The arena, seating 11, 000 people, could also be used for concerts, sport and conferences.

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But he now believes reducing capacity and reconfiguring seating at the 2012 arena would make it viable for both athletics and football to exist together.

BBC: UK Athletics boss Ed Warner boosts West Ham's 2012 plan

Temporary seating and venues, like the 12, 000-seat Basketball Arena, will accommodate nearly 300, 000 spectators during the games -- a figure without precedent at any previous Olympics, according to organizers.

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Sheffield Arena is to have its first major upgrade since it opened in 1991, with a new roof and seating planned.

BBC: View of the arena seating

But the new arena, which will be run by Ballmer and Hansen, will add tens of millions of dollars a year from premium seating, sponsorship and non-NBA events that the Kings currently do not get at Sleep Train Arena.

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