The world’s biggest resort isn’t even open yet, and already MGM Grand executives are talking about expansion.MGM Grand president Bob Maxey has told Nevada gaming regulators that the hotel’s 33-acre amusement park may end up even grander after the $ 1 billion project opens Saturday. Maxey said that if demand is greater than anticipated, 10 acres currently planned for parking can be added to the amusement park at the 5,005-room hotel-casino. Maxey said the project, which includes a 171,500-square-foot casino, is the type of resort that will enable Nevada to compete with the expansion of gambling in other states. “This is what insulates us against being concerned about a riverboat casino or about an Indian casino,” he said. Maxey said Nevada’s long experience in gaming gives it a stability and predictability not found in other areas. “Gaming and tourism is the basic industry,” he said, and not a cure for poor planning or a method of creating jobs. MGM officials said the hotel has received nearly 100,000 applications for the 7,500 jobs inthe hotel, casino and theme park. Many of those jobs are at the center of a confrontation between the resort and Culinary Union Local 226, which wants the hotel to sign a union contract prior to opening. Hotel executives say they are willing to sign a union contract, but only if employees vote in a federally supervised election for union representation.