The once-bustling construction site next to Thunder Valley casino looks like a high-rise ghost town, with pillars and rebar and empty cranes that disappeared into the fog Wednesday. And no workers.

It feels like Placer County's version of the half-built Elk Grove Promenade mall – only taller. Both projects were halted midstream by the lagging economy.

Work on the casino expansion stopped last month, idling 350 people employed by Thunder Valley contractors and subcontractors.

But construction is expected to begin again by late spring or early summer, said Doug Elmets, spokesman for the United Auburn Indian Community, which owns and operates the casino.

The goal is to complete construction by 2010 as scheduled when ground was broken for the project in July, Elmets said.

The question that remains is how big the expansion will ultimately be.

The original plan, estimated to cost $1 billion, called for a 23-story hotel with 624 rooms, a nine-story parking garage with 5,000 spaces, performing arts center and more.

"Like most businesses, we are trying to gauge future market demand," Elmets said. "There is no question that Placer County and the region need a large hotel and the casino needs more parking. But will we need nine stories of parking or as many suites as we planned?

"The tribe … decided to step back and reassess and at this stage of the development of the project, they were able to do just that."

Elmets said last month's opening of the $530 million Red Hawk Casino, on Highway 50 in Shingle Springs, had no bearing on the Thunder Valley decision to proceed with the expansion.

"The reality is there are 5 million people within a 100-mile radius of both Thunder Valley and Red Hawk," he said. "The number of people visiting Thunder Valley continues to grow, especially during the holiday season, but in this economy, people are just not spending as much."

Elmets would not discuss the casino's revenue, but gaming analysts have estimated Thunder Valley's annual profits to be between $400 million and $500 million. Some analysts says Thunder Valley is among a handful of the most profitable casinos, Indian or otherwise, in the country.

Representatives of Red Hawk, owned by the Shingle Springs Band of Miwok Indians, would not discuss the new casino's revenue projections.

But Bill Eadington, of the Institute for the Study of Gambling & Commercial Gaming at the University of Nevada, said in November that Red Hawk could generate $250 million a year, "even in a recession."