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structure is not dependent upon the strength of the coarse tailings as a foundation (US EPA,
1994).
Tailings water
Added dyke
Added dyke
Coarse tailings
Starter dam
Figure A.2: Downstream construction method
The centreline construction method is similar to both the upstream and downstream methods,
however sequential raising takes place in a vertical direction and the centreline does not move
beyond local, short-term, deviations during non-symmetrical placing of material. The
Australian Government LPSDP (2007) states that the centreline method is not commonly used
in Australia as it is unsuitable for long-term storage.
Tailings water
Added
dyke
Added
dyke
Addeddyke
dyke
Added
Coarse tailings
Starter dam
Toe
Figure A.3: Centreline construction method
Stability analyses of tailings dams differ from those used for the analysis of conventional
dams as a result of the staged construction methods used for tailings storage facilities
(ANCOLD, 2012). Conventional water retention dams are built to their full design capacity
prior to the dam’s operation and use essentially one construction method – downstream
(Chambers, 2012). Whereas tailings dams are designed and constructed in stages coinciding
with the operation of the mine. Therefore it is important to understand the implications of
consolidation and rate of construction for upstream, downstream, and centreline construction
methods during their stability analysis. Tailings dams also differ to water retention dams in
that the design life for tailings dams is much longer (perpetuity) compared to the finite life of
water supply dams (Chambers, 2012). The construction sequence is also important in
determining what loading conditions should be used in the stability analysis. The loading
conditions are either short-term, assuming the embankment has just been constructed, or longterm after consolidation has occurred (see Section 3.1).
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