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Early Silvertip drill results bode well for north BC mine restart North of 60 Mining News – June 18, 2021
The Southern Silver zone could become a significant source of reserves for Coeur's planned reopening of the Silvertip Mine.
After setting a company record for exploration spending during 2020, Coeur Mining Inc. is on pace to set the bar even higher this year.
"We are carrying out our most active exploration campaign in Coeur's history with up to 22 drill rigs deployed across six sites, with positive results rolling in on a regular basis," said Coeur Mining Vice President of Exploration Hans Rasmussen.
Through the first four months of 2021, these rigs completed roughly 103,750 meters of drilling, a 66% increase compared to the same period in 2020.
Coeur anticipates investing US$68 million into exploration this year, which is more than 30% higher than the US$50.6 million exploration investment last year.
The Chicago-based company's record-setting 2021 exploration includes extensive drilling at Silvertip, a Northern British Columbia silver-zinc-lead mine that was idled down early in 2020 to accelerate investment into exploration and mill expansion at the new mine.
By the end of April, Coeur had already completed roughly 31,825 meters of drilling this year at Silvertip, more than six times the 5,100 meters drilled at this Northern BC silver project during the first four months of 2020.
Rasmussen says assay results from this early 2021 drilling demonstrate the significant upside potential Silvertip has to offer.
Southern Silver discovery
Building the late-2020 exploration at Silvertip, Coeur began this year's exploration at the high-grade silver project with five surface drills and one underground core rig focusing on resource expansion, as well as infill drilling on select areas of the deposit to convert resources to reserves.
Going into 2020, Silvertip hosted 1.8 million tons of proven and probable reserves averaging 8.11 oz/t (14.64 million oz) silver, 8.2% (259.5 million pounds) zinc, and 5.4% (193.2 million lb) lead.
In addition to reserves, the property hosts 2.3 million tons of measured and indicated resources averaging 7.44 oz/t (17.4 million oz) silver, 9.4% (442.1 million lb) zinc and 4.6% (216.5 million lb) lead; and 1.5 tons of inferred resource averaging 8.3 oz/t (12 million oz) silver, 10.6% (308.7 million lb) zinc and 5% (143.9 million lb) lead.
Coeur completed an underground development drift late last year to access 65 Zone, which is located south-southeast of the original Silver Creek mine area. Drilling from this drift quickly led to the discovery of the Southern Silver zone, which has a different geometry and completely envelops the historic 65 Zone.
Southern Silver represents a new style of mineralization at Silvertip – a vertically oriented and high-grade breccia-type mineralization, in contrast to the horizontal manto-style mineralization in the historic 65 Zone.
Highlights from this year's drilling at the Southern Silver discovery include:
• 6.4 meters averaging 14.4 oz/t (493.7 grams per metric ton) silver, 23.7% zinc, and 8.7% lead in hole 65Z21-485-360-002.
• 5.8 meters averaging 6.5 oz/t (222.9 g/t) silver, 21% zinc, and 2.8% lead in 65Z21-485-360-020.
• 6.4 meters averaging 18.4 oz/t (630.9 g/t) silver, 14.8% zinc, and 10.5% lead in 65Z21-485-360-026.
• 5.8 meters averaging 7.8 oz/t (267.4 g/t) silver, 21.3% zinc, and 3.9% lead in 65Z21-485-DDS1-003.
Southern Silver could become a significant source of reserves for Coeur's planned reopening of the Silvertip Mine.
"Successful results like these continue to reinforce Silvertip's status as one of the world's highest-grade silver-zinc-lead deposits and provide valuable data points as we work towards our goal of ending the year with a compelling business case to justify moving forward with an expansion and restart," said Rasmussen.
Intercepts from the deepest holes at Southern Silver suggest this zone continues to depths beyond the current drilling, which has been outlined for roughly 300 vertical meters so far.
The company believes that Southern Silver may be a vertical feeder structure and other, similar structures may exist and may be discovered with horizontal holes the company is drilling from underground.
Based on encouraging initial results, Coeur mobilized a second underground rig, as well as a surface core rig, to expand the Southern Silver zone.
The Silvertip exploration team is also re-evaluating historical core logs and photos with the goal of identifying similar karst-controlled structures and testing for vertically oriented mineralization in other parts of the mine.
Three-dimensional modeling of all the geological and geophysical data suggests that the Southern Silver Zone connects the Silver Creek Zone with the Discovery South Zone, representing the potential for significant resource growth.
To assist in new drill targeting and gain a better understanding of the regional exploration potential around Silvertip, an airborne Sky Time-Domain Electromagnetic (SkyTEM) geophysical survey, which has the ability to map resistivity features up to around 300 meters below the surface, was completed in March. Based on a preliminary review of the SkyTEM data, there appear to be several features that have the potential to extend the Discovery, Camp Creek, Tour Ridge, and Southern Silver zones, as well as the Tiger Terrace target area.
For the remainder of 2021, Coeur expects exploration at Silvertip to focus on:
• Underground and surface drilling to test the southern and northern extensions of Southern Silver.
• Expand the multiple stacked massive sulfide horizons at the Discovery North and East Zones.
• Test extensions of the Camp Creek zone to the north and south.
• Drill the first holes at Tiger Terrace where coincident geochemical and geophysical anomalies, as well as the geologic setting, suggest the presence of Silvertip-style mineralization.
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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