TOWER, Minn. (AP) — Electricians have restored power to the lowest level of a deep underground iron mine in northern Minnesota after a fire broke out last week.

The Minnesota Department of Natural Resources says power was restored to the 27th level of the mine at Soudan Underground Mine State Park about 5:45 p.m. Tuesday.

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The DNR calls that an important milestone, but says the park remains closed until a safety inspection can be completed.

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Tours of the mine and the University of Minnesota particle physics lab have been suspended indefinitely.

Up to 35,000 people a year take guided tours of the historic mine and the underground physics lab.

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