Contaminated soil from Calgary arena site stored as far away as Brooks, Alta.

Every day, a parade of dump trucks arrives at the site of the future Scotia Place arena to pick up contaminated soil.

The four hectares (10 acres) of land used to be a parking lot for the Calgary Stampede. Before that, the site was covered with houses as part of the Victoria Park neighbourhood.

This fall, workers have been busy digging up two metres of top soil to be hauled away. More than 100,000 tonnes of material has been removed.

Bob Hunter, the city's spokesperson for the event centre project, said the soil must be sequestered because it's contaminated.

What's it contaminated with? Hunter said it relates to the previous land uses.

"The key ones there would be asbestos. And so we've taken great caution. We're testing constantly, almost daily," he said.

Besides asbestos, work has churned up foundations from former houses and old utility lines.

Some chemical substances have been found but not in any large quantities.

"They're manageable and they are removable, which is obviously a good thing. Hydrocarbons, that sort of thing. But generally they would have been associated with neighbourhood activities. So there was no heavy industrial contaminants found."

No archeological items have been churned up in the excavation.

As for what happens to the soil, Hunter said it's being hauled to two places.

One is a storage site on the outskirts of Calgary. But material is also being taken to a compound in Brooks, Alta., about 190 kilometres east of Calgary.

He said the Calgary site is taking only 10 deliveries of the contaminated soil per day, so the rest ends up going to Brooks.

Soil removal isn't the only work going on at the site of the $920-million arena.

Hunter said more than 475 piles have been driven into the ground. They'll provide structural support for the shoring that will be going in as work crews dig down into the site.

About 10 more metres of dirt will be removed so the foundation of the building can be developed.

He's calling it the big dig, and that work is expected to get underway in November and continue into the new year.

Plans call for the Scotia Place ice level to be more than 10 metres below street level.

The new home of the Calgary Flames will open in the summer of 2027.

The building will be owned by the City of Calgary. It will be operated by the Calgary Sports and Entertainment Corporation, which owns the NHL team and several other local sports franchises.