Colorado School of Mines thesis confirms that the germanium values in Alaska deposit have long been underreported.
In addition to hosting 6.3 billion pounds of copper and 88 million lb of cobalt critical to the energy transition, the Bornite deposit in Alaska’s Ambler Mining District may also be a significant source of the germanium essential to both clean energy and high-tech.
“Germanium is an important metal with numerous applications, particularly in the manufacture of semiconductor chips, fiber-optic systems, and high efficiency solar cells,” said Trilogy Metals President and CEO Tony Giardini.
Trilogy has been working with the Colorado School of Mines and U.S. Geological Survey to understand the germanium potential at Bornite, the second most advanced deposit of the Upper Kobuk Mineral Projects in Northwest Alaska.
The USGS first recognized copper mineralization at Bornite in the 1980s, and Trilogy has suspected that the values of this tech metal have been underrepresented since 2011.
The urgency to gain a better understanding of Bornite’s potential as a future source of germanium –alongside the copper and cobalt this deposit is known for – increased with China’s recently implemented state-controlled restrictions on germanium and gallium exports.
“Prices for the high-value metal have steadily climbed to approximately $2,750 per kilogram, a 35% increase from January 2020,” Giardini said. “We believe this trend will continue due to China’s recent export curb.”
“It is imperative that other sources of germanium are developed,” the Trilogy Metals CEO added.
Brief history of Bornite germanium
Bornite is a high-grade carbonate-hosted copper-cobalt deposit that was first explored by Kennecott Exploration during the 1960s and then came under NANA Regional Corp.’s ownership following the Alaska Native Claims Settlement Act in 1971.
Trilogy Metals founder and former CEO Rick Van Nieuwenhuyse forged a partnership with NANA in 2011 to merge the Native-owned lands that cover Bornite and adjacent public lands that host the world-class Arctic Mine project into the 427,690-acre Upper Kobuk Mineral Projects.
Under Ambler Metals LLC – a joint venture owned equally by Trilogy and South32 Ltd. to advance UKMP – roughly 9 billion lb of copper, 3.5 billion lb of zinc, 77 million lb of cobalt, and rich stores of gold and silver have been outlined at Arctic and Bornite, the two most advanced projects.
Recent work carried out by Trilogy, Colorado School of Mines, and USGS indicates the potential for germanium being added to the mix.
While Bornite has long been recognized for its germanium, the scope of this potential has never been reflected in the assays. The primary reason for this is the germanium compound found in the deposit is lost during a reaction with hydrochloric acid.
Recognizing that the germanium values were being underreported as far back as 2011, Trilogy had 50 core samples from four holes tested with preparation methods for germanium.
Highlights from this initial sampling include:
• 6.8 meters averaging 24.47% copper and 16 parts per million germanium in hole RC11-0183.
• 4.5 meters averaging 7.96% copper and 9 ppm germanium in hole RC11-0185.
• 17.6 meters averaging 12.45% copper and 30 ppm germanium in hole RC11-0187.
• 5.6 meters averaging 9.8% copper and 8 ppm germanium in hole RC11-0194.
These germanium values are significantly higher than the 1.15 ppm maximum germanium values from standard assays.
Trilogy also had ALS laboratory in Australia analyze samples collected from a pile of mineralization excavated from a shaft that Kennecott sunk into Bornite during the 1960s using an analytical method specialized to prevent the loss of the volatile germanium compound. This work has further confirmed that germanium is being lost in samples dissolved with acid.
A germanium thesis
As part of a Master of Science thesis at the Colorado School of Mines, Alexander Jones had 84 samples from five additional holes drilled at Bornite sampled for germanium. These samples, which were selected from core with high copper grades due to an association of copper sulfides and germanium previously recognized by USGS, contained as much as 125 ppm germanium.
Though these samples represent only a small part of the South Reef area of the Bornite deposit, Trilogy says the results clearly demonstrate that germanium is present at levels that are significantly higher than previously reported.
More importantly for potential future germanium byproduct recoveries at Bornite, the thesis work confirms a close association between the germanium sulfide mineral renierite and the copper minerals, which suggests the germanium will, at least partially, be recovered in the copper concentrate during flotation without special or additional processing.
“I would like to thank Alexander Jones for the research he did as part of his MSc thesis at the Colorado School of Mines on the distribution of germanium at the South Reef deposit, as well as his supervisor, Dr. Katharina Pfaff, Manager of the School’s Mineral and Material Characterization Facility, and Dr. Garth Graham of the USGS for their oversight and assistance in the collection and subsequent studies,” said Trilogy Metals Vice President of Exploration Richard Gosse. “The high standard of their analytical work has highlighted the importance of germanium at Bornite and we look forward to contributing to their new project to better understand the availability of critical mineral resources in the US.”
Rising germanium criticality
With its superior optic and semiconductive properties, germanium has numerous high-tech applications, including fiber optics, night vision devices, triple-layered solar panels, and transistors for classic and quantum computers.
While these uses and a relative scarcity has germanium high on the U.S. list of critical minerals, China’s controls on exports to “safeguard national security interests” has elevated this tech metal’s criticality.
Unlike many of the minerals deemed critical to the U.S., however, germanium is mined domestically – at Teck Resources Ltd.’s Red Dog Mine on NANA lands about 170 miles northwest of Bornite.
As operator of both the Red Dog and Trail Operations – a refinery in southern British Columbia that processes the concentrates from Red Dog and other zinc mines – Teck is the largest germanium producer in North America.
Due to germanium being recovered as a byproduct of zinc, coupled with Trail processing concentrates from other operations, the exact amount of germanium produced from Red Dog is unclear.
Despite the germanium recovered from Red Dog and a mine in Tennessee, the U.S. remains dependent on imports, predominantly from China, for more than 50% of its supply.
The recent sampling at Bornite, however, indicates that this world-class Northwest Alaska copper-cobalt deposit could offer a future domestic supply of germanium.
Ambler Metals will be providing the Colorado School of Mines’ Center to Advance the Science of Exploration to Reclamation in Mining with Bornite samples for further studies. Leveraging USGS funding, these studies will further investigate the occurrence, distribution, and recovery of germanium and other critical elements.
Including the work done by Jones, it appears only 140 samples have been correctly analyzed for germanium in the more than 70 years since the first hole was drilled at Bornite.
One of the objectives of the ongoing work at the Colorado School of Mines is to build upon the Bornite sample dataset.
“We are excited about our ongoing collaboration with the USGS and the Colorado School of Mines,” said Giardini.
Source: metal tech news
