June 30 (UPI) -- Colorado voters must turn in their ballots by 7 p.m. MDT Tuesday in the state's primary elections to have their vote count in several hotly contested races. Up for grabs are the governor , secretary of state, U.S. Senate and eight House of Representatives seats, plus state offices. The deadline to mail ballots has already passed, so voters must hand-deliver their votes to one of the state's 137 voting centers or 437 drop boxes. More than 783,000 ballots were returned by Tuesday