Environmental Engineering Reference
In-Depth Information
F i g . 4 Mine tailings ( a ) schematic dry cover, ( b ) zinc mine waste dry cover, ( c ) schematic wet cover, ( d ) zinc mine
waste in covered with water, Padaeng zinc mine
barrier against oxygen, the material must have a
high capability to keep water, with the ability to
consume oxygen consisting of an organic material,
such as sewage sludge or paper mill sludge.
is a list of recommendations for using vegetation
mats as bioengineering materials:
• To anchor perennial solid binding grass mats
to a slope, mats can be cut to form any shape
desired. A shallow, narrow trench built along
the contour of a slope and planted with a veg-
etation mat may become an effective terrace.
• The mat should remain attached to stable veg-
etation and thus be held in place from the top.
The mat can be pegged to prevent ripping and
sliding. This technique would be used to stabi-
lize the contaminated soil.
• Vegetation mats can be used as building
bricks. Slice the mats into rectangular pieces
and use them to construct a very steep, living
wall. The bricks can be pegged to each other
and to the underlying substrate. This tech-
nique may be useful around culverts or sunken
walkways and control erosion.
In Australia, Vetiveria zizanioides has been
successfully used to stabilize mining overburden
and highly saline, sodic, magnesic, and alkaline
(pH 9.5) tailings of coal mines, as well as highly
acidic (pH 2.7) and arsenic (As) tailings of gold
mines. In China, it has been demonstrated that
2.1.2 Wet Covers
The tailings are fl ushed into water body with a
water column over and above the mine waste.
The depth of the water column must be adequate
to avoid oxidation. Preferably the wet cover
treatment is established on fresh tailings that are
not yet oxidized. Flooding of pre-oxidized tailings
must be avoided in order to prevent the release of
metals (Fig. 4c, d ) (Demers et al. 2008 ; Holmström
and Öhlander 2001 ; Macías et al. 2012 ).
2.2
Sodding
It is a bioengineering technique that uses
vegetation mats for mine soil stabilization and
erosion control. This technique has been used
with success with a variety of grasses (Fig. 5 ).
Perennial grasses with sturdy adventitious root
mat anchor and stabilize mine soils. The following
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