Teck has partnered with Aurubis, Europe’s largest refined copper producer, to advance the application of CESL Copper-Arsenic (Cu-As) Technology for high arsenic bearing copper resources. Together, we provide strong technical capabilities and extensive industry experience in the copper business.
Overall, the policies and guidelines of both Teck and Aurubis fully support the strengthening of sustainable development by setting new environmental standards in complex ore refinement. The key element for this basis is the introduction of a novel, integrated, low-emission mine-to-metal process based on the commercial-ready CESL Cu-Au Technology.
The CESL Cu-As Process has achieved greater than 99% deportment of arsenic to leach residues (the by-product of the metallurgical process). Arsenic components in the residue have been identified, with the use of advanced mineralogical methods, as basic ferric arsenate (BFAS) and scorodite – both of which are considered the most stable forms for arsenic fixation. Furthermore, air quality monitoring during pilot operations confirmed concentrations well below the government occupational exposure levels.
Short- and long-term testing was conducted to assess the stability of arsenic in residues that were generated in continuous pilot plant trials. Short-term testing was conducted on 59 pilot samples containing arsenic up to 9.7% using the Environmental Protection Agency’s (EPA) standard hazardous material characterization procedure (Toxicity Characteristic Leaching Procedure, TCLP). The testing consistently demonstrated that the residue was non-hazardous, with leached arsenic more than an order of magnitude below the EPA classification limit.
To confirm long-term stability, a more rigorous testing program was developed. This ongoing test program has demonstrated excellent residue stability, with arsenic concentrations well below the 5 milligrams per litre EPA limit after over 800 days plus of testing.
Over 20 different arsenic-bearing concentrate samples have been tested since 2010. This has included over 10-months of pilot plant operations to verify the flowsheet using fully-integrated continuous operations. Pilot plant operation result highlights include: