Some of the bids submitted for work on the $975 million Minnesota Vikings stadium are higher than what the Minnesota Sports Facilities Authority expected. Although not all portions of the project have gone to bid, costs are running up to $30 million higher than what was budgeted. The Vikings said they would put up an additional $13.1 million, but it will take value engineering to keep costs contained. The lack of skilled construction workers appears to be one of the factors for the higher costs. "As the work begins to increase, firms are having to pay a lot of overtime to people they still have," said Ken Simonson, chief economist for AGC. "And soon, if it's not happening already, we are going to start hearing about wage increases for starting workers."