Highland councillors yesterday opted not to object to the construction of the giant Coire Glas scheme planned for the hills to the north-west of Loch Lochy and the Great Glen.
The decision means Scottish ministers can decide whether to approve it without the need for a costly and time-consuming public inquiry, although councillors have attached a list of conditions.
They said one area of deep concern was the local impact of 12 HGVs full of rock leaving the site every hour for three years.
The same volume of traffic would arrive at the site for the collection of rock, and would mean a 73% rise in the numbers of HGVs on the A82 Fort William to Inverness road, which many councillors believe is not suited for such an increase in heavy traffic.
Members of the council's local planning committee said they wanted the developers to take away as much rock as possible by boat along the Caledonian Canal. Their biggest concern was the 400,000 cubic metres that will result from the tunnels being dug into the hillside, and what to do with it.
Local independent councillor Thomas MacLennan said: "Twelve HGV vehicles leaving the site very hour might not sound like much, but if you take a calculator to it, it will mean 90,000 vehicle movements, and 90,000 coming back to fill up. That's totally unacceptable."
He said Loch Lochy was part of the Caledonian Canal and should be used to take the rock out.
Lochaber councillor Allan Henderson said a lot of the rock could be used round Loch Lochy itself for reinforcing the A82 or building a picnic site out into the loch to encourage tourism.
The £800 million pumped storage scheme would be one of the largest construction projects in Scotland, creating around 150 jobs and taking a total of six years to build.
Councillors said that given the size of the project, it was inevit-able it would be approved by ministers, so the council's job was to make sure the local impact would be mitigated.
Meanwhile, across Loch Lochy at the Letterfinlay Lodge Hotel, owner Ian Cameron Smith said he had already been losing trade because of the proposed development.
He said: "As soon as we heard in February about the planning application, we had brides wanting to be married on our decking overlooking the loch wanting to cancel."
He said he was pleased the councillors had agreed to form a liaison committee on the planning conditions. "Hopefully that will allow us and other local businesses to get some kind of compensation."