Environmental Engineering Reference
In-Depth Information
Fig. 3.5 PM
2.5
monthly
averages in Baliparbat-
Daitari, India
70
60
50
Max.
Min
Avg.
CPCB Standards
(24hrly)
40
30
20
10
0
A1
A2
A3
A4
A5
A6
A3, near the OMC (the company that took the measurements) office building.
However, similar concentrations were measured outside the mining facility, in
various places of local social activity, which indicates that nanoparticles do no
show sedimentation tendencies.
The amounts of metallic copper found in nature cannot cover the market
demand. Therefore, it is exploited by mining and successive industrial processing.
The most important copper ores are copper matte CuO(OH), cuprite Cu
2
O, tenorite
CuO, algodonite Cu
6
As, paramelaconite (Cu
+
Cu
2+
)
2
O
3
and chalcocite or copper
pyrite CuS.
A long-term study on PM emissions in copper mining facilities provides relevant
results in the field (Table
3.4
)[
27
]. For these emissions, it is easy to notice a general
decreasing tendency in the concentrations of all indicators characterising PM,
which may be the consequence of both technological improvement along the past
two decades and the state-of-the-art monitoring equipment, besides the specific
legal limitations. PM
2.5
variations along the years—an increase of the initial value
followed by a constant decrease towards the end of the studied period—may be
the result of the intensive/extensive copper ore extraction activity depending on
the metal demand on the market.
Studies similar to those conducted for copper extraction in India were carried out
for a chromite mine belonging to the same company. The PM
10
values were
between 65-85
g/Nm
3
in Bangur,
a locality near the quarry [
28
]. Although within the admitted range, most of these
values are closer to the upper limit. The most important chromite ores, used almost
exclusively for chromium production, are the chromite (FeCr
2
O
4
) and the crocoite
PbCrO
4
[
29
].
A comparison of the values recorded for chromite ore excavation (Table
3.5
)
with those recorded within the iron ore quarry (Table
3.6
) will show that the former
are higher without exception. This means that either the excavation tools crush the
rocks into finer particles or the chromite mining facility is at a much lower altitude
than the iron mining facility, and since there are no air currents to spread the PM,
they accumulate in the extraction caldera. Such tendencies are also present in
countries that use advanced technologies in surface mining [
30
].
g/Nm
3
within the quarry perimeter and 45-76
μ
μ
