US Environment Protection Agency (USEPA) regulations require mining operations to remediate their waste streams prior to environmental discharge. Wastewater streams from gold mine operations can be particularly toxic due to the potential for cyanide contamination and the concentration of metals contained in the wastewater effluent.
This paper reviews the challenges and success of installing and operating an ozone oxidation system for wastewater remediation at a gold mine located in a remote region of Alaska. Cyanide leaching, carbon in pulp (CIP) and electrowinning processes utilized to extract gold from the mine’s ore are reviewed. The remediation of metals and arsenic from the mine’s wastewater dewatering process, utilizing ozone oxidation chemistry and ultrafiltration prior to reinjection into a local aquifer, are discussed in detail. The unique equipment designs to ensure reliability of a remote and isolated ozone system are included in this review.