Mining News: Excellent copper, zinc recoveries in clean concentrates from Arctic
Trilogy Metals Inc. April 19 said recently completed metallurgical testing demonstrates that excellent metals recoveries and clean copper and zinc concentrates can be generated from the copper-lead-zinc-gold-silver ores at Arctic, a volcanogenic massive sulfide deposit at the Upper Kobuk Mineral Projects in Northwest Alaska. During 2016, Trilogy completed four holes targeting mineralized material that is planned to be mined during the first seven years of production at Arctic. A 600-kilogram composite sample of this material was used in bench scale testing to confirm the performance of the previously defined flotation process; as well, a large volume of the sample was processed in a pilot plant to provide sufficient volumes of a copper-lead bulk concentrate to complete detailed copper and lead separation test work. Copper recoveries averaged 91.7 percent and formed a concentrate averaging 28.7 percent copper metal. Zinc recoveries averaged 87.8 percent and formed a concentrate averaging 60 percent zinc metal. The revenue stream in a 2013 preliminary economic assessment for Arctic showed that copper produced 60 percent of the revenue stream, with zinc contributing 21 percent, silver at 9 percent and gold at 6 percent. Lead was the least valuable of the metals. The bulk of the precious metals report to the zinc concentrate and further testing is being carried out to determine optimal recoveries for lead, gold and silver. Neither the zinc nor the copper concentrates contain any significant deleterious penalty metals and are considered excellent quality by world standards. "We are very pleased with the results of this metallurgical test work program at Arctic. Recoveries and concentrate grades for our two principle metals – copper and zinc are excellent. We are currently conducting additional test work to determine the optimal recoveries of our three other metals – lead, gold and silver, and will report on that work in due course,” said Trilogy Metals President and CEO Rick Van Nieuwenhuyse. In addition to the metallurgical work, the company reported that the in-pit geotechnical and hydrology studies for Arctic are now completed to a level that they can be incorporated into a prefeasibility study, which is expected to be finalized in the first quarter of 2018. Roughly US$17 million has been budgeted for the 2017 program at Arctic. This work includes US$7.1 million invested into collecting the final information for the Arctic prefeasibility study and US$10 million, funded by South32 Ltd., for exploration at Bornite, a high-grade copper deposit about 16 miles south of Arctic. “The PFS will demonstrate the true value of the high-grade Arctic deposit which we expect will be the first in a series of potential mines in the Ambler mining district,” said Van Nieuwenhuyse. “With the recent announcement that the BLM has initiated the permitting process on the AMDIAP (Ambler Mining District Industrial Access Road); our recently announced option agreement with South32 whereby they will fund a $10 million program at our Bornite deposit in 2017; and an upswing in demand for copper and zinc, the company is well positioned to add value for shareholders by advancing development of the Ambler mining district."