Physical Geonomics: A Cradle-Grave-Cradle Approach for Mineral Depletion Assessment - Thanatia: The Destiny of the Earth's Mineral Resources - page 87

Chapter4
Physical Geonomics: A
Cradle-Grave-Cradle Approach for Mineral
Depletion Assessment
4.1 Introduction
Physical Geonomics, as proposed in this topic, is interpreded as a branch of Exer-
goecology which is used to account, through the exergy replacement costs, the effort
required to restore a given mineral from a dispersed state to its original concentra-
tion when found in a mine. It thus addresses the problem of resource depletion and
is the theoretical framework for the numerical assessments carried out in Part 3 of
this topic. The Physical Geonomics approach allows for the determination of the
missing semicircle of a complete cradle-grave-cradle analysis of the mineral wealth
on Earth. This chapter explains in detail the methodology behind the approach
together with the concept of thermodynamic rarity.
4.2 Material cycles and the dispersion problem
The planet works in cycles driven by solar energy. Such cycles include that of car-
bon, oxygen, nitrogen, phosphorus, sulphur or water. As of yet however, there are
no postulated cycles for metals and chemical elements generally. Of the latter, those
associated with biota have short closing cycle times, even if measured on a geolo-
gical scale and can be replenished quickly (provided that any anthropogenic waste
production should not exceed the assimilative capacity of the biosphere). As for
those not involved in biological life they are far from readily or easily restocked in a
human based timeframe. They are constituents of mankind's “exosomatic” organs
and include buildings, infrastructures and machinery whose deterioration and obso-
lescence causes metal dispersion. Indeed exosomatic materials need geological eons
to naturally close each particular element cycle. Restoring mineral deposits, thus,
to the way they were before civilisation, would only be possible using together the
internal heat of the Earth through volcanism and the weathering processes driven
by the sun. If Man was to effectively set about turning back time, the “easiest”
mineral resources to restore would be the fossil fuels. And this is despite the fact
that fossil fuels have a formation time in the order of millions of years 1 .
1 Giampietro and Pimentel (1991) gave a value for fossil energy productivity of the Earth as low
as 0.016 MJ=m 2 =day or 1000 kcal=0:7m 2 =year.
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