Environmental Engineering Reference
In-Depth Information
Table 3.3 Mining and separation technologies employed at present [ 23 ]
Resource
Mining techniques
Extraction techniques
Iron
Surface mining (open pit mining)
Smelting and chemical reduction
Gold
Underground mining (shaft mining)
and surface mining
Gold cyanidation is used. The ore is
chemically treated to extract the gold
Copper
Surface mining (open pit mining)
Leaching is used to extract the copper
using an acid
Platinum
Underground mining (shaft mining)
Chemical methods and as a byproduct
of copper mining
Zinc
Underground mining (shaft mining)
Smelting and leaching
Chromium
(Chrome)
Surface mining (open pit mining) and
underground mining (shaft mining)
Smelting, redox reactions
Manganese
Surface mining (open pit mining) and
underground mining (shaft mining)
Smelting and chemical processes
Diamonds
Surface mining (alluvial deposits) and
underground mining (pipe mining)
Diamonds are extracted from rocks and
in almost pure form
Phosphate
Surface mining (open pit mining)
Treatment with acid
Asbestos
Surface mining (open pit mining)
Extracted in fairly pure form
activities related to mining, performed especially in the coal storage area, where
almost one-third of the whole measured quantity is recorded.
3.2.2 Ferrous and Non-ferrous Ore Extraction
Table 3.3 provides a synthetic presentation of the current mining techniques
employed in the extraction of metals and minerals [ 23 ].
Iron ore is extracted both by surface and underground mining. The most impor-
tant surface mining facilities are in South America (Bolivia and Brazil in particu-
lar), Western Australia, China, India, Ukraine and Canada. In the past years, these
countries have replaced other countries with traditional iron ore mining on the
market, such as France, Sweden or Germany. The most important iron ore deposit is
at El Mut
un, in Bolivia, with an estimated amount of 40 billion tons of iron ore, of
which over 50 % is made of magnetite (Fe 3 O 4 ) and hematite (Fe 2 O 3 )[ 24 ]. Pyrite
(FeS 2 ) is another mineral with significant
industrial applications in iron and
sulphuric acid production.
After extraction and crushing (and roasting, in case of pyrite) and before the
metallurgic process starts, ore concentration occurs through sinterisation, produc-
ing a porous conglomerate which is essential for furnace processing, because it
allows air circulation [ 25 ].
PM determination in an Indian open-pit mining facility [ 26 ] has provided the
following PM 2.5 values (Fig. 3.5 ).
Logically, the highest concentrations of PM (about 20
g/Nm 3 ) were measured
in point A1, corresponding to the office building of the mining facility, and point
μ
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