Stone, Sand and Gravel REVIEW - May/June 2018 - 39
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Tailings release into active pit.
MOST OPERATIONS USE WET processes resulting in tailings, a mixture
of water and mineral particles. The operations must store this mixture
on site in ponds for a sufficient time for the mineral particles to settle
out. We refer to these ponds as tailings impoundments and tailings dams.
Design of impoundments requires specialized engineering knowledge. The
owner should consider involving a registered professional engineer with
dam design experience. The design should address these issues: foundation
suitability, construction materials, tailings production rates, precipitation
inflow and use of spillways or pumps to control the pool level, seepage and
While safe dams require good design, it is important that those performing
the construction take care in making the design a reality. Proper foundation
preparation, placement and compaction of dam material, installation of
decant pipes and spillways all play a major role in the successful completion
of the project. It is crucial that the designer's construction plans be followed and that the designer is consulted if field conditions differ from plan.
During the design process, an operations manual should be written to
govern how the impoundment is operated. Regular inspection should be
conducted by qualified personnel during construction as well as operation to
confirm the dam's continued adequacy. Inspections should also be performed
after extreme precipitation and earthquakes. As long as the impoundment
has the ability to impound water, it must be regularly inspected.
Get more details at www.msha.gov.
STONE, SAND & GRAVEL REVIEW, www.nssga.org 39