The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News - August 13, 2024
This chunk of high-grade copper found lying on the surface at Storm indicates the potential of using ore sorting to produce high-quality direct shipping ore concentrates at the Nunavut project.
Storm copper mineralisation being processed by a Steinert XRT ore-sorter in Perth, Australia.
This flowsheet shows a typical mid-range case for using XRT ore sorting and inline pressure jig gravity separation to produce direct shipping ore copper concentrates from the Chinook deposit at Storm.
Recent testing has demonstrated that a simple and inexpensive two-step process could elevate the high-grade copper mineralization that American West Metals Ltd. has outlined in near-surface deposits at its Storm project in Nunavut into a high-quality direct shipping ore (DSO) ready for market.
"The program has produced commercial grade DSO products from typical copper ores through an uncomplicated and low-cost process," said American West Metals Managing Director Dave O'Neill. "This is game changing for the Storm project and world-leading in terms of copper processing innovation and performance."
What is considered typical at Storm is deemed high-grade by global copper project standards.
According to a calculation completed in January, four deposits within a roughly 10-square-kilometer (3.9 square miles) area of the Storm property host 17.5 million metric tons of Australian Joint Ore Reserves Committee- (JORC) compliant indicated and inferred resources averaging 1.17% (452 million lb) copper and 3.38 grams per metric ton (1.9 million oz) silver.
This is roughly double the approximately 0.6% average copper ore grade being mined globally.
Metallurgical testing has shown that a straightforward and inexpensive process with a small environmental footprint could upgrade copper mineralization at Storm to a direct shipping ore containing roughly 20% copper.
"The process of generating DSO at Storm is amazingly simple and highlights our company's focus on generating ESG sensitive and low capital development solutions," said O'Neill. "Storm Copper now stands out as one of the very few, and highest-grade DSO copper opportunities globally."
Storm copper mineralisation being processed by a Steinert XRT ore-sorter in Perth, Australia.
The amazingly simple and low-cost DSO solution involves the use of an X-ray transmission (XRT) ore sorter and an inline pressure jig.
After mining and crushing, any Storm Copper ore that is over 0.4 inches (10 millimeters) would be sent to the ore sorter, where an XRT sensor would identify and reject any unmineralized rock. The ore that is smaller than 0.4 inches would be run through the jig, which would use gravity separation to produce direct shipping ore.
Three international consulting firms – ALS Metallurgy, Sacre-Davey, and Nexus Bonum – utilized samples from the Cyclone and Chinook deposits at Storm for the study. After initial testing with ore sorting alone, Nexus brought in the jig circuit to capture value from the undersized ore.
The study found that a 1.5-million-metric-ton-per-year plant with the ore sorting and jig circuits processing 1.2% to 1.5% copper ore from Cyclone could produce 10,000 to 14,000 metric tons of copper per year in a concentrate averaging 16 to 22% copper. The same circuits processing 1.5% copper ore from Chinook could produce 15,000 to 16,000 metric tons of copper per year in a concentrate averaging 16 to 22% copper.
This flowsheet shows a typical mid-range case for using XRT ore sorting and inline pressure jig gravity separation to produce direct shipping ore copper concentrates from the Chinook deposit at Storm.
The cost of the equipment for the two-circuit direct shipping ore plant is estimated to be between $18 million and $20 million, and the cost to process the ore is calculated to be $4 per metric ton.
In addition to low capital and operating costs, the straightforward design, small environmental footprint, and lack of the need for a floatation plant and associated tailings storage facility will reduce the risks and timeline associated with permitting and developing a DSO mine at Storm.
"This proof-of-concept processing option for Storm significantly derisks the project from a development, funding and permitting perspective," said O'Neill.
The high-grade copper resources outlined so far at Storm are found in deposits that are at or near the surface, and a roughly 20,000-meter drill program being conducted this summer is focused largely on upgrading and expanding upon these deposits.
While the first batch of assays from the 2024 drill program is pending, American West reported that the drills have encountered thick intervals of copper mineralization in and around the known deposits and new high-grade copper zones – indicating the likelihood that more potential direct shipping ore will be available when a new resource is calculated for Storm.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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