Cliffs Natural (CLF), which produces iron ore and coal, is climbing in early trading after JPMorgan analyst Michael Gambardella upgraded the stock to Overweight from Neutral in a note to investors earlier today. The company's stock has dropped 37% since mid-September 2012, even though seaborne spot iron ore prices have surged 53% since that time, according to the analyst. The gap between iron ore prices and Cliffs' stock price is now at its widest point on record, Gambardella added. Cliffs has lagged due to the disappointing performance of its Bloom Lake iron ore mine, but the stock currently reflects the negative ramifications of the mine, he believes. Cliffs' shares should climb going forward as their leverage to iron ore prices should be strong over the medium term, contended the analyst, who raised his target on the stock to $40 from $35. In early trading, Cliffs rose 40c, or 1.5%, to $29.25.