7
As shown in Figure 9, the fractures located within the
caved zone and above the panel edges experience the larg-
est increase in aperture. In contrast, the horizontal stresses
induced by mining reduce the aperture of subvertical frac-
tures at the middle of the panels.
Figure 10 shows the aperture plots for bedding plane
permeabilities. Bedding plane separation can be seen in the
area above each panel but is pronounced above the panel
edges and in the caving zone. The lowest aperture values are
within the area above the pillars from mine level to 150 m
above the roof.
Figure 11 shows the aperture plots for permeabilities of
both sub-vertical fractures and bedding planes. The aper-
ture distribution is mainly dictated by bedding planes as
they correspond to the larger aperture values. The area with
lowest aperture values is still above the pillars but is shrunk
to 120 m above the mine.
Permeability Calculation
Rockmass permeability is mostly controlled by the permea-
bility of fractures due to the typically low permeability of the
rock matrix. So, it is assumed the rock matrix permeability
Figure 9. 3DEC results on the aperture values in mm for subvertical fractures (a) after mining the first panel (b) after mining
the second panel (c) after mining the third panel
As shown in Figure 9, the fractures located within the
caved zone and above the panel edges experience the larg-
est increase in aperture. In contrast, the horizontal stresses
induced by mining reduce the aperture of subvertical frac-
tures at the middle of the panels.
Figure 10 shows the aperture plots for bedding plane
permeabilities. Bedding plane separation can be seen in the
area above each panel but is pronounced above the panel
edges and in the caving zone. The lowest aperture values are
within the area above the pillars from mine level to 150 m
above the roof.
Figure 11 shows the aperture plots for permeabilities of
both sub-vertical fractures and bedding planes. The aper-
ture distribution is mainly dictated by bedding planes as
they correspond to the larger aperture values. The area with
lowest aperture values is still above the pillars but is shrunk
to 120 m above the mine.
Permeability Calculation
Rockmass permeability is mostly controlled by the permea-
bility of fractures due to the typically low permeability of the
rock matrix. So, it is assumed the rock matrix permeability
Figure 9. 3DEC results on the aperture values in mm for subvertical fractures (a) after mining the first panel (b) after mining
the second panel (c) after mining the third panel