The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News – June 23, 2023
Coeur Mining is carrying out a comprehensive exploration program to expand the high-grade silver-zinc-lead deposits at its Silvertip project in Northern British Columbia.
Click on image for larger Silvertip exploration target map.
With recent exploration indicating that the resource outlined at Silvertip may be just a portion of a much larger mineralized system, Coeur Mining Inc. is launching a comprehensive exploration program at this high-grade silver mine project in the northernmost reaches of British Columbia.
Going into 2023, Silvertip hosted 7.04 million tons of measured and indicated resources averaging 8.52 ounces per ton (60.1 million oz) silver, 9.68% (1.37 million lb) zinc, and 5.12% (722.2 million lb) lead; plus 1.87 million tons of inferred resource averaging 7.7 oz/t (14.4 million oz) silver, 10.9% (378.1 million lb) zinc, and 4.43% (166 million lb) lead.
While the amount of silver, zinc, and lead contained within the higher-confidence measured and indicated resource categories has roughly doubled over the past year, Coeur geologists have identified several areas for further significant expansion.
"The Silvertip team has made impressive progress on advancing the geologic understanding of this emerging world-class ore body, and the commencement of this focused drilling campaign over the next 18 months positions us to pursue our primary goal of growing overall resource tonnage," said Coeur Mining President and CEO Mitchell Krebs.
Building off the enhanced geological understanding of the larger system responsible for the high-grade carbonate replacement silver deposit at Silvertip, the coming 1.5-year exploration campaign has four primary objectives:
• Expand the resource by drilling known extensions to mineralization directly north and south of Silvertip.
• Test additional horizons to ascertain the full vertical extent of mineralized horizons through the stratigraphic column.
• Explore an immediately adjacent heat source to test for skarn and porphyry styles of mineralization.
• Test high-priority regional look-alike targets.
"We believe the resource base currently outlined at Silvertip represents a distal portion of a large mineralizing system and the detailed geological analysis and modelling completed during the first half of 2023 supports that thinking," said Coeur Mining Senior Vice President of Exploration Aoife McGrath. "The understanding gained through this process is allowing us to target exploration more concisely and continue to work to build value at this world-class project."
The carbonate replacement silver mineralization originally outlined at Silvertip is hosted in a single manto (flat-lying) horizon located at the top of the McDame Limestone package in contact with overlying sediments.
Since acquiring Silvertip in late 2017, Coeur has discovered several new, stacked manto horizons hosted at different elevations throughout the McDame Limestone.
Several mineralized chimneys have also been discovered within the McDame Limestone. Southern Silver Zone, the largest such chimney zone, accounts for roughly 50% of the inferred and 9% of the measured and indicated resources at Silvertip.
Coeur says multiple other chimney targets have been identified and are ready for drill testing during this new program.
In addition, silver-enriched mantos and chimneys in the McDame Limestone, favorable indications for mineralization have also been identified in the underlying dolostone, sandstone, and limestone units. This opens up more than 2,500 vertical meters of stratigraphy that is prospective for stacked, carbonate replacement deposits.
Testing this large vertical extent of stratigraphy is a key focus of the upcoming drill program.
Another primary target for drilling will be to continue building the resource base immediately adjacent to Silvertip located near existing underground development.
The main target for the resource extension drilling is a 2,000-meter corridor immediately south of the main Silvertip deposit through the Saddle and Tour Ridge zones. Coeur says 15 out of 16 scout holes drilled across this corridor over the previous three years have intersected mineralization. Silver mineralization has also been identified up to 1,000 meters north of the Silvertip resources, doubling the known mineralized strike length to more than 4,000 meters.
Alongside the known silver, lead, and zinc carbonate replacement style mineralization, the wider Silvertip property is prospective for porphyry and skarn mineralization.
A recently completed deep drill hole tested a circular, geophysical anomaly located to the southeast of Silvertip. This anomaly is interpreted to be a potential heat and fluid source for the Silvertip deposit. Coeur says this long hole drilled from underground cut higher temperature mineralogical assemblages and increased quantities of alteration and veining that are indicative of an intrusive porphyry or skarn source at depth. The hole, therefore, provided proof of concept, and additional exploration drilling is being designed to further test this target during the next 18-24 months.
Several other, similar circular geophysical anomalies are seen on the Silvertip land package. These are associated with similar structural features and geochemical signatures and are, therefore, look-alike targets to Silvertip.
Silvertip has also shown the potential as a source of critical metals beyond the silver, zinc, and lead the project is known for.
"Silvertip is one of the highest-grade undeveloped carbonate replacement deposits in the world, hosting large and growing resources of silver, zinc and lead – three minerals already playing key roles in the accelerating transition to a net-zero emissions global economy," said Krebs. "Located in British Columbia, recent drilling at Silvertip has also identified a suite of other key critical minerals that may further support the growing strategic value of this deposit for Canada and for Coeur as a key driver of future growth."
The company says it has engaged the Canadian government about including Silvertip in the Canadian Critical Minerals Strategy.
To fund its exploration for silver, zinc, lead, and other potential critical minerals, Coeur has arranged a roughly C$25 million (US$19 million) financing in Canada that will involve the issuance of 5.28 million flow-through shares.
Under a provision of Canada's Income Tax Act, flow-through financings allow companies to transfer expenses for mineral exploration in Canada to individual investors that purchase the flow-through shares. The flow-through investor, in turn, can apply his portion of the exploration expense to reduce or eliminate his Canadian tax liability.
This financing could go as high as approximately C$39 million (US$30 million) if all of the 3 million overallotment shares granted by Coeur are purchased.
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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