A bill that changes the operating contracts for Iowa’s riverboat casinos has cleared the Iowa Senate, but it’s future is uncertain. Iowa regulators have been granting nine-year-long operating licenses to the casinos, even when the boats are sold. That means some of the boats have contracts which extend past the gambling timeframe voters approved in local, county referendums. Senator Sheldon Rittmer of De Witt says that’s a big loophole.The bill would tie the length of licenses to the timeframe established by gambling referendums, starting in 2010. The bill must clear a House Committee today, or it’s dead for the year.