Reducing Fresh Water Use to Almost Zero
Though mining is inherently a water-intensive business, Goldcorp’s commitment to its environmental vision, Our Planet. Our Choices. Our Legacy., places high priority on water conservation and preservation. Across all operations, the company is tapping new potential to reduce and recycle.
For example, just a few years ago, average fresh water usage at Porcupine Gold Mines’ (PGM) Dome Mill, measured as a percentage of total used for processing ore, was 22%. But PGM was determined to drop this number to as close to zero as possible, and bring recycled water use up to 100%, to positively impact the environmental footprint as well as cut operating costs over the life of the mine.
Traditionally, fresh water from Porcupine Lake was used for processing ore. PGM’s objective was to use reclaimed water across the board, which would both conserve precious resources and reduce the need to treat and discharge water from the Effluent Treatment Plant.
To ensure this aim was feasible without detrimental effects on ore processing, Goldcorp embarked on a three-month trial period with positive results: zero fresh water was used and no negative effects ensued.
Modifications were then made to Dome Mill for the long-term, including new lines, valves and repurposing old water tanks. The water lines from Porcupine Lake to the mill and fire tank were updated to ensure continuous pump operation to prevent water lines from freezing in winter, and fresh water availability year-round for emergencies, such as fires.
Today, refurbished freshwater tanks in the mill are used to store reclaimed water, with flow and levels automatically managed with mag meters and programmable control valves.
The total cost of modifications was approximately $170,000, with considerable return on investment. Average monthly fresh water consumption is down more than 100,000 cubic metres and water treatment costs have dropped by approximately $500,000 per year.
An equally impressive upshot is that fewer dam lifts are required over the life of the mine, typically required every three to four years. Each dam raise costs approximately $5 to $6 million; PGM did not need to lift its dam in 2014 as previously scheduled.
Congratulations to the team at the Dome Mill at Porcupine Gold Mine for reducing their water usage and environmental impact in an innovative way.