When it opened in 1975 there were high hopes that Mirabel airport would become an international aviation hub, linked to the city of Montreal by a short train ride.

Those hopes were finally grounded this week as the board of directors of Montreal's airport authority approved a plan to demolish the terminal.

The city of Mirabel and other groups have long tried to find other uses for Mirabel airport since it was shuttered in November 2004, but James Cherry, the President and CEO of Aeroports de Montreal, said those plans were never financially feasible.

"Not only the cost of bringing it up to the norms of today, the cost of investing to put another use to it is too high, too expensive," said Cherry, pointing out that groups which examined the terminal building decided the conversion cost was too much.

"They would much rather have a purpose-built building that they can operate more efficiently, that they can operate more effectively from an energy point of view."

Maintaining the terminal costs millions of dollars per year, which is no longer feasible according to the airport authority.

Last May, Aeroports de Montreal called for tenders to demolish the terminal, upsetting many including Mirabel Mayor Jean Bouchard,who said the building could have been converted into many things, including a trade centre.

"Everyone was in favour of the plan," sad Bouchard. "We're asking ADM to give us a reprieve."

Cherry said those plans never materialized nor were guaranteed financing and the deal would have been hampered with conditions, which ultimately affected their decision to move ahead with the demolition.

The first phase will be to decontaminate the structure; the second to demolish.

ADM estimates the total cost will be less than $15 million, far less than the $25-35 million it would cost to upgrade the building.

The airport authority stresses the property will still be used.

“We're not affecting the airport. The airport's vocation is continual. There are still two runways there. They're still cargo taking off every day there. There are airplanes being built there, engines being tested. We're talking one building on the site that used to house passenger activities that we haven't used - that's been empty for ten years,” said Cherry.

Cherry believes the start of the decontamination process could begin as soon as December.