Finding the Next Mines
Twenty-five years of largely unfocused exploration programs have left Noranda with uncomfortably small mine reserves. Recent corporate restructuring has resulted in a much clearer vision, according to Mike Knuckey, executive vice-president of exploration and project development.
The goal now is to find mines that will produce up to 500,000 tonnes of both copper and zinc per year, backed by at least 15 years of ore reserves. “What we really need is another two Antaminas,” says Knuckey; the polymetallic Peruvian mine development has 494 million tonnes of reserves.
What are the odds of the company finding them? “In terms of Canadian companies we have by far the largest base metal exploration budget,” says Knuckey. Noranda alone has maintained an exploration staff of 110, with a budget of $50-55 million in each of the last three years. Including Falconbridge Ltd. that budget rises to $80 million, which is 8-10% of what is spent on base metal exploration in the world.
Noranda is actively drilling in the Bathurst and Matagami areas to support its infrastructures there. The high-grade Lady Loretta property in Australia is another major program: “It could produce 100,000 tonnes of zinc per year, but that’s hypothetical as it’s still at the option stage,” says Knuckey. (A feasibility study is in progress.) Other programs are found in the accompanying table.
The company is on the forefront of tool development. The mandate of the research and technical innovation, exploration team is to use the best exploration tools to generate information that can be used by the right geologists to find mines. The team is currently developing two such tools.
From the oil patch, 3-D seismics is being adapted to survey for sulphide deposits from 500- to >2,000-m depth, below the reach of conventional geophysics. At $50,000/km2, the technique is expensive, but it is the right tool for an area that already has mining infrastructure. Last year, this technology located a 15-million-tonne sub-economic massive sulphide deposit at a depth of 1,100 metres in New Brunswick.
The exciting Perseverance deposit near Matagami, Que., was recently found using leading-edge airborne electromagnetics technology.
With Falconbridge, Noranda is developing hyperspectral remote sensing. This aerial survey, flown at 6,000 m above the surface, uses reflected short wave infrared light to map the chemical alteration of rocks, seeing through lichen and even around trees. Scanners developed by Earth Search Sciences Inc. can map >3,500 km2 per day at a 10-m pixel resolution, greatly reducing unit costs and compressing the time line for gathering data. The technique has been used mostly in the arid regions of South America, but is also being used in boreal forest and the Arctic.