Geology Reference
In-Depth Information
Chapter7
An Introduction to Mining and Metallurgy
7.1 Introduction
In the previous two chapters, a review of the geological and geochemical characte-
ristics of the Earth was undertaken, emphasising the quality and quantity of the
resources useful to Man. Now the aim is to analyse how society extracts and re-
fines the raw-materials provided by Nature. Given the wide variety of minerals and
conditioning facts, it is di
cult to generalise these activities as well as their environ-
mental impacts. This is why in this chapter an introduction to the main physical
processes, costs and impacts appearing in the mining and metallurgical industry
(exploration, mining, smelting and refining) as well as the reclamation of land once
the mine is closed are offered, serving as an introduction to the more specific and
detailed analysis of the metallurgy of key minerals explained later in Chap. 8.
7.2 Exploration
The mineral wealth of a region, country or even of the planet as a whole can only be
known after its exploration. As the planet has been fairly explored, serendipity only
exists for qualified professionals. Modern exploration is a dynamic and expensive
process that is done in stages and only very few exploration projects ultimately
become mining properties, typically in the order of 1%. Mineral exploration is the
process of systematically analysing the presence or absence of mineral deposits in
large enough concentrations for commercial extraction (Bateman and Jensen, 1981;
Revuelta and Jimeno, 1996). Geochemical sampling, ground geophysical surveys
and even preliminary drilling is undertaken. This then enables an estimation of
potential ore grade, quality and tonnage of the new found deposit.
With declining ore grades, exploration is increasingly focused on finding hid-
den deposits below the surface. Hence, exploration demands substantial financial
resources with strong degrees of incertitude. In fact, few countries have comprehen-
sively evaluated their deep geological structures and large remote areas still remain
inadequately explored. This phenomenon results from a lack of information which
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