Mayor Melissa Blake told members of the Alberta Energy and Utilities Board that Fort McMurray is already financially unsustainable.

The population has more than doubled to nearly 75,000 in nine years, and the prospect of another C$100 billion (US$89 billion) in sands development over the next decade would mean the city could not keep up.

"They need to have a broader perspective when they're going into their deliberations in support or non-support of particular projects," she said.

She