I have read a number of articles over the past few years about Dr Copper - how the price of copper is an indication of the health of the economy. I actually think that still it is BUT I think people should be looking at Copper consumption not copper price. Iin the following article, I found this comment insighful about copper prices:

"The financialization of commodities has meant that their prices are increasingly driven by the ebb and flow of investor sentiment and positioning, rather than solely by ‘real’ demand,”

http://www.kitco.com/news/2015-08-20/Commodity-Slump-Not-Necessarily-Signaling-Recession-Capital-Economics.html