The one-billion-dollar expansion of the Graton Resort and Casino is officially underway. A groundbreaking ceremony was held at the 254-acre property in Rohnert Park on Thursday. By the time construction is done, there will be a gaming floor nearly double the current size, two-thousand more slot machines, and 200-plus new hotel rooms. The casino, owned by the Federated Indians of Graton Rancheria, will become one of the three largest gaming facilities in California. This is expected to be Sonoma County’s largest commercial construction project in years.