Abstract
The Gibraltar Mine, a copper-molybdenum operation in British Columbia, Canada, faced a challenge with the sum of nitrate and nitrite (nitrate+nitrite-N) in its Tailings Storage Facility (TSF) exceeding the permitted discharge criterion of 10 mg/L (as N). To address this, Gibraltar Mines Ltd. collaborated with Ensero Solutions to explore treatment options, identifying in-situ microbial denitrification as the most viable solution.
In June 2023, the mine successfully implemented this treatment approach by adding 603 m3 of denatured ethanol to the TSF, stimulating the denitrification process without generating any adverse chemistry or waste streams. This treatment was successful in rapidly reducing nitrate+nitrite-N levels to below discharge criteria, facilitating the resumption of permitted TSF discharge and demonstrating a sustainable, cost-effective strategy for managing mine water quality. This initiative marks a pioneering application of such a treatment in operational mines within Canada, underscoring the potential for wider adoption in industry.