What was once the largest stadium in the National Football League was scheduled to fall Sunday, but the first detonation failed to bring down the upper section of the structure.

The blast did weaken the Pontiac Silverdome, opened in 1975 and able to seat 82,000 fans. It could still fall, but the timetable is uncertain, said officials with Detroit-based Adamo Group, the demolition company.

Ten percent of the explosive charges failed to go off because of a wiring problem, said Rick Cuppetilli, executive vice president with Adamo. These were in eight key locations.

"Unless we find something in the next few hours researching the wiring, we will take it down mechanically," Cuppetilli said. "We haven't found the wire yet. It's going to take us a while to research it all."

Excavators will be used this week to take out the structure unless gravity causes it to fall on its own before then, Cuppetilli said.

So far the company has no plans for a second explosion attempt.

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