The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Mining Explorers 2019 – Published Nov. 1, 2019
An aerial view of Coeur Mining's Silvertip Mine in the far north reaches of British Columbia.
Coeur's Kensington gold mine in Southeast Alaska.
Coeur Mining Inc. entered 2019 with more silver reserves at higher grades, thanks to a maiden reserve calculation for Silvertip, a northern British Columbia silver mine the company acquired in 2017.
While this newly built mine came with a rich resource base, a technical report and mine plan to elevate the high-grade silver resources to reserves had yet to be completed.
With the information gleaned from a rigorous drill program, by the end of 2018 Coeur had converted some 58 percent of the resources that came with Silvertip into enough reserves to support the mine for about 4.5 years.
According to this maiden reserve calculation, Silvertip hosts 1.6 million metric tons of reserves averaging 289 grams per metric ton (14.98 million oz) silver, 8.2 percent (292.71 million pounds) zinc and 5.6 percent (198.66 million lb) lead.
This is enough ore to boost Coeur's silver-equivalent reserves by 14 percent, while also boosting its company-wide silver reserve grade by 16 percent, as the silver reserve grade at Silvertip going into 2019 was 15 times higher than the combined silver reserves grades of the Chicago-based miner's other projects.
To expand Silvertip resources and reserves, Coeur will focus on drilling five near-mine zones – Discovery, Discovery North, Central, Silver Creek and 65.
Discovery zone is the primary target this year.
Highlights from Discovery zone drilling through mid-year include 7.9 meters of 428 g/t silver, 19.1 percent zinc and 8.1 percent lead in DSC19-Pad4-002; 7.9 meters of 153 g/t silver, 12.6 percent zinc and 3.1 percent lead in DSC19-Pad4-004; and 4.5 meters of 483 g/t silver, 16.5 percent zinc and 10.6 percent lead in DSC19-Pad1-003.
Given its success at Discovery through mid-year, the remainder of the 2019 Silvertip exploration drilling is focused on expanding the resource there to the north, east and south.
The company also invested in Alianza Minerals Ltd., a junior exploring the Tim silver property in southern Yukon.
Situated just 12 kilometers (7.5 miles) north of Silvertip, Tim is an early staged exploration property with similar high-grade silver-lead-zinc mineralization.
Historical chip sampling from a trench cut across a zone of carbonate replacement mineralization at Tim returned 352 g/t silver and 9.12 percent lead across four meters. Similar mineralization was also reported in adjacent trenches 180 and 250 meters on either side of the central trench.
Under a June agreement with Alianza, Coeur can earn a 51 percent interest in Tim by funding C$3.5 million in exploration over five years and making staged cash payments totaling C$275,000. Coeur can then elect to complete an option to earn 80 percent in the property by funding a positive feasibility study in the following three years and making annual payments of C$100,000.
At Kensington, reserve tonnages going into 2019 shrunk slightly when compared to a year earlier. However, thanks to higher grade reserves from the Jualin deposit, this lower quantity of ore contains more gold.
Going into 2019, Kensington has 2.59 million tons of proven and probable reserves averaging 6.6 g/t (552,000 oz) gold, compared to 2.67 million tons of proven and probable reserves averaging 6.1 g/t (520,000 oz) gold a year earlier.
This ore is contained in two historic mine areas that date back to the dawn of the 20th century –Kensington and Jualin.
The roughly 9 percent increase in reserve grade at this Southeast Alaska operation is largely attributed to upgrading portions of the resources in the Jualin deposit to reserves.
The maiden reserve estimate for Jualin, reported by Coeur last year, outlined 157,600 tons of ore averaging 14.6 g/t (74,100 oz) gold.
Supplementing mill feed with this higher grade ore is expected to increase Kensington gold output over the coming years.
The company anticipates mining 100 tons per day from Jualin in 2019 and more than 180 tons per day in 2020.
This year's exploration drilling at the Southeast Alaska operation focused on the Kensington Mine side of the property.
During the second quarter, Coeur had three underground core drill rigs focused primarily on resource expansion and infill drilling at Lower Raven and Elmira zones.
The company also had one surface rig that began drilling in late June on the Comet Vein, which lies directly above the Kensington Mine access tunnel.
Coeur uses a success-based strategy when it comes to allotting exploration budgets – adjusting the budget to focus on projects within its portfolio that are doing the best job of adding resources and reserves.
At mid-2019, Kensington and Silvertip were at the top of Coeur's exploration list.
"We ... continued to invest in our success-based exploration program, with encouraging near-mine resource expansion drill results at Kensington and Silvertip," Coeur Mining President and CEO Mitchell Krebs said in August.
Coeur Mining also holds a 9.6 percent stake in Rockhaven Resources Ltd., a junior exploring the Klaza gold project in southern Yukon. Klaza currently hosts 4.46 metric tons of indicated resource averaging 4.8 g/t (686,000 oz) gold and 98 g/t (14.1 million oz) silver; and 5.71 million metric tons of inferred resource averaging 2.8 g/t (507,000 oz) gold and 76 g/t (13.9 million oz) silver.
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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