Magnitude of Pebble prospect unearthed

VALUE DECLINES: Despite massive mineral potential, metal prices falling rapidly.

December 5, 2008 

Four hundred and seventy six drill holes later, we now know the rough size of the giant, controversial Pebble deposit.

The copper and gold prospect in salmon-rich Southwest Alaska holds about 72 billion pounds of copper and 94 million ounces of gold, according to the estimate published Thursday by one of the companies advancing Pebble.

What's the value of all that metal?

At today's swooning metal prices, Pebble's mineral resource is still worth about $236 billion. But six months ago, when metal prices were soaring, the same amount of copper, gold and molybdenum was worth $500 billion.

Those numbers don't include the cost of prying the metal from the rock or harnessing the electricity needed to power a massive, remote mine. The project -- deeply controversial for some Alaskans because of its location near the headwaters of two rivers that feed the world-class Bristol Bay salmon fisheries -- could turn out to be uneconomical to build despite the huge value of the minerals there. The mining companies with rights to Pebble are a couple of years away from deciding whether to build a mine.

Pebble critics include commercial and sport fishermen, villages located downstream of the mine, environmentalists and hunters. Many of them hope to prevent any future mining in the drainages where Pebble is located because they are worried about a mine polluting salmon streams.


Thursday's estimate doesn't tell regulators or the public the amount of ore that would be mined at Pebble, though the estimated footprint of the mine is 15 square miles. Its developers, London mining giant Anglo American and the Canadian junior Northern Dynasty Mines Ltd., are evaluating building an open pit as well as an underground mine. They would have to build massive dams behind which they would store billions of tons of rock waste. And they have to find a source for electrical power.

So what's the point of these interim numbers?

"It's giving you an idea of the maximum potential size" of Pebble, said Tom Crafford, a large-mine coordinator for the Alaska Department of Natural Resources.

Before a mine could be built, the companies advancing Pebble would need to convert this estimate into something called a "reserves" calculation. That's how much metal could actually be mined profitably, Crafford said.

Pebble officials claim the recent drop in metal prices will not have a significant impact on deciding whether to build the mine.

The mine, as envisioned, would operate for roughly 50 years, and it's the prices during that span that matter.

The companies involved will use long-term metals price projections -- not current prices -- to determine whether Pebble is feasible, said Pebble spokesman Mike Heatwole. At the earliest, the companies plan to begin applying for permission to build the mine in 2010. If approved, construction at Pebble wouldn't start until 2012 or later.

On the other hand, current metals prices could have an impact on Pebble's budget -- the money used to develop the project, Heatwole said.

"Everyone definitely pays attention" to metal prices, he said.

Find Elizabeth Bluemink online at or call 257-4317.

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