Introduction - Metals and Society: An Introduction to Economic Geology - page 7

Fig. 1.3 (a) The predictions
of Meadows et al. ( 1972 )of
the evolution of global
population and of the supplies
of raw materials. (b)
Predictions based on the idea
that supplies of natural
resources will be rapidly
exhausted, leading to a
catastrophic decline in
population
sufficient copper for the next two to three decades in deposits that can be exploited
using current technology, there is no point in finding more.
The second influence that was not sufficiently well taken into account by
Meadows and co-authors is the impact of improvements in technology, which has
allowed even low-grade deposits to be mined efficiently, and the metals and other
mineral products to be extracted economically. Later chapters provide striking
examples of the evolution of mining and extraction technologies.
A fundamental difference between the long-term production of metals and
energy sources such as petroleum, coal or uranium, is that once an energy source
has been used by industry or society, it is gone for good. The fossil fuels disappear
up smokestacks as they produce heat; the radioactive elements decay definitively to
their daughter products. Metals, on the other hand, persist. Copper remains copper
when it is used in telephone wires, in iPhones or on cathedral roofs, and in most
cases it can be recovered at the end of the product's lifetime. The proportion of