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considerations, local regulations, consideration of the local hydrological and seismic
conditions, as well as the geographical and geotechnical conditions.
Published papers and a book about site selection methods include Robinson et al
(1980), who provide a qualitative and semi-quantitative method; Robinson and Moss
(1981) describe the use of these methods for several mill sites, while Keeney (1980)
deals with site selection for power plants and other civil works. A successful example
of the site selection process for mine facilities has been documented by Crouch and
Poulter (1983). Comprehensive coverage of site selection and site investigation has
been given by Clayton et al (1982).
Consideration of the position for a new impoundment must take account of the risk
of damage to life, property and the environment should failure occur both during
operation and after closure. It could be argued that the site for the tailings dams at
Stava, Incident No 117, had been badly chosen in view of the vulnerability of the
downstream town and hotels. The Merriespruit tailings dam, Incident No.202, had
been sited very close to an existing township on ground sloping down into the town,
apparently with no regard to the risk it imposed.
Tailings can usually be transported over considerable distances relatively cheaply,
so that the choice of site may not be as limited as might at first appear to be the case.
This can result in greater freedom to select a site which is relatively free of constrains
and where the consequences of failure can be reduced considerably. There may also
be benefits to the mining operation as a whole and not just to that element related to
tailings disposal.
Example. As an example, rock containing copper is mined high in the Andes in
Chile, and many mines crushed, ground and processed this ore near the mine.
Lorries brought the copper concentrate down the narrow mountain tracks, distances
exceeding 160 km to smelters or for export. In winter they could be held up for long
periods. The narrow, steep sided valleys near the mines were used for the
impoundments, but fairly high dams were needed for the storage of appreciable
volumes of tailings, and there was a growing risk of downstream damage if the dams
should fail. Much better sites for large impoundments could be found on the flatter
land at the foot of the Andes where the rainfall was less and the rate of evaporation
greater than in the mountains. In some cases low hills could be joined by tailings dams
to enclose large areas.
The ore was still crushed and ground at the mine, ready for processing, but was
then carried by pipeline or concrete flumes, distances exceeding 80 km, down to the
flatter land, where the processing plant was constructed adjacent to the site for the
impoundment. In this way the distance that the concentrate had to be carried was
greatly reduced, could be continued though the winter, and tailings storage was
greatly simplified, with provision for much greater storage than had been possible
adjacent to the mines. The better climate at the lower levels was also an advantage
for the construction of the tailings dams.
Example. At the McLaughlin mine in North America, the processing plant and
tailings impoundment were sited approximately 7 km from the mine. This was done so
that the tailings impoundment was in a location with favourable topography and
founded on clayey subsoils for tailings solution containment. The ore was crushed