At the beginning of the present century the world's annual demand for copper was about half a million tons; the United States produced about half this total, whilst Britain's output had fallen to a mere token figure. Today the annual consumption is now more than nine times as large. This dramatic rise in the intervening sixty years can be attributed partly to population growth but mainly to the tremendous technological advances which have received impetus from two World Wars. In the Second World War the demand for copper most certainly could not have been satisfied, but for an invention in 1921, when Perkins patented his process of chemical flotation. This made it possible to mine ores which, up to that time, had been regarded almost everywhere as worthless. Some attempts at flotation of crushed ores had been made ever since 1860, but the process only became commercially important after the 1914-18 war. 29
The Raw Material
29 NEUBERGER, A. The Technical Arts and Sciences of the Ancients. (1930), p. 37.