Environmental Engineering Reference
In-Depth Information
Water content (%):
W
W
w
w
100(%)
(19.7)
S
(may also defined as W
W
/(W
W
W
S
) by some metallurgists).
% Solids:
W 100
WW
1
1w
(%)
S
P
(19.8)
S
W
Degree of saturation:
V
100
V
wG100
G
W
d
S
(%)
(19.9)
V
wd
To t a l unit weight:
WW
VV
G e
1e
S
W
(kN/m )
3
(19.10)
t
W
V
S
Dry unit weight:
W
VV
G
1e
S
t
3
1w
(kN/m )
(19.11)
d
W
V
S
19.2.3
Tailings properties
19.2.3.1
General
Tailings properties differ considerably depending on the ore from which they are derived,
the mineral process and whether the ore is oxidised (i.e. from weathered rock). Table 19.1
gives general characteristics of engineering behaviour.
When planning any tailings disposal project, tailings representative of the operational
process plant should be tested to determine the properties required to predict behaviour in
the storage. It should be noted that, in many cases, tailings produced from trial crushing
Table 19.1.
Summary of typical physical tailings characteristics.
Type of tailings
General characteristics
Clay and silt, high plasticity, very low density
(3)
Ultra-fine tailings, phosphatic clays, alumina
red mud
and permeability
Washery tailings, coal, bauxite some iron and
Clay and silt, medium to high plasticity,
nickel ores
medium to low density and permeability
“Oxidised”
(1)
mineral tailings, gold, copper,
Silt and clay, some sand, low to medium
lead, zinc etc.
plasticity, medium density and permeability
“Hard rock”
(2)
mineral tailings, gold, copper,
Silt and some sand, non plastic, high density,
lead, zinc etc.
medium to high permeability
Notes: (1) Ore is completely or highly weathered, or altered rock; (2) ore is slightly weathered to fresh
rock; (3) assuming no desiccation.
