Environmental Engineering Reference
In-Depth Information
F i g . 2
Knowledge explosion in mine waste reclamation (Data gleaned from
www.sciencedirect.com
with keyword
“mine reclamation”)
and transported to different places with the wind
or leached with water. If the metal-rich parent
rocks consist of iron- and sulfur-containing min-
eral pyrite, this sand is often rich in sulfur that by
reaction with oxygen and water is transformed to
sulfuric acid. Thus, the tailings are subjected to
chemical weathering process leading to the for-
mation of acidic mine drainage in which heavy
metals easily dissolve. To avoid leakage of heavy
metals, the mine residue needs to be covered with
a material that prevents penetration of oxygen.
There has been knowledge explosion in mine
waste reclamation (Fig.
2
) (Li
2006
). A relatively
cheap method is to cover the tailings with water;
however, this method demands barriers that must
be carefully maintained to avoid the risk of broken
walls and thereby contamination of the surround-
ings. Therefore, many mine tailing impoundments
are instead covered with a dry material (back
fi lling from mine source). In restoration of mine
areas, the establishment of vegetation is very
important, not only for giving the landscape a
natural appearance but also for stabilization of the
cover material (Wong
2003
; Zornoza et al.
2012
).
Environmental implications of mine waste:
(a) Threat to biodiversity
(b) Generate acid drainage
(c) Food safety in the vicinity of mine
(d) Threat to national heritage
(e) Increase
environmental
pollution
in
soil,
water, and air
2
Ecological Restoration
of Mine Wastes
Various unit operations of “ecological restoration
of mine waste” are shown in Fig.
3
. A layer of
vegetation can prevent both physical erosion and
leaching of heavy metals.
2.1
Covering Techniques
Weathering of mine tailings can be prevented by
a minimized contact with air, which can be done
by covering the tailings with either water (wet
cover) or a dry substrate (dry cover).
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