Geology Reference
In-Depth Information
Strict environmental regulation in many countries has successfully led to more
e
cient technologies and new smelting plants operating with increasingly lower
emission levels. Electrostatic precipitators and desulphurisation plants have reduced
or even removed some environmental impacts especially those of heavy metals dust
and acid rain. They have also removed the issue of bioaccumulation associated
with particulate matter emitted from smelters, which became a very important
research matter in the 1980s and 1990s (Reichrtová et al., 1989; Leita et al., 1991).
Additionally, water treatment in a closed cycle is becoming a current technology.
Slag, should the metal concentrations contained within it be high enough, also
presents a future recycling opportunity using for example microbial processing
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.
In a foreseeable sustainable production of metals, green technologies and leg-
islation (which have already influenced the price of metals), will increase prices
further. Energy e
cient practices need to reduce energy costs and compensate for
additional energy and capital expenditures that serve to meet increasingly stringent
environmental regulations and international voluntary standards such as those of
the ISO series.
Investments in energy-e
cient and environmentally friendly technologies are
costly but necessary and could be compensated by an increase in metal prices on the
world market. However, modern smelting plants still do not consider CO
2
, capture
and storage as a feasible option, at least not in the short term.
7.7 Summary of the chapter
This chapter has provided an overview of the general techniques, impacts and costs
associated with the mining and metallurgical industry.
Exploration is the first and probably the most di
cult activity to be undertaken
before mining effectively starts. As the mines containing the best ore grades have
been already exploited, exploration needs to move to steadily more remote sites.
That said, there remain large areas still inadequately explored simply because it
is intrinsically very expensive to do so. There is also the problem of incertitude.
Indeed, exploration costs are also hard to evaluate whilst there is no standard
practice for the reporting of accounts. As such, generally speaking, accounting
topics cannot be reliably used for assessing the mineral capital on Earth.
After a commercially exploitable mineral deposit has been found, the next step is
the mining process, which can be either open-pit (surface mining) or underground.
The former requires less energy per tonne of material mined but its impact on land is
much higher than the latter. Mining operations are further classified as extraction
(which includes blasting, digging, drilling, dewatering and ventilation), materials
handling and beneficiation. The metallurgical processes then follow.
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Vitousek and Matson (1986) was among the first to suggest that microbial processing technolo-
gies offer opportunities to mine minerals that have remained uneconomical.
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