Izok opening up the North

The challenge of further exploring and developing the Izok Lake, Hood River and Gondor massive sulphide properties in Canada’s far north appears to be off to a strong start.

Faced with the reality of declining reserves at many of its operations, Minnova (TSE) took a bold step last year when it acquired 100% of Izok and Hood River and 60% of Gondor from Falconbridge. It went on to form a strategic joint venture alliance with Metall Mining (TSE), an international major with considerable Arctic experience.

More recently, Metall agreed to pay $136.6 million to acquire a 50.4% interest in Minnova, a transaction which will give it a 70% direct and indirect interest in Izok Lake as well as exposure to a land package considered highly prospective for new discoveries.

The companies are now carrying out a full detailed engineering and environmental feasibility study for the Izok deposit about 70 km west of Echo Bay’s Lupin gold mine, and about 260 km south of Coppermine on Coronation Gulf. Access is currently by air from Yellowknife.

Activity began in February when the all-season camp, fuel and drilling equipment was brought in over winter road by Echo Bay, and set up at the Ham Lake site. An 800-metre gravel airstrip was also built, and is now being extended to allow for larger aircraft.

More than 18,000 metres of drilling in 122 holes was also completed between late March and July. Frank Balint, Minnova’s exploration manager for Central Canada, and Ian Morrison, senior project geologist, said the bulk of the drilling (about 90 holes) was aimed at defining and increasing confidence in Izok reserves through a 30-metre spaced definition program.

“Results were encouraging,” Balint said during a recent site visit, adding that the drilling “confirmed Minnova’s optimistic estimate of reserves, along with an increased level of confidence in the grade, continuity and overall tonnage of the deposit.”

A new reserve calculation is in progress and should be released this fall. Before this year’s drilling began, Minnova calculated a geological reserve for Izok totalling 13.4 million tonnes grading 3.2% copper, 14.4% zinc, 1.3% lead and 74.1 grams silver per tonne, with 12 million tonnes of this classed as probable and possible.

This calculation was based on recent interpretative work and on work carried out in the 1970s by Texasgulf, the first to identify felsic volcanics in the region as being prospective for volcanogenic massive sulphide (VMS) deposits. The first discovery, which outcrops, was made at Hood River. The subsequent discovery of high-grade massive sulphide boulders around Izok Lake in 1974 led to a drilling program in 1975 which intersected 6.2 metres of massive sulphides grading 0.85% copper, 15.2% zinc, 1.5% lead and 74 grams silver in the first hole. Subsequent drilling in 1975 and 1976 totalled more than 15,000 metres in 146 holes.

The deposit for the most part underlies Izok Lake (which is so shallow it’s possible to see gossaneous staining under the water from the air) and is amenable to open pit mining at an estimated strip ratio of 3-to-1. Essentially flat-lying with two cup-shaped bulges, the deposit is hosted within and near the top of a thick sequence of felsic volcanic rocks and overlain by a succession of volcanoclastics, iron formation, mafic flows and turbidite sediments. (Metamorphism is of amphibolite grade.) The deposit features a strong VMS hydrothermal envelope of sericite-biotite alteration, lesser chlorite-cordierite-anthophyllite, aluminosilicates and silicification of the host rocks.

Mineralogy is predominantly coarse-grained sphalerite, chalcopyrite, galena, pyrrhotite and pyrite. There are two main lenses. The northwest zone measures 200 metres by 280 metres by 22 metres at a depth of 30-130 metres. And the Central zone, a trough-shaped composite lens, measures 450 metres in length by 110 metres in width; depths range from 0-160 metres, with copper-rich stringer sulphide mineralization developed under the west end of this lens. “We will have a starter pit with low stripping to provide cash flow in the early mine life,” Balint said.

Minnova’s program was also aimed at exploring for and defining underground reserves accessible from the proposed open pit. This goal was realized by the discovery of a new deposit, Inukskuk, the result of testing a deep electromagnetic anomaly on trend with the Izok deposit.

“Pulse EM (surface and borehole) is the only kind of geophysics we do at present,” Morrison said. “It worked well at Winston Lake (Minnova’s zinc-copper mine in northwestern Ontario) and it works well here. We hit the conductor with our first hole at Inukshuk.”

The new deposit, still open down plunge, is a dipping elongate lens defined over a strike length of more than 300 metres. It has a width of 150 metres, average thickness of 10 metres, and ranges in depth from 60-400 metres. A reserve of 2 million tonnes grading 2% copper and 8% zinc is inferred based on seven widely spaced holes.

This year’s exploration effort is also aimed at testing targets in the immediate Izok area generated from existing and new data. Continued exploration features an integration of geological mapping, lithogeochemistry and deep EM on the Izok property and adjoining claims. The objective is to identify new VMS target areas as defined by focused hydrothermal activity, favorable volcanic stratigraphy and structures and associated conductors. “Minnova was looking for people with northern experience for this field work,” quipped one geologist. “What this really means is you’ve experienced the weather and bugs, and you’re willing to come back and experience it again.”

Exploration is also ongoing at the Hood property, 50 km north of Izok, where previous work outlined massive sulphide mineralization in three separate pods. The richest so far, zone 10, contains a preliminary reserve of 1.2 million tonnes grading 4.1% copper, 4.4% zinc, 27 grams silver and 0.7 grams gold per tonne. But the zone is steeply dipping, and considered an underground resource.

“The deposits at Hood are too small to stand alone,” Morrison said, adding that ongoing work will include some deeper, wide-spaced drilling aimed at “finding an elephant.”

Work hasn’t started yet at Gondor, 60 km east of Izok, which has 7.3 million tonnes grading 0.2% copper, 4.8% zinc, and 46 grams silver. But early stage work is under way on other claims elsewhere in the Point Lake formation, a belt of mafic to felsic metavolcanics belonging to the Yellowknife Supergroup of the Archean-aged Slave structural province.

“We have a lot to explore,” Balint said, pointing to several gossans on the immediate horizon which remain untested. “But our main priority is to advance Izok to feasibility.”

This will involve metallurgical test work, environmental and social impact studies, and mine transportation engineering studies. A fly-in, fly-out operation is envisioned that would initially mine (open pit) and mill 3,000 tonnes per day (followed by underground production). About 400,000 tonnes of concentrate would be stored on site, and then transported to the Arctic coast by truck by winter road. The concentrate would be stored at a port for shipment during a summer season.

Minnova and Metall estimate it will cost about $350 million to build a mine, mill, winter road and port for Izok Lake, already considered “on the borderline” of being economically viable.

But industry sources expect that other mining companies active in the region, and the federal and territorial governments, may contribute to some of the infrastructure-related costs, in particular to building a new port at Coronation Gulf. A study is already in progress to examine this proposal which will go a long way to make the goal of building new mines in the north a reality.