A OPEN PIT MINING AÇIK OCAK MADENCİLİĞİ

23 rd
Table 1. Geotechnical characteristics of
different rock formations.
Properties Quaternary Limestone Phosphate Marl
Uniaxial
Compressive
strength
(MPa)
Angle of
internal
friction (°)
Rock
cohesion
(MPa)
Specific
gravity
(KPa)
Young's
modulus
(MPa)
Poisson's
ratio
19.17 58.84 22.55 21
25 40 37 15
1.96 8.24 7.35 1
18 25.5 22.55 20
5000 27000 24000 1000
0.32 0.25 0.28 0.40
3.3 Effect of Topography
For the case of the landslide of Kef
Essenoun, the sliding mass presents wrinkles
resulting from the side spreading out. The
effect of the topography on the mobility of
the sliding mass is weak in this case. The
effects of the seismicity and pluviometry are
weak because this zone is arid and
characterized by a weak seismic activity
(Figure 5).
Figure 6. Kef Essenoun open pit before the
landslide
The bench represented in red squares has a
rather good stability and the safety factor is
around 1.3, for a slope angle equalizes with
75°, for a critical condition of slope angle
which exceeds the 80° the safety factor is
around 1.0 (Figure 7). It is worth noted that
the overall slope of the open pit is in a
critical condition. But if the height and the
angle of the bench are taken equal to 15 m
and 55° successively with a bench width
equal to 15 m there will be an overall slope
of the pit characterized by 70 m height and
an overall slope angle of 30° from where the
safety factor will be higher than 2.
Figure 5. Topographic constraint visualized
by the form of the corridor of displacement
3.4 Effect of the Geometry
The bench of Kef Essenoun open pit is
characterized by 30 m height, an angle of
slope of 75° and sometimes it exceeds the
80° and a bench width equal to 10 m (Figure
6).
Figure 7. The safety factor according to the
height and the angle of slope.
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