Page 461 - Rock Mechanics For Underground Mining

LONGWALL COAL MINING

Figure 15.9 Modelled vertical abut-
ment stress relative to the goaf edge,
Gordonstone Mine, Queensland, Aus-
tralia (after Kelly et al., 1996).

Similar effects to those just described have been recorded at a number of other
Australian collieries. Figure 15.10 shows the results of FLAC3D computations of
the vertical stresses developed around four adjacent longwall panels at a depth of
500 m at the Appin Colliery, New South Wales, Australia. It will be noted that the
peak abutment stress at the ends of the panels is about twice the overburden stress.
The maximum vertical stress of about three times overburden stress occurs not at
the corners of the panels as in Figure 15.8 but over the pillars between mined-out
panels.
Thediscussionsofarhasconcentratedonthedistributionofverticalstressesaround,
firstly, a single longwall panel, and then a group of adjacent panels. However, the
redistribution of the horizontal in situ stresses during and following mining must not

Figure 15.10 Vertical stress profile
for LW25–LW28a, Appin Colliery,
New South Wales, Australia (after
Kelly et al., 2002).
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