Unions have organized a big slice of Thunder Valley Casino's work force at a time when the gaming industry is struggling under a weak economy.

About 810 drivers, food-service workers and others are joining either Unite Here or the Teamsters, depending on the job category, according to a Teamsters announcement.

The unions will represent about 40 percent of the Lincoln casino's work force. Excluded are about 1,100 dealers, cashiers and others typically not unionized at casinos, said Howard Dickstein, a lawyer for Thunder Valley's owner, the United Auburn Indian Community.

Thunder Valley becomes the second major Sacramento-area casino to be unionized, following Cache Creek Casino Resort in Yolo County, Dickstein said.

Dickstein said Thunder Valley officials anticipate a "productive relationship" with the unions.

"Ultimately, it was the employees' decision, not a decision of the casino management or the tribe," said casino spokesman Doug Elmets. "We will honor their decision."

Led by Unite Here, labor organizers persuaded more than half of the affected workers to sign union cards, a process known as "card check," Dickstein said.

Under federal law, the tribe could have challenged the card check and forced a formal vote. But the tribe chose not to. Under a "carefully crafted" agreement it made with labor in 2005, the tribe had pledged not to challenge any organizing efforts, Dickstein said.

In return, labor surrendered the right to strike, among other things, he said. Labor also agreed to support the tribe's new state gaming compact when it came before the Legislature for approval, he said.

"Each party got certain benefits," he said.

Besides the 810 workers covered, another 200 workers to be hired at Thunder Valley's new hotel also will be unionized, according to the Teamsters announcement. The 400-room hotel is scheduled to open next summer.

The labor effort comes about seven months after Thunder Valley laid off nearly 100 workers to cope with a downturn in business. Many casinos around the country have downsized during the recession.

The layoffs might have helped the unions' cause. Fearing for their jobs, workers might be more likely to put their faith in a union, said Nelson Rose, an expert on Indian gaming law at Whittier Law School.

Officials with Unite Here also have said they plan to try to organize the region's newest gambling venue, the year-old Red Hawk Casino in Shingle Springs. A spokesman for Red Hawk declined comment, but experts said the breakthrough at Thunder Valley could influence organizing efforts in Shingle Springs.

"The workers there are going to want to see what happens" at Thunder Valley, Rose said.

In a news release, Teamsters officials said they will try to organize another casino early next year without identifying the target. Jim Tobin, secretary-treasurer of Teamsters Local 150 in Sacramento, declined to comment. Efforts to reach Unite Here officials were unsuccessful.

Rose said unions generally have struggled to organize Indian casinos. But he said labor's hand was strengthened when a federal appeals court, ruling in a San Bernardino County case, declared in 2007 that tribal casinos are subject to federal labor laws.