02/21/2014 09:57 EST | Updated 04/23/2014 05:59 EDT

Large sinkhole on Ottawa light rail tunnel site, cause unknown

The cause of a large sinkhole at a downtown Ottawa intersection is not yet known, but it happened at the construction site for the eastern entrance to the light rail tunnel.

Ottawa police reported a sinkhole on Waller Street, just south of Laurier Avenue, at about 1 a.m. Police said the road collapsed leaving a hole that was about eight metres wide and 12 metres deep on the Transitway near the University of Ottawa.

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A news release from the City of Ottawa confirmed the sinkhole formed where workers had been tunnelling for the eastern portal of the Confederation Line LRT project.

It said work crews from the Rideau Transit Group had begun 24-hour tunnelling operations on Wednesday, and that they were working at the site when the sinkhole formed.

No one was injured.

Tunnel work suspended

The city also said tunnelling operations have been suspended while officials investigate.

Rideau Transit Group officials have also started to fill the hole with concrete to stabilize it, the release added.

Water, sanitary and storm services to 50 Laurier Ave. are affected because the city had to cut them off for the work.

Traffic and buses are being detoured and Laurier Avenue is closed eastbound between Queen Elizabeth Drive and Waller.

There's a briefing scheduled for 1 p.m. to update the public on the sinkhole and LRT construction. The city cancelled a 1:15 p.m. news conference for the one-year anniversary of the light rail contract.