although we have provincial permits in place to discharge if required, so far all of our process water has been recycled.

As part of our environmental protection strategy, we have implemented one of the most comprehensive surface and ground water monitoring programs in the province, with more than 50 surface water stations and 90 groundwater wells monitored for quality, water level and flow. Provincial environment permits require regular reporting of the results. We also involve our Aboriginal partners in environmental monitoring and provide annual reports to them.

As mine site development progresses, we continually refine our water balance model, using increasingly sophisticated tools, to help us accurately track and predict water use and future needs and adopt the most efficient water management approaches.

2016 Performance

G4-EN10

As expected, our water consumption continues to increase as our production, site footprint and workforce grow. Detailed water use from individual sources is reported to the Ministry of Environment and Climate Change through its online Water Taking Report System further to the conditions of each of our Permits to Take Water.

97% (16.1 Mm3) of the water used in processing in 2016 was recycled from the tailings management area. The remaining 3% is fresh water sourced from East Lake and used for the delicate reagent mixing process. Water withdrawn for domestic use and consumption at our employee camps totaled 86,624 m3.

Water for dust suppression is 100% recycled from mine dewatering activities and runoff collection. Recycling water in both the open pit and the process plant reduces stress on the natural environment and reduces our demand for storage areas and treatment requirements.

Detour Process Water Used

Water Withdrawal by Source

G4-EN8, EN9
Source 2016 2015
Reclaimed water from tailings management area (Mm3) 16.5 15.9
East Lake fresh water for industrial use (m3) 544,807 427,649
Groundwater wells for domestic use in construction camp (m3) 40,421 30,862
Surface water for domestic use in permanent camp (m3) 46,203 30,725

Water Discharges (Effluent)

G4-EN22

For the fourth year in a row, we maintained our zero discharge status, meaning that no process water was released to the environment.

The only release was treated domestic sewage from the employee construction and permanent camps. Each camp has its own domestic sewage treatment plant. All discharged water met the criteria set in the environmental compliance approval issued by the Ministry of the Environment and Climate Change.

Treated Domestic Sewage Discharge (m<sup>3</sup>)

Case Study

Every Drop of Water Counts

Protecting the environment is always top of mind at Detour Gold. We are committed to maintaining the natural conditions of our local watersheds and minimizing our impact on aquatic life and traditional practices.

Managing water is a critical part of our operation. From the start of production, we’ve maintained a closed loop water management system, which means that we recycle our process water from the tailings management area (TMA) to supply the plant. No process water has ever been discharged.

Currently, our permit from the Ontario Ministry of the Environment and Climate Change allows us to discharge naturally occurring water collected from the open pit and runoff collection ponds into East Creek, if necessary. The water that would be discharged would not have been used in the process plant or come in contact with tailings. While we have not released any water so far, we may need to start in the near future given heavy rainfall and our gradually increasing footprint. This will help us maintain the delicate water balance it takes to run our operation safely.

To accommodate a larger volume of contact water, we embarked on a project in 2016 to select a new discharge location. Using a collaborative approach, the project involved field studies and a review of alternatives as well as consultations with regulators and our Aboriginal partners. The consultation process is ongoing as we work together to find the most appropriate location – one that balances operational needs while protecting aquatic life and the environment.

The Business Case

for proactive water management

  • Working together with local communities builds trust and respect, and maintains our social license to operate.
  • A collaborative approach that seeks early input often means the community is onboard and helps ensure we understand any potential social and environmental risks before they become serious issues.
  • Removing naturally occurring water from our overall inventory reduces the risks associated with storing large amounts of water.
  • Minimizing storage requirements reduces the cost associated with constructing a larger containment area. Every metre a dam is raised costs approximately $10 million and only provides an additional 2.5Mm3 of storage space. Balancing our operational needs with containment costs and environmental stewardship is the key to success.