Over its lifetime, the mine would produce an average of 95.9 million lb. of copper, 99,900 gold oz., and 3 million lb. of molybdenum a year (155.9 million lb. of copper-equivalent) a year at all-in sustaining costs of C$2.14 per lb. of copper-equivalent.
Based on an initial capital cost estimate of C$1.4 billion and C$197 million required in sustaining capital, the after-tax net present value estimate comes in at C$1.1 billion, based on an 8% discount rate, with a 19% internal rate of return. The study assumed metal prices of $3.25 per lb. copper, $1,650 per oz. gold and $10 per lb. molybdenum.
“The concentrate planned to be produced by the North Island project is anticipated to be a premium product which would be highly attractive to global smelters. Furthermore, the significant gold production is anticipated to provide several options for lower cost capital financings,” Sam Lee, Northisle’s president and CEO, said in a release.
Opportunities to improve the project economics include exploration – an initial drill program will focus on the Red Dog, Pemberton Hills and Hushamu areas. Additional upside areas include potential for sales of a pyrite concentrate, use of a historical pit for tailings storage, trolley assisted haulage options and metallurgical optimization, among others.
With the PEA release, Northisle now plans to advance North Island towards a pre-feasibility study.
Indicated resources across Hushamu and Red Dog total 527.3 million tonnes grading 0.2% copper, 0.24 g/t gold and 0.008% molybdenum (0.41% copper-equivalent) with an additional 417.3 million inferred tonnes at 0.15% copper, 0.18 g/t gold and 0.006% molybdenum (0.31% copper-equivalent).
North Island sits within a 331.5-sq. km block that covers a 50-km stretch of ground.
In an additional release, Northisle announced that it had regained 100% control of the Pemberton Hills target at North Island. This area had previously been optioned to Freeport-McMoRan (NYSE: FCX). The latter provided Northisle with a notice of termination of their option.
According to Jack McClintock, Northisle’s VP of exploration, prior exploration over this target area defined a 1.5 km by 1 km target, within a 3.5 km by 1.5 km lithocap (subsurface alteration area) for an anticipated buried copper-gold porphyry system. The target includes a coincident geophysical anomaly as well as trace element, clay, geological and structural vectors.
The company has allocated a C$1 million, three-hole budget to test the target, which is expected to start around mid-March.
(This article first appeared in the Canadian Mining Journal)
