The Exergy Evolution of Mineral Wealth - Thanatia: The Destiny of the Earth's Mineral Resources - page 391

tor RF is 0.98. Of course these numbers are only hypothetical and will presumably
increase, as new deposits are found.
Fig. 13.22 The Hubbert Peak applied to Australian natural gas reserves
13.3.10 Summary and discussion of the results
Table 13.1 summarises the results obtained, including the anticipated year of max-
imum production (as indicated by the peak), the static R/P ratio of the latest
recorded year, the depletion degree of the commodities (% R. loss), the quantity
of metal extracted (MtMe) in Mtonnes, the exergy replacement costs (natural
bonus, B ) and degradation velocities ( B ) of Australian fuel and non-fuel mine-
ral reserves throughout the given period (t). Since exergy is an additive property,
the total exergy replacement costs of the mines considered can be also calculated.
The Hubbert Peak Model corresponding to the exergy reserves of the Australian
minerals considered satisfactorily applies to gold, copper, nickel, iron, coal, oil 9 and
natural gas. This was not the case for silver, lead or zinc, where the regression
factors of the curves were low and the latest production points did not fall under
the bell-shaped curve. As the production of all three metals are closely related, it is
perhaps not unreasonable that the general behavioural pattern is not followed. With
the aforementioned limitations, according to the economic demonstrated reserves
of the listed minerals, the Hubbert Peak Model applied in this topic predicts that
the maximum production has been already reached for zinc (2012), silver (2009),
gold (2007), oil (1996) and lead (1994). The theoretical peak for copper is 2026, for
natural gas, 2029, iron should be in 2030, nickel in 2039 and finally coal in 2047.
9 Despite irregularities in oil production, the model successfully predicted peak production, within
a discrepancy of four years.