PASTE & TAILINGS 2020
Dry stack tailings to tailings pumps upgrades
Paterson & Cooke outlines its view on filtered dry stack
tailings including a European mine example
Mineco Olovo lead mine filtered tailings
discharge during commissioning
Recent high-profile tailings facility failures,
in addition to the ever-increasing water
stress associated with the mining
industry continues to motivate improved
management of water quality and quantity
across the whole mining production platform.
The concept of filtered dry stack tailings has
long been discussed but historically there has
been a relatively slow uptake in this technology
with cost being a principle constraint. However,
the cost balance is shifting with the increased
value in water recovery and alternative tailings
disposal options. In tandem with this,
technological improvements resulting is
significantly larger capacity filters, coupled with
a growing legislative and stakeholder
requirements for the demonstration of best
practice are motivating an increase in filtered
tailings applications.
Investing in fundamental research to
understand the material properties of dewatered
tailings and incorporating these
technologies in new projects has been key to
the growth of this market segment for Paterson
& Cooke. “We have extended our global
network of laboratories through which we
routinely conduct de-watering test work and
investigations on the preparation and
placement of filtered dry stack options as an
alternative to high density paste/thickened
tailings pumping. We have found that the rising
cost of power in many countries and the
increased scarcity, and importance, of water has
meant that the gap between the total cost of
ownership between paste and filtered solutions
is decreasing.”
Paterson & Cooke recently designed and
commissioned a dewatering preparation plant in
Europe that produces filtered tailings at <12%
moisture content that is deposited on a dry
stack. This is Mineco’s Olovo cerussite lead ore
mine in Bosnia, were the attached photo shows
filtered tailings discharge during
commissioning.
“We are also identifying the opportunities
associated with combining filtration for both dry
stack tailings disposal and high-density paste
backfill within the same plant, allowing
functional duality and a relative cost saving
compared to the individual system costs.
Indeed, it has been our experience then one of
these functions may be a mandatory project
requirement, but by its inclusion the
opportunity to leverage the other from it
becomes economically viable. This combination
of tailings dewatering function can offer
multiple platform benefits across a site, but its
impact on water recovery and surface tailings
disposal is often most significant. The ability to
return tailings below ground, couple with dry
stack placement allows for a considerable
smaller surface footprint and associated
impact.”
In looking to minimise water consumption
and the environmental impact of tailings
facilities Paterson & Cooke believes that it is
also vital that mining operations explore minewide
opportunities to reduce their operational
footprint. This means continually evaluating
new mining techniques and process
technologies. “We have done numerous
evaluations for the hydraulic hoisting of ore
from underground using pressure exchange or
high pressure pumping systems. In existing
mines this provides opportunities to increase
mining rates beyond the shaft hoisting capacity,
or for new mines, eliminating or perhaps
reducing the shaft dimensions and thus
increasing the rate at which the shaft can be
sunk and shortening the time to begin
production. Hydraulic hoisting requires a supply
of water from surface in a pressure exchange
system, however, using a high pressure slurry
pump underground to hoist the ore-slurry can
use ground water and reduce the mine
dewatering pumping requirements. When
considering options for the efficient use of
available water a holistic view of the
technologies available provides valuable
insights into where water savings can be
achieved.” IM
The Olovo concession was acquired by Mineco in 2012 and received in 2018 the first new Exploitation
Licence to be issued in Bosnia & Herzegovina in over 30 years. The target production is 120,000 t/y
of cerussite lead ore. Hot commissioning of the processing plant was achieved in August 2019
P4 International Mining | SEPTEMBER 2020 Supplement