ADM Penman, DSc, FICE. This paper was first published in GE’s March 1985 edition.
While travelling comfortably at 500mph, five miles above the earth’s surface sipping pre-dinner drinks, it is satisfying to contemplate the fact that all the materials to make the jet plane were won by man out of the earth’s crust. So also were the materials for motor cars, washing machines, refrigerators, freezers, central heating and air conditioning systems and all the other paraphernalia of civilised life that we all take for granted.
Man has been finding and digging up ores for copper and iron for a very long time. Many of the richest and shallowest sources have already been worked out and the mining industry today is having to handle ores that contain relatively little metal. In the copper industry alone, the quality of metal ore mined has been steadily lowering from 3 or 4% to 0.3-0.4% thereby considerably increasing the volume of rock that has to be processed to provide a given amount of metal.