Groundbreaking work was to start Monday at the site of the planned casino just outside Rohnert Park, said the Sonoma County tribe behind the project.

The grading "signals the start of the nearly 900 construction jobs that will be created by the tribe's project," said a statement by Federated Indians of Graton Rancheria.

Unanswered questions remained Monday morning about whether the work was starting ahead of required approvals.

The tribe's 254-acre Wilfred Avenue property is exempt from virtually all local and state regulations, but official statements and documents have indicated there are steps that the tribe agreed to that must be completed before groundbreaking.

Neither tribal nor county officials immediately returned calls seeking comment Monday. Station Casinos, the Las Vegas-based corporation bankrolling the project, declined comment.

Monday morning, a large tiller sat at the site, located south of Home Depot along Wilfred Avenue.

The heavy equipment is to be used to break up earth in advance of the grading, said David Sawyer of the tribe's environmental consultant, Sacramento-based Analytical Environmental Services. Sawyer and a biologist were at the site to monitor the work.

The agreement, or compact, between the state and the Federated Indians of Graton Rancheria allowing the tribe to start work is awaiting final approval by the federal Department of the Interior, which has not announced a decision.

The compact requires the county and tribe to reach agreement on how the tribe will financially address the the impacts of the planned 3,000-slot machine casino.

And at hearings in May in Sacramento, a senior advisor to Gov. Jerry Brown said work on the project could not start until that county-tribe agreement is in place. County officials have said that negotiations are to begin once the federal government makes its decision.

But the tribe's statement said that Sonoma County Counsel Bruce Goldstein had confirmed at a public meeting at the county Board of Supervisors last week that "the tribe has the right to start construction of the project prior to that agreement being concluded."

What Goldstein said at that meeting was that he could not find in the compact any language preventing the tribe from starting work before the agreement was reached. He said, however, that he didn't know whether the state had a separate requirement he wasn't aware of.

Casino foes said the development showed the tribe had broken its word and was ignoring the deals it had agreed to.

"Obviously the compact doesn't mean anything because they weren't supposed to break ground until they were done negotiating with the county," said Chip Worthington, a Rohnert Park pastor who has led the opposition for nearly a decade.

"So much for the governor's authority," he said.

You can reach Staff Writer Jeremy Hay at 521-5212 or jeremy.hay@pressdemocrat.com.