Introduction - Metals and Society: An Introduction to Economic Geology - page 8

Table 1.1 Time before exhaustion of a selection of metals, as estimated in 1972 and 2009
Meadows et al. (1972) Mining Environmental

Management

Number of
years
(1972 - S)

Year when
metal is
exhausted (S)

Number of
years
(1972 - L)

Year when
metal is
exhausted (L)

Number
of years
(2009)

Year when
metal is
exhausted

2003 + Aluminium 31* 55 2027 131 2140

Copper 21 1993 48 2020 32 2041

Gold 9 1981 29 2001 16 2025

Iron 93 2065 173 2145 178 2187

Nickel 53 2025 96 2068 41 2050

Silver 13 1985 42 2014 13 2022

Zinc 18 1990 50 2022 17 2026

*Number of years before the metal becomes expensive and its supply limited
1972 (S) - exponential index of Meadows et al. ( 1972 )
+Year (S) - year during which metal is exhausted
1972 (L) - exponential index of Meadows et al ( 1972 ) using an estimate of resources five times
greater than those known in 1972
2009 - estimate of Mining Environment Management

copper and other metals that is recycled and reused by industry will continue to
mount in future decades.
Many authorities now predict that supplies of metals and other mineral products
are sufficient to meet societal needs for the foreseeable future. Other negative
consequences of population increase, correctly identified by Meadows et al.
( 1972 ), will be far more drastic. Even though the rate of population increase will
diminish with improvement in the standard of living and level of education in
developing countries, the addition of one to three billion people will put a severe
strain on all the earth's resources. Increasing competition for water and food, the
increasing effects of pollution, climate change, the increased energy requirements
for processing low-grade ores, and to a far lesser extent an increasing scarcity of
petroleum, will severely test humanity's capacity to adapt. Nonetheless, although
the long-term outlook is difficult to predict, we argue that the supplies of copper and
most other mineral products will NEVER be totally exhausted. To understand this
argument we must now consider in more detail the nature of an ore deposit.

1.3 What Is an Ore?

According to one commonly accepted definition, an ore is a naturally occurring
solid material containing a useful commodity that can be extracted at a profit .
There are several key phrases in this definition. By “useful commodity” we mean
any substance that is useful or essential to society, such as metals, or energy
sources, or minerals with distinctive properties.