The Exergy Evolution of Mineral Wealth - Thanatia: The Destiny of the Earth's Mineral Resources - page 409

Table 13.4: The peak in production of some of the world's important mineral
commodities. - continued from previous page.

Theoretical Data Empirical Data

R 2 W.R. Peak R 2 Observed Peak

Reserves Peak

Chromium 2015 0.96 2149 0.97 -

Cobalt 2042 0.87 2073 0.88 -

Copper 2012 0.95 2068 0.98 -

Gold 1994 0.65 2001 (R.B.) 0.74 2001

Iron 2040 0.91 2115 0.92 -

Lead 1989 0.82 2110 0.82 -

Lithium 2015 0.86 2033 0.89 -

Manganese 2007 0.87 2119 0.81 -

Mercury 1960 0.56 1965 0.18 1971

Molybdenum 2018 0.95 2040 0.95 -

Nickel laterites 2017 0.98 2033 0.98 -

Nickel sulphides 2017 0.98 2033 0.98 -

Phosphate rock 2031 0.92 2080 0.89 -

Potash 2072 0.91 2272 0.88 -

REE 2092 0.98 2104 (R.B.) 0.98 -

Rhenium 2022 0.95 2054 0.94 -

Silver 1995 0.44 1999(R.B.) 0.52 -

Tantalum 2034 0.85 2046 (R.B.) 0.85 -

Ti-ilmenite 2040 0.96 2082 0.96 -

Ti-rutile 2028 0.89 2069 0.86 -

Tin 1979 0.53 1986 (R.B.) 0.63 -

Uranium 2033 0.72 2061 0.70 -

Vanadium 2067 0.83 2129 0.83 -

Wolfram 2007 0.89 2036 0.87 2004

Zinc 1999 0.92 2062 0.98 -

Zirconium 2003 0.89 2006 0.89 -

As explained in Sec. 13.2, the Hubbert Peak is a theoretical model that can be
used to predict future supply/demand dynamics, subject to certain limitations. In
Table 13.4, it is clear that for certain minerals, the bell-shaped curves do not fit the
empirical data well. Mercury, arsenic, beryllium, silver, tin, antimony uranium and
gold all show regression values below 0.80. The Hubbert Peak Model as applied in
this topic (with the constraint that the integral of the curve is equal to resources)
applies well when the main criterion of future supply/demand dynamics is geological
availability. In general, regression factors increase with the peaking year, as empir-
ical points fall to the foot of the curves. Equally, and as observed in the Australian
case study, the empirical peak associated with reserves regularly appears after the
theoretical one. This might relate to the over-exploitation of minerals for a short
period, followed by its sharper decrease in those years following the peak. It may
also be due to the perceived certainty of mining companies that their reserves could
easily increase despite having reached what the authors would term the “theoretical
peak”.
Yet even with the aforementioned limitations, the Hubbert Peak Model does
however identify that the theoretical peak could have been reached, in terms of