Geoscience Reference
In-Depth Information
According to the results, the saturated permeability coefficients obtained for the
ROM WR, at the different dry densities resulting from the imposed vertical stresses,
are the same. For the leached waste rock, on the other hand, these results clearly
show a lower saturated permeability coefficient as the vertical stress, or the
equivalent overburden height of the dump, increases.
These results are particularly interesting in light of the influence of the waste
rock characteristics and its initial grain size distribution on the evolution of the
coefficient of permeability with the imposed vertical stress (resulting density).
% passing
< sieve # 4
ASTM mesh
% passing
< sieve # 200
ASTM mesh
Vertical
stress
σ
v
'
(MPa)
d
60
(mm)
d
10
(mm)
d
60 /
d
10
Material
Initial
After
test
Initial
After
test
Initial
After
test
Initial
After
test
Initial
After
test
72.8
4
9.3
1.9
5.7
13
ROM
waste
rock
7.7
1.8
90.6
10.0
9
8
11.3
1.9
63.3
3.9
16
56.9
12
13.9
2.4
2.3
25
38.2
4
16.2
3.4
1.2
32
Leached
waste
rock
34.6
8
11.3
20.3
2.9
4.6
46.5
2.9
0.6
16
41
31.5
12
22.8
4.8
0.6
53
Table 4.3.
Grain size distributions before and after oedometric tests
Maximum vertical
stress. σ
v
' (MPa)
Dry density
γ
d
(kN/m
3
)
Saturated permeability
coefficient k
s
(cm/s)
Material
5·10
-1
4
20.6
3·10
-1
ROM waste rock
8
21.2
3·10
-1
12
22.0
2·10
-1
4
21.1
Leached waste
rock
5·10
-2
8
21.8
1·10
-2
12
22.6
Table 4.4.
Saturated permeability coefficient under constant vertical stress
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