Reporting from Denver - Interior Secretary Ken Salazar said Thursday that only 17 of 77 oil and gas leases on Utah public lands that the Bush administration auctioned off in December were valid and that his agency would prevent development on the remaining parcels, at least in the near future.Salazar spoke at a Washington news conference to announce the findings of a report he commissioned this year on the parcels, which became the subject of a fierce controversy during the waning days of George W. Bush's presidency.