Prices for U.S. Treasuries jumped on Thursday after a strong sale of 30-year debt underscored demand spurred by the looming "fiscal cliff" and fears about the eurozone debt crisis. In its final refunding auction of the week, the U.S. Treasury sold $16 billion of 30-year bonds at a high yield of 2.82%. "The bond auction came strongly through, with impressive stats across the board," Nomura analysts wrote in a note to clients. At 2.77, the