Duluth, MN)  --  The northeastern Minnesota economy is shaking off its worst shipping season in decades.  Last year saw the sharpest decline in cargo volume since the Great Depression of the 1930s.  But regional economist from the College of St. Scholastica, Tony Barrett, says the twin ports of Duluth and Superior are on the way back.  He says it's not going to set any records, but grain and coal shipments look strong and the ports have become a major entry for wind turbines. Barrett says there is a cloud on the economic horizon because the region's taconite industry depends on national steel demand which has been lagging.