Red Chris resources set the stage for PFS
Newcrest will now evaluate block cave mining at BC project North of 60 Mining News – March 31, 2021
Last updated 4/23/2021 at 6:07am
The Red Chris Mine in Northern British Columbia now hosts 13 million ounces of gold and 3.7 million metric tons (8.16 billion pounds) of copper, according to a new resource calculated for Newcrest Mining Ltd.
This marks the first resource calculation for Red Chris since Newcrest acquired a 70% ownership of the mine from Imperial Metals Corp. in August of 2019. Since gaining operational ownership, Newcrest has completed 109,177 meters of drilling in 92 holes at Red Chris.
According to the new Australian Joint Ore Reserves Committee- (JORC) compliant calculation, Red Chris hosts 980 million metric tons of measured and indicated resource averaging 0.41 grams per metric ton (13 million oz) gold and 0.38% (3.7 million metric tons) copper.
This includes 310 million metric tons of open pit mineable measured and indicated resource averaging 0.28 g/t (2.7 million oz) gold and 0.34% (1 million metric tons) copper; and 670 million metric tons of underground measured and indicated resource averaging 0.46 g/t (10 million oz) gold and 0.4% (2.7 million metric tons) copper.
In addition, Red Chris hosts 190 million metric tons of inferred resource averaging 0.31 g/t (1.9 million oz) gold and 0.3% (570,000 metric tons) copper. Roughly 95% of the inferred resource is considered underground mineable.
This initial JORC-compliant resource will form the foundation for a prefeasibility study that will provide a first look at block cave mining 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 announcement of our initial mineral resource estimate marks another milestone in our transformation of Red Chris," said Newcrest Mining CEO Sandeep Biswas. "We remain on track to release the findings of our block cave Pre-Feasibility Study by the end of September 2021 and continue to evaluate a number of early mining options which could enable an acceleration of cash flows prior to the development of a block cave."
One opportunity for accelerating cash flow from Red Chris is mining high-grade pods identified there with more conventional underground methods ahead of block caving.
Imperial Metals, which retains a 30% interest in the Red Chris joint venture, first tapped a high-grade pod in the East Zone with a 2009 hole that cut 432.5 meters of 2% copper and 3.8 g/t gold.
Newcrest's 2020 drilling cut additional wide sections with impressive grades at East Zone. Hole RC634 in particular demonstrates the high-grade pods within wide sections of porphyry mineralization at East Zone. This hole cut 532 meters averaging 1.3 g/t gold and 0.82% copper, which is more than double the average resource grade, including 166 meters averaging 3 g/t gold and 1.5% copper.
In February, Newcrest announced a C$12 million budget to begin construction on the box cut for the 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.
"The commencement of construction of the box cut is a significant milestone in the objective of having a block cave in operation at Red Chris in the next five to six years," said Biswas.
And the underground development could set the stage for mining high-grade zones in the interim.
Considering the recent drilling success, there will likely be more high-grade pods to mine ahead of block caving.
The first four holes of the 2021 drilling at Red Chris, reported by Newcrest in early March, all encountered significant copper-gold mineralization, including an important new discovery dubbed East Ridge.
Newcrest's first hole at East Ridge, RC678, cut 198 meters averaging 0.89 g/t gold and 0.83% copper from a depth of 800 meters, including 76 meters averaging 1.8 g/t gold and 1.5% copper from 908 meters.
The company says the style of mineralization and grade is similar to that seen in the high-grade pods at East Zone, which lies about 300 meters to the west.
"Drilling to determine the significance of this new zone is underway, with the results from this initial intercept highlighting the potential for additional discoveries at Red Chris," Biswas said.
In addition to the exciting East Ridge discovery, Newcrest and Imperial report that drilling at the East and Main zones continue to confirm the potential to expand higher-grade zones of mineralization at Red Chris, including south of the South Border Fault, which was previously considered the southern edge of the Main and East zone mineralization.
Newcrest and Imperial previously announced plans to complete roughly 50,000 meters of exploration drilling at Red Chris this year.
CORRECTION: This article was updated on April 23, 2021 to correctly state the pounds of copper in measured and indicated resources at 8.16 billion lb. The copper tonnage in the previous version was correct but the conversion to pounds was inaccurate.