Can alternative tailings disposal become the norm in mining?
There is no doubt that the resources extracted from mining
are critical to our way of life. Likely, you’re reading this on your
computer, smartphone, or tablet. Mining touches all our lives
daily (in addition to metals used in electronics, think about that
can of soda you are drinking, or the aggregate used to pave your
driveway). The industry works hard to make sure the net impact
is positive.
However, the waste associated with mining, both past and
present, is an unavoidable result of conventional mineral
processing. In the future it may be possible to extract metals like
copper and gold without crushing and grinding the ore down to
fine particle size and adding considerable quantities of liquid,
resulting in conventional tailings.
What are the challenges associated with conventional
tailings? Well, it is all about water. Managing seepage from the
tailings themselves, monitoring pore water pressure within the
tailings dams or designing facilities to safely store or pass flood
events. Because such a significant quantity of water is added
during mineral processing, “conventional” tailings dams store the
tailings as a slurry. Water within the tailing material is either
evaporated, migrates as seepage or remains entrained within the
tailings impoundment. Removing water prior to disposal through
various means is considered “alternative” disposal. Mining low
grades of ore has resulted in increased water use per unit of
production. In some cases, the availability of water is one of the
greatest constraints on mine development.
Internet: <www.stantec.com> (adapted).