Smelting still dominates the copper industry is the title of an article by Virginia Heffernan in the September 2003 issue of Engineering & Mining Journal (pps. 22-24). North American output and capacity have, however, been declining recently at an alarming rate. In 1995 there were 11 primary and secondary smelters in the USA. Today there are only four.

The reasons for the decline are varied. In the 1970s-1980s, regulations under the Clean Air Act forced some US smelters to close and others to replace reverbatory smelting with newer, cleaner, flash smelting. Overall capacity, however, remained fairly steady, but recent changes are different. Reduced mine output has played a part, but so has the growth of an alternative, greener technology- solvent extraction-electrowinning (SX-EW). Other viable alternatives to traditional techniques, such as bioleaching and pressure leaching are also shown to have the potential to be much cheaper, cleaner alternatives to pyrometallurgical practices and, as a result, could soon steal significant market share from smelters.