Mining Methods Vary Widely - Mining and the Environment: From Ore to Metal - page 218

5

Mining Methods
Vary Widely

From Excavation to In situ Leaching

This chapter has several purposes. First, it illustrates that mining is not restricted to
extracting metals, coal, or diamonds; mining also includes the wide range of operations
to extract dimension stone; sand and gravel; clay, ceramic, and refractory minerals;
chemical deposits and fertilizer minerals; and other non-fuel, non-metallic minerals.
The mining method will depend on the type of material and its mode of occurrence.

Second, it outlines common mining methods. Surface and underground mining as dis-
cussed in Chapter Four are revisited, before the concepts of solution mining and heap
leaching are introduced. Heap leaching is a relatively common process used for the recov-
ery of base metals and precious metals (gold and silver) from amenable low grade ores or,
occasionally, from previously processed tailings or from past waste rock dumps.
Third, the chapter discusses artisanal mining which, while it represents a traditional way
for many people, also has the potential to cause severe environmental damage. Artisanal
mining is dei ned as small-scale mineral extraction, using mainly manual methods, carried
out by individuals or small family groups. Other terms in common use are 'small-scale min-
ing' and 'illegal mining', the latter when artisanal mining is carried out on a tenement grant-
ing exclusive mining rights to others. Occasionally, artisanal mining can be at the scale of
commercial mining when backed by wealthy businessmen and supported by government.
Finally, this chapter is intended to reinforce the fact that mining ultimately contributes
to a better life for the 6 billion people who depend on the raw materials it produces.

Mining ultimately contributes
to a better life for the 6 billion
people who depend on the raw
materials it produces.

5.1 THE THREE MAIN CATEGORIES OF COMMERCIAL
MINERALS

A common classii cation of commercial minerals into three main categories is based on the
primary elements in the ore ( Table 5.1 ) : metallic ores, non-metallic ores including gem-
stones, and mineral (fossil) fuels.