From an interesting article:

http://www.stockhouse.com/Columnists...

"Possibly the most significant action in commodity markets today may be the significant rally in the price of copper. Copper tends to respond more to traditional supply and demand factors and less to political, financial, and weather concerns than other commodities. As such, copper tends to be viewed as an indicator of sentiment toward global economic growth prospects. In recent weeks, copper had been trending lower, but after successfully testing $3.00/lb earlier this month, it started to recover. Today, copper broke through resistance at $3.20/lb, suggesting that investor sentiment may be changing in response to the economic news and that an advance to test resistance near $3.35/lb may be underway."