In 1800, global production of copper was 14,000 tonnes. By 1900, it reached 495,000 tonnes, a 35-fold increase. But by 2000, production hit 13,212,000 tonnes, nearly 1,000 times what it was two centuries ago [right, credit Mining Magazine].
The United Kingdom was the world leader in copper until about 1850. However, in 1900, the US produced over 55% of the world's copper. By 2000, the US was the second largest producer at 11%, far behind Chile at nearly 35%.
These figures come from a richly detailed article in the November 2011 issue of Mining Magazine, entitled "The Copper Conundrum." Author Phillip Crowson looks at world copper production from 1770 and found that "the average percentage yield of copper from mining has tended to decline over the long term, but by no means evenly." Cornish mines in the 1770s mined copper with an average grade of 12.17%. This dropped to 9.27% in 1800; 2.61% in Michigan by 1900; 0.85% worldwide by 2000; and to 0.77% worldwide in 2008.
Crowson warns there are lots of gaps in the data as many companies kept numbers proprietary. There are also widely divergent strategies, company by company, and country by country, in how to produce ore grades under different economic situations.
Still, there is no question that the big, rich, surface deposits of copper have been tapped out. Companies are pursuing deeper or lower grade deposits to meet the phenomenal global demand for this industrial mainstay. For example, the proposed Resolution Copper mine near Superior, Arizona, is going down to 7,000 feet after copper ore with a grade of 1.5%, about twice the current global average.