Geology Reference
In-Depth Information
It is worth reiterating that any exergy cost calculation for fuel minerals is non-
sensical as it is impossible to replace them with current technology. Furthermore,
the value of a given fossil fuel relies on its inherent chemical exergy, which once
burnt disappears along with its inherent usefulness. On the contrary, the chemical
exergy of metals and other non-fuel minerals does not generally disappear upon dis-
posal to landfill. Rather it is the concentrated state of minerals in deposits that is
eventually lost. Hence, whilst the natural bonus lost in fossil fuels is related to their
chemical exergy, that of non-fuel minerals is generally linked to the exergy costs
required to replace the minerals from the depleted state of the crepuscular crust
to the concentrated state once found in mines. Consequently, one can estimate
the exergy destruction of the global mineral resources by comparing the chemical
2,000
B*, ktoe
1,800
Zinc
Lead
1,600
Copper
1,400
1,200
1,000
800
Gold
600
400
200
Silver
0
Silver
Gold
Copper
Iron
Nickel
Lead
Zinc
Fig. 13.23 Natural exergy bonus exhaustion associated with the consumption of the main non-fuel
minerals in Australia from 1884 to 1906
6,000
B
*,
ktoe
5,000
Zinc
4,000
Lead
3,000
2,000
Iron
1,000
Gold
Copper
Silver
0
Silver
Gold
Copper
Iron
Nickel
Lead
Zinc
Fig. 13.24 Natural exergy bonus exhaustion associated with the consumption of the main non-fuel
minerals in Australia in the period from 1907 to 1964
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