A stunning rebound in the international price for tungsten after a multi-year slump is good news for a proposed mine in central New Brunswick, even though its future is still uncertain.

The Sisson Brook project, a proposed open-pit tungsten and molybdenum mine that has been studied on and off since 1979 and finally has all of the permits it needs to proceed, still seemed a long shot to happen in recent months because of depressed prices for both the metals it contains.

But over the summer, international tungsten prices surged dramatically, climbing 50 per cent since mid-June. That put the value of tungsten back in the territory contemplated in Sisson's original economic feasibility study and gives renewed hope to its supporters.

"It would be good news to hear things are where the mining company can start and get things moving," said Juniper, N.B., resident Raymond Rousselle, a longtime backer of the mine who helped form a community group to support it called the Juniper Co-Operative.

"It would be a big boost. I'm not just talking about Juniper but the entire surrounding area — Stanley, Florenceville, Bristol. All those areas would really benefit."

Northcliff Resources Ltd. is the company behind the mine and did not immediately respond to a request for comment Wednesday, but the company did make note of the recovery in tungsten prices in its latest regulatory filing.

"Prices have been trending upward," it said.

Low prices comforted opponents

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Moncton Northwest MLA Ernie Steeves has previously suggested the Sisson mine near Fredericton is not financially viable. (CBC)

Opponents of the mine have long taken comfort in the belief that low metal prices would render the mine a non-starter.

Moncton Northwest Progressive Conservative MLA Ernie Steeves, who worries about the mine's proximity to the Nashwaak River watershed, told the legislature seven months ago he saw no chance the mine would be developed.

"It's not financially viable," he said in February. "In 2014 the price of tungsten was right up there. It's not now."

The Sisson project underwent a feasibility study in early 2013 after tungsten prices peaked at $460 US/mtu in 2011. (An mtu represents 10 kilograms of tungsten.)

The project was evaluated to be profitable over a 27-year period at an average long-term tungsten price of $350 US/mtu, but by last year international prices had collapsed to nowhere near that level, hovering at $195 US/mtu.

Those low prices persisted right into the early part of this year until a furious rally that began late in June sent tungsten soaring.

Curtailed production in China behind price jump

By last week it was trading at $320 US/mtu, an amount that is actually higher than that relied on by the Sisson feasibility study after factoring in the low Canadian dollar.

The rally was caused largely by a curtailment of production in China, the world's dominant tungsten producer.

Northcliff received final environmental approval for the Sisson mine from the federal government in June, just before the rebound in tungsten prices, but has given no indication when it might make a final investment decision on whether to proceed.

There are still significant risks facing the development.

There is no guarantee the rising price of tungsten will hold.  Also, molybdenum is meant to make up about one quarter of the income from the project but its price also collapsed years ago and has not recovered.

So far investors have not seen the tungsten price rally as a reason to embrace Sisson.

Northcliff's stock price actually fell 20 per cent during the tungsten resurgence, sinking from 19.5 cents per share on June 29 to 15.5 cents at close of trading Wednesday.