The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Copper output up; East Ridge discovery continues to impress North of 60 Mining News – July 23, 2021
Drilling at Red Chris continues to encounter impressive gold-copper grades at East Ridge, a zone that indicates the resource expansion potential at the Northern BC mine.
Newcrest Mining Ltd. and Imperial Metals Corp. July 22 reported that the Red Chris mine in Northern British Columbia produced 17.6 million pounds copper and 15,451 ounces gold during the second quarter, compared to 15.9 million lb of copper and 15,850 oz of gold during the first quarter.
This nearly 11% increase in copper and nearly par gold production during the second quarter is the result of increased mill throughput and recoveries that was offset by lower head grades of 0.40% copper and 0.35 grams per metric ton gold, compared to 0.43% copper and 0.42g/t gold in the first three months of the year.
Newcrest, which owns a 70% joint venture interest in Red Chris, announced plans earlier this year to invest C$12 million to begin construction of a box cut for an underground decline at Red Chris. The surface work and related infrastructure being established by this work is in preparation for the underground development needed for more detailed exploration and eventually mining.
A prefeasibility study slated for completion in September will provide details of a planned block cave mining operation at Red Chris.
Block cave mining is a bulk tonnage underground mining technique that involves starting at the bottom of the orebody and allowing the deposit to progressively collapse under its own weight.
Newcrest has been successful with this technique at Cadia, an Australian mine similar to Red Chris.
The roughly 3,500-meter underground exploration decline being developed at the Red Chris will allow for more detailed drilling, as well as the potential of mining a pod of high-grade copper-gold mineralization identified in the East Zone prior to much larger block cave operation at Red Chris.
Imperial Metals, which owns the remaining 30% interest in the copper-gold mine, says mining this particularly high-grade section of the East Zone prior to the block cave mining may increase initial cash flow and help fund the development of block caving operations.
The Red Chris partners report that the portal site excavation has been completed and the exploration decline has been advanced 21 meters as of July 14.
As crews drive the exploration decline, drilling continues to expand higher-grade mineralization at East Ridge, a discovery made earlier this year about 300 meters east of the East Zone.
"Our East Ridge discovery continues to impress, with drilling during the quarter returning the highest-grade intercept reported in this zone," said Newcrest Mining CEO Sandeep Biswas. "Drilling at East Ridge has extended the higher-grade mineralization across the eastern end of the porphyry corridor, which further highlights the potential for resource growth over time."
The intercept mentioned by Biswas came in hole RC700, which cut 366 meters averaging 1.1g/t gold and 0.93% copper from a depth of 738 meters, including 146 meters averaging 2.1g/t gold and 1.6% copper from 780 meters
"This intercept is similar to those encountered in the high-grade pods in the East Zone and shows that this eastern extension of mineralization at Red Chris has the potential to contain high-grade pods similar to those in the East Zone," said Imperial Metals President Brian Kynoch.
Hole RC700 was drilled 100 meters above RC688, a previously reported hole that cut 344 meters averaging 0.7 g/t gold and 0.75% copper from a depth of 776 meters, including 170 meters averaging 1.1 g/t gold and 1.1% copper from 892 meters.
Newcrest and Imperial say the discovery of such wide zones of high-grade mineralization illustrate the potential for the East Ridge to become an important new development area.
During the second quarter there were up to eight drill rigs in operation, completing 26 holes for a total of about 30,055 meters were drilled. All the holes, except six geotechnical drill holes, cut mineralization.
Since Newcrest became a JV partner in Red Chris toward the end of 2019, 166,686 meters of drilling has been completed in 137 holes at this Northern BC project.
Drilling is ongoing at East Ridge to further define the extent and continuity of this zone that remains open in all directions.
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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