Geology Reference
In-Depth Information
12.6 The decrease of mineral endowment due to raw material
production
The method outlined previously could be used to assess both the mineral endow-
ment of the Earth's crust and its yearly depletion due to mining. However some
additional remarks need to be made. Recalling Fig. 4.2 one sees that the min-
ing process does not imply an immediate loss of the mineral exergy bonus of the
material itself. On the contrary, once extracted, it is elevated through further con-
centration and refining processes. The same happens when the material goes to
landfill. Indeed one only loses this bonus when materials cannot be recovered, i.e.
when a material arrives to Thanatia. This is the case of metallic pigments in paints,
zinc in tyres, phosphorous in car surface treatments, lead in petrol, phosphates in
agriculture, metals used as additives in steels, cadmium and other metal dispersion
in waste incineration, many electroplating materials, mine tailings and hundreds
more (see Angerer et al. (2009) for details). Also, all fossil fuels required to elevate
the exergy of materials, become degraded and slowly but irreversibly contribute to
Thanatia's form. Taking such considerations into account, one can now assess the
yearly depletion of the mineral capital endowment due to mineral production. For
this reason, world primary production figures such as those reported by the Mineral
Commodity Summaries (USGS, 2010) are required.
Table 12.3 shows the total exergy replacement costs of the studied production
chains. According to the authors' calculations, the exergy replacement costs (bonus)
associated with the 2008 production of the studied minerals is equal to 5.3 Gtoe.
It is worth noting that conventional economics only accounts for the energy
required in the extraction and refining processes. In the case of the materials stud-
ied, these account for around 10% of the globally produced fossil fuels 4 in 2008
(see Eq. (12.4)). The latter percentage lies within the range reported by the World
Watch Institute (up to 7% of the total world energy consumption) and by the IEA
(up to 10%).
In the authors opinion a fairer accountability of resources should also take into
consideration the use and the subsequent decrease of the non-fuel mineral capital
endowment. This means that the annual balance of minerals should account for at
least, the exergy of the world production of fossil fuels and the loss of the exergy
bonus of non-fuel minerals. As can be seen in Fig. 12.4, the latter represents 33% of
the entire energy and 40% should the mining, concentrating, smelting and refining
stages be included. Furthermore it is in the same order of magnitude as the yearly
loss of coal, oil or natural gas.
Fig. 12.5 also shows in a schematic way the gross mineral exergy bonus of the
extraction of the considered minerals for 2008. This bonus is not entirely lost.
4 In Eq. (12.4), the energy associated with the mining and concentration, smelting and refining
has been depicted as if it comes from coal. This is obviously a simplification, since energy can
originate from other fossil fuels or even from renewable resources.
 
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