1. L
atin America, particularly Chile, Peru and
Bolivia is often cited as the frontline in
mining water management. This is due to a
combination of the level of mining activity plus
also the size and arid nature of the Atacama
Desert region that covers so many mining
operations, from obviously copper but also
lithium, gold and other metals. The Atacama
aside, there are also the operations not formally
thought of as being in that region but being very
high altitude also have issue with water
sourcing.
According to a recent Reuters report, Chile’s
copper industry alone will triple its use of sea
water for industrial processes in the next
decade, state copper agency Cochilco was
quoted as saying on January 8, as miners in the
world’s top producer of the red metal seek
alternatives amid growing water shortages.
Cochilco said in the cited report that it expected
use of sea water, both desalinated and direct
from the ocean, to increase by 230% over 2018
levels.
Chile’s top miners, including BHP, Anglo
American, Glencore and Antofagasta, are
primarily concentrated in the northern half of
Chile, the arid Atacama desert region that is
among the driest on earth. Sea water could
satisfy 43% of the miner’s demands by 2029,
Cochilco said in the report. “More and more
miners are building their own desalination
plants or using water straight from the ocean to
confront shortages of water,” the report said.
Only last year, in April, a ceremony took place
today at Puerto Coloso, Antofagasta, where
Minera Escondida inaugurated a 2,500-l/s
desalination plant to supply the mine’s needs.
The new plant is in addition to the company’s
525-l/s plant, which has been in operation for
12 years.
The new plant is at the heart of the
company’s water strategy, which consists in
increasing the use of desalinated water and
recovering more water from its processes as a
means of gradually reducing withdrawals from
aquifers.
Construction of the plant required an
investment of $3.43 billion. This included two
42” pipelines to transport the water to 3,200 m
above sea level, four high-pressure pumping
stations, a reservoir at the mine and high-
voltage electricity infrastructure to operate the
system.
In order to ensure the electricity for pumping
the water, BHP awarded a long-term contract for
the development of the Kelar Power Plant,
which was originally designed to use coal but
was converted into a combined-cycle natural
gas plant in order to have energy from a cleaner
source.
“The plant we are inaugurating today
required 45 million man-hours of work, a
challenge that was notable for an outstanding
performance on safety, our most prized value,”
said Mauro Neves, President of Minera
Escondida at the time. “At present,” he added,
“we are operating three concentrators
simultaneously, an unprecedented situation in
the mining world, giving us a greater processing
capacity with which to maintain our copper
output. In this, the new desalination plant plays
a crucial role.”
Daniel Malchuk, President of BHP Minerals
Americas, indicated that “this plant reflects our
deeply held belief that it is possible to practice
sustainable mining, which is both an ethical
imperative and a fundamental condition for the
business. In Chile, we aspire to cease using
fresh water altogether as from 2030. We have
progressed in this transition and will continue to
do so gradually over the next ten years.”
Solar powering desalination
Back in June 2018, TRENDS Industrial and Almar
Water Solutions signed a Memorandum of
Understanding (MoU) to collaborate on the
development of a huge solar powered
desalination project for the Atacama region in
Chile, including the mining industry: Energias y
Aguas del Pacifico or ENAPAC. Almar has
become an equity investor in the project and the
MoU specifies a further Joint Development
Agreement for the completion of ENAPAC, one of
the largest solar powered desalination projects
in the world.
Rodrigo Silva, TRENDS Industrial’s CEO, and
Carlos Cosín, Almar Water Solutions CEO, sealed
the agreement committing to seek the economic
46 International Mining | MARCH 2019
Go with the flow
Water management from the largest desalination plants,
to dry stacked tailings technology: solutions for sourcing,
saving and reusing water are vital to future mining,
reports Paul Moore
WATER MANAGEMENT
Last year Minera Escondida, majority owned by
BHP, inaugurated a 2,500-l/s desalination plant
to supply the mine’s needs
2. 48 International Mining | MARCH 2019
WATER MANAGEMENT
and technical concretion of the project, through
the strategic partnership of both companies. On
the MoU, Rodrigo Silva stated that is
consolidates the work of several years “in which
we have developed a sustainable project from
the socio-environmental point of view, as well as
from the economic perspective for the
advantages of the multiclient model of ENAPAC,
in which economies of scale are taken advantage
of,” while reduces the impact on the territory and
improves efficiency, “as we have been seeing in
large-scale mining projects in Chile, which have
opted for collaboration.”
Produced water will be pumped 45 miles and
across a height of 700 m to a new reservoir in
Copiapó, near the Tierra Amarillo mountains,
where mining companies operate. The system
comprises five pumping stations, one at the
intake, one at the treatment plant, two on the
piping route, and one at the reservoir.
On the relevance of the signed agreement,
Carlos Cosín assured that “this alliance
consolidates Almar’s interest in developing
innovative and state-of-the-art technology
projects combining desalination with solar
energy, while at the same time sealing our
commitment to the long-term success of the
ENAPAC project, particularly with its potential
clients to whom we can ensure the reliability of
the water supply, which is so urgently needed in
Atacama and for which we hope that ENAPAC will
help alleviate, in part, the severe water scarcity
in the region”.
The ENAPAC project is part of the list managed
by the Office of Management of Sustainable
Projects of the Chilean Government Ministry of
Economy and, therefore, both executives visited
the Chilean Economy Minister, José Ramón
Valente, and his team to present the state of
progress of the project and the credentials of the
companies that will develop the initiative.
ENAPAC consists of a seawater desalination
project for Atacama that will be supplied with its
own source of photovoltaic energy. With an
estimated initial investment of $500 million
ENAPAC will become the largest desalination
plant in Chile and Latin America, for its maximum
capacity of 2,600 l/s, and will also be the first
multiclient, the only large-scale solar powered
(100 MW) and one of the most advanced projects
in the world with a combination of reverse
osmosis desalination and photovoltaic energy.
The planned water reservoir has a 600,000 m³
capacity.
IDE gets QB2 desalination contract
IDE Technologies, a leader in water treatment
solutions, has announced that it has been
chosen by Teck Resources to design and supply
the desalination plant for the Quebrada Blanca
Phase 2 (QB2) copper mining project in Chile.
QB2 is an extension of Teck’s existing Quebrada
Blanca operation in Chile. The desalination plant
will be located at the port site for the QB2 copper
mine in the Tarapacá region and will be the
second largest seawater desalination plant in
Chile.
“IDE’s experience encompasses more than 400
desalination plants worldwide, with more than
20 successfully operating desalination plants in
Chile. The new SWRO desalination plant for the
QB2 project will produce high-quality water for
use in the copper concentrator. IDE’s design of
the QB2 desalination plant will be in accordance
with the stringent environmental requirements
and safety regulations in Chile.”
“IDE’s experience in South America and
worldwide, and their commitment to high
environmental standards were key factors in
their selection for the QB2 project,” said Karl
Hroza, Project Director, QB2, Teck.
IDE has extensive experience designing large-
scale modular RO plants for the mining sector
and is aware of the common practices and the
challenges facing the mining industry. IDE’s
modular solution simplifies the installation of the
plant while reducing installation and startup time
and cost. IDE will work closely with Teck to
ensure that the QB2 desalination plant meets its
availability and reliability goals.
“We’re excited to partner with Teck in
providing high-quality water in an economical
and sustainable manner, to support the
expansion of this mine,” said Guy Sagie, CEO,
IDE Projects. “Our modular SWRO desalination
design is an excellent solution for remote
locations due to the use of prefabricated
modules with minimal maintenance
requirements. Once completed, the QB2
desalination plant will deliver a consistent and
reliable supply of water for daily mining
operations.”
New horizons with filtered tailings
With the Vale Brumadinho tailings disaster in
Brazil, alternative options to large conventional
tailings dams are on everyone’s mind. Tailings
are a fact of life on a mine site and as most in the
industry know are pumped as a slurry and stored
in large tailings storage facility (TSF). The slurry
is a mixture of process water and the solid
tailings itself. To hold the water and solids in the
TSF area, large tailings dams are generally
required to enclose the area. The tailings will
eventually form a tailings beach and the process
water will accumulate in the low point of the TSF
area forming a tailings pond. Water from the
tailings pond is typically recirculated back to the
mill for re-use. If there is an excess of process
water, it is treated and pumped to the
environment.
But as SNC-Lavalin told IM: “There are certain
key disadvantages of a traditional TSF. The TSF
typically occupies a very large surface area. Any
rain or snow that falls within this area comes into
contact with the tailings and as such is
considered as ‘contact water.’ Consequently, the
volume of water to manage increases as the size
of the TSF increases. Furthermore, it is critical to
manage the water level in the TSF area. Poor
water management in the TSF area can lead to
high water level against the tailings dam, which
could impact its structural stability and lead to
catastrophic failure if no remedial action is taken.
The tailings form beaches that are exposed to
the elements (rain and air). If the tailings are
Potentially Acid Generating (PAG), they can start
to oxidise and release heavy metals into the
water, such as iron, nickel and copper.
Consequently, additional water treatment will be
required to remove these heavy metals prior to
discharge to the environment.”
In order to minimise these risks, new mine
operations being developed are considering the
use of Filtered Tailings (often called dry
Back in June 2018, TRENDS Industrial and
Almar Water Solutions signed a Memorandum
of Understanding (MoU) to collaborate on the
development of a huge solar powered
desalination project for the Atacama region in
Chile, including the mining industry: Energias
y Aguas del Pacifico or ENAPAC
3. 50 International Mining | MARCH 2019
WATER MANAGEMENT
stacking). This approach involves the dewatering
of the tailings in order to manage it a filtered
tailings solid instead of a liquid slurry. Some of
the advantages of this approach as summarised
by SNC-Lavalin are:
n No tailings dam required to store tailings and
process water and therefore no risk of dam
failure
n High process water reuse rate in the mill;
n Significant risk reduction of leaks or spillage
(ex. damaged pipes) to the environment
n Filtered tailings can be compacted and/or
levelled once disposed on the dedicated pile;
n Filtered tailings are geotechnically stable and
can be stockpiled at greater height and with
steeper slopes than conventional tailings,
therefore reducing the total surface footprint
required to store the tailings;
n Filtered tailings can be progressively
revegetated, ie before mine closure, as the
mine is still in operation.
SNC-Lavalin is involved in the design and
operation of filtered tailings deposition at several
mine sites. One project in particular is the
tailings storage facility at Goldcorp’s Eleonore
mine site. SNC-Lavalin was involved in the design
of the filtered tailings storage area from the start
of the project through its construction and
implementation, and is currently involved in the
design of its expansion.
The slurry is dewatered using large filter
presses to produce a filtered tailings with a
typical moisture between 15 to 20% w/w. The
filtered tailings are then transported to the
tailings storage facility by haul truck. The filtered
tailings are deposited onto the tailings pad which
is covered with a geomembrane to protect
against any groundwater infiltration.
The tailings storage facility occupies an area of
80 hectares, divided into four cells. Currently, the
first cell is being used. Once it has reached its
storage capacity, tailings will be deposited in the
second cell while the first cell will undergo
progressive restoration. Surface runoff from rain
and snowmelt are collected and transferred to a
collection pond. The water is then pumped to the
water treatment plant where it is treated and
then re-used in the process plant. Excess treated
water is also discharged to the environment.
The co-disposal option
SNC-Lavalin is also involved in the design of co-
disposal storage facilities which involves the co-
disposal of waste rock and filtered tailings. The
co-disposal strategy is to use waste rock to
construct peripheral berms and peripheral roads.
Central access roads within the storage facility
are also needed to act as a filtering berm to
ensure proper drainage of the co-disposal
storage facility. Berm construction will be
managed to confine the tailings surrounded by
waste rock.
Advantages of this approach over dry stacking
alone includes significant reduction of the
surface footprint required for a given mine site
since the waste rocks and tailings are stored
within the same footprint. The overall footprint of
the tailings storage area could typically be
reduced by 20 to 25% when compared to
conventional slurry tailing deposition.
If the filtered tailings and waste rock are PAG,
it can be progressively encapsulated with a Non-
Acid Generating (NAG) filtered tailings and waste
rocks to reduce the risk of its oxidation by
increasing the degree of water saturation in the
PAG tailings, limiting air diffusion and thus
reaction of sulphide materials. The co-disposal
approach can also be implemented in the open
pit once it is decommissioned.
FLSmidth and EcoTails™
Dry stack tailings can recirculate up to 95% of
mine process water and eliminates the risks of
catastrophic tailings flow when a dam fails. The
concept is not new but in recent years, FLSmidth
has put significant efforts into improving the
technology to make it commercially viable. Part
of the R&D took place in cooperation with
already mentioned Goldcorp, where Goldcorp
and FLSmidth have co-developed the EcoTails™
filter technology. This is a process which blends
filtered tailings with waste rock, creating a
geotechnically stable waste product and
eliminating the need to keep conventional slurry
tailings contained in a dam and submerged in
water. The resulting environmental benefits are:
no tailings dam, lower fresh water use, reduced
acid rock drainage, a smaller mine footprint, and
less overall risk. The EcoTails™ R&D project is in
the feasibility testing phase. The next stage is a
demonstration scale project.
In addition to the co-development project with
Goldcorp, FLSmidth says it is continuously
working to improve its filter technology, and in
2018, it sold three filtered tailings projects and
three of the world’s largest paste thickeners.
Teck reports major saturated rockfill
potential
Teck Resources says the results from a saturated
rock fill (SRF) project at its Elkview coal
operations in British Columbia, Canada, show the
technology has the potential to replace future
active water treatment facilities (AWTF) and,
further, reduce capital and operating costs for
water treatment. In 2018, the company
successfully operated its first SRF project at
Elkview, which has now been working for the
past 12 months and “is demonstrating near-
complete removal of nitrate and selenium from
the feed water,” Teck reported in its 2018
financial results.
With the full-scale trial showing promising
results, Teck is working to increase the capacity
of the Elkview SRF to potentially reduce reliance
on active water treatment, it said. This approach
has not yet received the necessary approvals and
Teck said it continues to progress the
construction of additional AWTFs to comply with
the measures required by the Elk Valley Water
Quality Plan, an area-based management plan
approved in 2014 by the British Columbia
Minister of Environment.
The plan establishes short-, medium- and
long-term water quality targets for selenium,
nitrate, sulphate and cadmium to protect the
environment and human health, as well as a plan
to manage calcite formation. In accordance with
the plan, Teck has constructed and is operating
the first AWTF at West Line Creek.
In the December quarter, Teck commissioned
SNC-Lavalin is involved in the design and
operation of filtered tailings deposition in
several mine sites including Goldcorp’s
Eleonore
4. 52 International Mining | MARCH 2019
an additional treatment step to address an issue
regarding selenium compounds in effluent from
the West Line Creek AWTF. The facility is now
operating as designed and the company has
commenced construction on its next AWTF at
Fording River Operations, which will use the
same treatment process as the modified West
Line Creek AWTF.
Teck said capital spending on water treatment
in 2019 is expected to be approximately C$235
million ($178 million), including advancing a
clean water diversion at Fording River,
application of SRF technology at Elkview,
construction of Fording River AWTF South, and
advancing management of calcite and the early
development of water treatment for Fording River
North. “This compares to approximately C$57
million of capital spending on water treatment in
2018,” Teck said.
The company continued: “In our previous
guidance, we estimated total capital spending for
water treatment between 2018 and 2022 of
C$850-900 million. We intend to complete
construction of the Fording River South AWTF,
currently under construction. If we are successful
in permitting SRF projects to replace the Elkview
AWTF and Fording River North AWTF, we estimate
that total capital spending on water treatment
during this period would reduce to C$600-650
million. If no reduction in AWTF capacity is
permitted, overall capital in the same period
would increase by approximately C$250 million
over our previous guidance, as a result of
engineering scope changes at the Elkview AWTF
and an increased volume of water treated at
Fording River North.”
Teck said it had presented regulators with
evidence that SRFs are a viable technical
alternative to active water treatment, and is
working through a review process. “We expect
that this process will result in a decision in the
first half of 2019,” it said.
In the meantime, Teck continues to advance
research and development, including the SRF
technology. “We estimate that over the longer
term, SRFs will have capital and operating costs
that are 20% and 50%, respectively, of AWTFs of
similar capacity. If we are successful in replacing
a substantial portion of active water treatment
capacity with SRFs, we believe that our long-term
operating costs associated with water treatment
could be reduced substantially,” it said, adding
that all of the foregoing estimates were
“uncertain.”
Innovations in mobile water
technologies
Mobile water treatment can play a key role in a
minesite’s overall water management strategy.
Veolia Water Technologies states: “Today,
portable solutions are able to cover emergency,
temporary or long-term water treatment needs.
Mobile units can be deployed via stand-alone
units or in combination to form complete
systems with state-of-the-art purification
technologies.”
The flexibility and cost-saving potential of
temporary mobile water treatment solutions has
encouraged growth within the industry. As an
example, Veolia Water has strengthened its
“Anytime, Anywhere” water treatment
capabilities by adding 3,000 GPM high rate filter
trailers and expanding the fleet of 1,400 GPM
ballasted clarifiers to its extensive mobile water
services fleet.
The new mobile Hydrotech™ Discfilter rentals
can operate as a filter or clarifier as it utilises
micro-screen with filter pore sizes of 10 to 100
microns. When polishing, it can handle flows of
3,000 GPM, and 2,000 GPM for clarification
applications needing chemical enhancement with
coagulants and/or flocculants. By employing
woven cloth filter elements installed on multiple
discs, and utilising an inside-out flow pattern,
this versatile gravity filter is for a variety of
applications including tertiary wastewater
filtration, water reuse, phosphorus removal,
membrane pretreatment, and stormwater
treatment.
The new units join a fleet of portable trailers,
containerised or skidded water and wastewater
treatment solutions for temporary, emergency
and long-term water treatment applications.
Current units in the fleet are Reverse Osmosis,
Actiflo® Turbo Clarifier, Filtration, Softening and
Demineralisation. Potential applications served
include physical and chemical separation for
suspended solids, turbidity, hardness and
metals; membrane separation and
demineralisation for TDS (total dissolved solids)
reduction, specialty ion exchange and heavy
metals removal.
According to Michael Reyes, Veolia Mobile
Water Services National Sales Manager, the
technologies most often deployed to mining sites
are the Actiflo Turbo clarification trailers and
Hydrex™ chemistries to support clarification,
filtration, and specialty metals precipitation. For
the mining industry, the mobile Actiflo typically
provides wastewater treatment for acid mine
drainage (AMD), tailing ponds, surface
impoundments, and seepage water.
WATER MANAGEMENT
Today, portable solutions are able to cover emergency, temporary or long-term water treatment
needs at mines
The saturated rockfill (SRF) facility at Teck’s
Elkview coal operations, commissioned a year
ago, is now achieving near-complete removal of
selenium and nitrate in 10 million litres of mine-
affected water per day
5. Actiflo® Turbo technology uses a patented
draft tube design to flocculate incoming solids
with proprietary microsand. The dense microsand
acts as a ballast as flocculation occurs,
dramatically increasing the settling rate of the
solids. This results in excellent solids/metals
separation. Hydrocyclones separate the sludge
from the microsand and recycle it back into the
unit, adding to the sustainable operation of the
unit by minimising sludge volume.
“Whether for emergencies, planned temporary
deployments or long-term rentals, mobile water
systems are becoming a reliable and effective
solution for a variety of water management
needs.”
MGX advances water treatment in the
oil sands
MGX Minerals and engineering partner PurLucid
Treatment Solutions have reported a second
deployment of an advanced wastewater
treatment system is near completion in the
Alberta oil sands and commissioning is expected
shortly. The system is capable of processing up
to 10 m³/h and will significantly reduce
greenhouse gases through energy savings on
steam generation, according to MGX.
“The technology provides superior treatment
outcomes when compared to conventional
technology which requires offsite trucking and
high cost (due to toxicity) disposal,” MGX said,
adding the technology can treat the water in line,
under temperature and pressure, without cooling
water first. This is a paradigm shift advancement
in waste water management and oil sands
operations, according to the company.
“This will result in significantly less energy
use for water treatment, reduction in greenhouse
gases and also eliminate a major operational
challenge of a steam assisted gravity drainage
facility – heat exchanger fouling.”
Mobilisation of a third system, capable of
processing 10 m³/h to extract lithium from brine,
is also being finalised, MGX said. This lithium can
be extracted by the technology once the water is
cleaned of oil and bitumen as result of the front-
end water treatment system processing.
Commencement of lithium extraction will occur
as this customer comes online.
MGX’s rapid lithium extraction technology
eliminates or greatly reduces the physical
footprint and investment in large, multi-phase,
lake-sized, lined evaporation ponds, as well as
enhances the quality of extraction and recovery
across a complex range of brines as compared
with traditional solar evaporation, the company
says.
It is applicable to petrolithium (oil and gas
wastewater), natural brine, and other brine
sources such as a lithium-rich mine and
industrial plant wastewater.
Back in August, after several successful pilot
test results, the company signed up Hatch to
advise it on the scaling up of its technology in
the western US.
PurLucid’s exclusively licensed and patented
nanoflotation technology, meanwhile, is designed
specifically for oil field environments, separating
impurities from oil and gas wastewater and
producing clean water as a final product.
Before this announcement, the two companies
reported successful commissioning of their
commercial scale 5 m³/h system.
De.mem gets Amrun water contract
Water and wastewater treatment company
De.mem says it has secured a 12-month
A$780,000 ($564,868) operations and
maintenance contract to manage potable water
and sewage treatment plants at Rio Tinto’s
Amrun bauxite mine in Queensland, Australia.
De.mem has operated the water treatment
plant at Rio’s $1.9 billion operation since 2016 on
a revolving monthly basis, with this contract,
which began in January, providing it with
business for at least a year.
De.mem CEO, Andreas Kroell, said: “This new
purchase order is another great success for
De.mem as it underlines our well established
customer base in the mining and resources
sector and our strong, recurring operations and
maintenance business.”
In December, De.mem unveiled A$350,000 in
WATER MANAGEMENT
MARCH 2019 | International Mining 53
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6. 54 International Mining | MARCH 2019
WATER MANAGEMENT
new orders from municipal and resource sector
customers, including one from South32’s
Cannington silver-lead operation in Queensland.
Rio’s investment in Amrun is aimed at
replacing production from the depleting East
Weipa mine and increasing annual bauxite
exports by around 10 Mt. Amrun, which shipped
its first bauxite late last year, is expected to
reach a full production rate of 22.8 Mt/y during
2019.
BQE Water and selenium removal
BQE Water Inc has entered into an Operating
Services Agreement with AuRico Metals Inc (a
wholly owned subsidiary of Centerra Gold Inc) for
water treatment at the Kemess mine site in
Northern British Columbia, Canada. The
treatment plant will remove heavy metals and
selenium. The selenium removal portion of the
overall treatment will utilise BQE Water’s
patented Selen-IX™ process and treat up to
6,400 m3/day of mine impacted water.
The initial term of the agreement is five years
beginning on January 1, 2020 and includes a
provision for a three year term extension subject
to satisfactory plant performance. The services
provided by BQE Water under the agreement and
the compensation received, will be similar to the
Raglan Mine water treatment agreement with
Glencore where BQE Water earns treatment fees
linked directly to the volume of water discharged
into the environment subject to effluent water
quality meeting project requirements. The
agreement follows an earlier Engineering
Services Agreement between AuRico and BQE
Water to implement the proposed treatment at
the site.
“We have been working with BQE Water for
the past three years to advance our Kemess
Underground Mine project in BC,” stated John
Fitzgerald, VP Projects & Technical Services of
Centerra Gold. “After a successful pilot program,
we received regulatory approvals for advancing
the project with Selen-IX™ as the means of
controlling selenium in environmental discharge
over the project life.”
David Kratochvil, President & CEO of BQE
Water, commented, “The signing of this
agreement represents a major milestone for us.
Not only does it increase the portfolio of plants
operated by BQE Water and will contribute
recurring revenue in North America, but crucially
it assigns the responsibility for the start-up and
operation of the first commercial scale Selen-
IX™ plant to us as the technology provider.
Based on our 14 years of operations experience
at the Raglan Mine project, we believe that this
agreement provides an excellent platform for
Centerra Gold and BQE Water to develop a long-
term relationship vested in the success of the
Kemess Underground project.”
Detailed engineering for the plant has been
issued for construction and the project is
currently in early stages of procurement and
equipment fabrication. The plant is expected to
complete commissioning by the end of 2019 with
operations beginning in 2020.
Selen-IX is a water treatment process
technology that combines ion exchange and
electro-reduction to remove selenium from large
volumes of wastewater. As a purely physico-
chemical process, Selen-IX is insensitive to water
temperature and is highly adaptable to variability
in water flows and selenium levels.
BQE Water developed Selen-IX specifically as a
non-biological method of selenium removal from
industrial wastewater to the most stringent limits
in the US and Canada without relying on dilution
in the receiving environment. The process fixes
selenium into stable refractory non-hazardous
solids suitable for co-disposal with tailings and
potential offtake by steel producers. As an
entirely non-biological process, Selen-IX does
not increase the risks of selenium bioavailability
across treatment and/or acute fish toxicity which
are real risks for biological treatment systems.
Microbial water decontamination
options
CSIRO scientists are using microbes and other
methods to remove valuable metals and other
contaminants from mine wastewater – making
remediation pay, the research company says.
And, after testing it out in the lab, CSIRO is
now working with Evolution Mining to develop
better treatment solutions for the wastewater at
the company’s Mt Rawdon gold mining operation
in Queensland.
These technologies can process water so it’s
pure enough to be safely returned to the
environment. It can also be recycled and reused
in mine production, according to CSIRO.
CSIRO’s Anna Kaksonen, who leads the
research group working in biotechnology for
water quality, said: “Certain microbes can help to
either oxidise or reduce metals or other
compounds, like sulphate, nitrate or selenate, so
we can remove them from water.
“Microbes can also be used to clean up organic
impurities and reduce acidity or alkalinity. For
example, wastewater from the alumina industry
has a lot of organic impurities that can
accumulate in the water used in ore processing.”
Biological treatment can be combined with
other processes like hydrotalcite precipitation,
delivering a more effective clean-up than either
process can alone, according to CSIRO.
The hydrotalcite (an anionic clay) precipitation
process invented by CSIRO’s Grant Douglas, and
licensed to Virtual Curtain Ltd, involves adding
patented mixture into the wastewater, which
then binds to metals and other contaminants as
it forms hydrotalcite.
BQE Water Inc has entered into an Operating Services Agreement with AuRico Metals Inc (a wholly
owned subsidiary of Centerra Gold Inc) for water treatment at the Kemess mine site
De.mem Membrane Bioreactor (MBR) and
Ultrafiltration-Reverse Osmosis (UF-RO) systems
deployed at the Rio Tinto Amrun bauxite mining
project in Queensland, Australia
7. “Contaminants are easily removed from the
wastewater as a well-settling sludge containing
valuable metals in highly concentrated
compounds. Adding biological processes after
the hydrotalcite precipitation can remove other
contaminants remaining in the water, such as
sulphate and nitrate,” the organisation said.
Kaksonen says the biological technology often
uses bacteria and archaea, which is another type
of prokaryotic microbe. Some treatment
processes use plant materials or even wetland
plants to provide a continuous carbon and
energy source for the microbes. These
biotechnologies mimic natural systems, but are
designed to provide optimum conditions to clean
up wastewater.
CSIRO Senior Research Scientist, Dr Ka Yu
Cheng, said: “Most of our work has two
dimensions. First, we aim to understand how the
biology works in the environment now. Second,
we try to engineer the process so that microbes
can work better to achieve what we want them to
do – such as finding the right mix of plants, the
right temperature or the right pH to increase the
activity of the microbial community.”
The CSIRO team uses DNA analysis to identify
the type of microbes that exist in mine water.
They then search through large databases to
identify more information about these tiny
helpers.
The team also do their own “bio prospecting”
– exploring various places in both natural
environments and in contaminated sites, to find
microbes that thrive in harsh environments,
according to CSIRO.
“We take samples from mine sites, existing
wastewater treatment processes or sediments,”
Dr Kaksonen said. Team members also look for
suitable organic solid or liquid waste streams,
such as the glycerol waste from biodiesel
production that could be used to drive
biotechnical mine water treatment.
“There could be some synergies for using
waste from one industrial sector as a feedstock
for another sector,” Dr Kaksonen said. “For
example, industrial symbiosis could happen
between biodiesel and mining industries, moving
both industries toward a more circular economy.”
The CSIRO team recently tested their
biotechnology processes in the laboratory on
mine water. They are now working with Evolution
to develop better treatment solutions for the
wastewater at Mt Rawdon. Dr Cheng said: “The
company is planning to use a wetland system to
treat mine wastewater. CSIRO’s team will
compare the effectiveness of sawdust, plant
material, ethanol and lactate to find the best
material that can support the microbial treatment
in a wetland-like system.”
Dr Kaksonen added: “The mine wastewater
from Evolution’s mine will contain sulphate and
metals, so we are working with the company to
combine hydrotalcite precipitation and biological
sulphate reduction.”
The Mt Rawdon gold deposit is a massive,
volcaniclastic hosted, low-grade gold deposit
that exhibits excellent characteristics conducive
to low cost mining and treatment, according to
Evolution Mining. The operation is one of its
most reliable mines, having produced more than
1.5 Moz of gold since first production in 2001.
Dr Kaksonen said: “While some mining
companies have used wetland systems and have
trialled various biotechnical processes, most
mine sites still use chemical treatments to clean
up mine water.”
A constructed wetland could potentially be a
cost-effective process to treat water to a stage
where it is safe to release back into the
environment. The wetland could be constructed
while the mine is operating and form a part of
the mine closure plan, CSIRO said.
Sludges and smaller volumes
The new Flowrox GeoBox™ innovation is a roll-
off unit for dewatering of waste, process sludges
and filtration of waters with high solids content.
It enables easy and cost-efficient separation and
transport of solids in the same closed unit.
Flowrox says that the GeoBox is an excellent
choice for applications where you do not want a
permanent or large-scale solution such as an
industrial filter.
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8. Flowrox GeoBox is a
specially designed geotextile
filtration and dewatering
container unit. Sludge or
water with flocculated solids
is pumped into the container.
The geotextile bag inside the
container effectively retains
the solids while allowing
water to pass through. The
GeoBox unit has waterproof
floor construction with a
drain valve, allowing clean
filtration and dewatering in a
closed space. For cold
conditions, the unit can be
equipped with thermal
insulation and heating.
“Even today, process and
waste sludges with a large
amount of water are often
transported by vacuum
trucks for final handling. The price per cubic
metre is high and in many cases, if the sludge
was drier, it could even be possible to use the
solids. Large-scale production filters can be too
costly in terms of benefits when it comes
primarily to waste treatment. Flowrox GeoBox is
designed as an inexpensive solution for
applications where sludge volumes are not huge
but cause unnecessarily high costs.”
For example, the solution is suitable for
levelling tanks, where the solids need to be
periodically removed from the bottom with an
excavator. Instead of emptying the entire tank,
the pump can continuously circulate the sludge
through the Flowrox GeoBox container placed
next to the pool. In this way, the solids
accumulate directly into the container instead of
the pool and are immediately ready for
transportation. Separation of solids can be
enhanced by flocculant and coagulant feed. The
container solution includes Flowrox's high-
quality hose pumps for both chemical supply and
the most demanding sludge pumping. “The
GeoBox container solution has brought great
savings, for example, in the treatment of process
water from the steel industry and peat-
containing sludge from the energy industry.”
DXB Pump & Power launches new
dewatering pumpset options for open
pits
DXB Pump & Power has expanded its range of
high pressure mine dewatering pumpsets for use
in low emission compliant markets with the
launch of the hh450/150 pumpset complete with
Caterpillar C15 ACERT 375 kW Stage IIIA 6-
cylinder engine and a high performance Cornell
Pump 6NHTB19 Redi-Prime pump. DXB Pump &
Power is the new UK OEM distributor for Cornell
Pump Company, based in the USA, and has been
packaging mine dewatering pumpsets for the
last two years for their customers in Europe,
primarily Stage IV powered pumpsets in sound
attenuated canopies that are fully bunded and
environmentally sound attenuated.
The company has now expanded their product
offering with the launch of less emission
compliant equipment for those markets where
Stage IV & V technology is unsuitable such as
markets in the Middle East and Africa that are
demanding no more than Stage IIIA engines and
less sophisticated engine management systems.
Powered by Cat C9 to C18 engines, the company
is offering six high pressure pumpsets all
capable of pressures in excess of 15 bar (150 m)
whilst capable of flows from as low as 300 m3/h
to over 900 m3/h with a single stage high
efficiency Redi-Prime pump from Cornell.
Simon Ruffles, DXB Managing Director and
Owner commented: “There are almost a dozen
mining industry focused procurement houses in
the UK buying everything from pencils to
pumpsets for the mines and traditionally they
have always bought from a single company for
the last 50 years but now with our entry there are
a couple of companies offering heavier duty
more efficient pumpsets that are able to
offer higher reliability and
lower running costs
to the mines-
regardless of
location.”
DXB Pump &
Power received an
enquiry last autumn
from a mining
procurement house
for a single pumpset
that expanded into a
£1 million pound
contract containing
12 sets, all Caterpillar
or Perkins powered,
and several hundred
metres of pipe, hoses
and accessories as
well. The company
had to procure the
Cat C15 engines and
fast-tracked their
delivery by working with the Cat dealer in the
local market. Cornell manufactured all 12 pump
ends in two months and DXB Pump & Power
airfreighted the pumps to the UK to ensure a
supply of the first 8 pumpsets before Christmas
shutdown and four large Cat C15 pumpsets before
the end of January 2019.
“We had the designs in place but with very low
levels of engine stocks here in the UK, we had to
source from elsewhere then airfreight the
equipment into our factory here which meant we
had the key components all in 10 weeks. We
worked closely with our UK supply chain and
fabricated all the heavy duty trailers in eight
weeks as well which meant assembly could start
immediately the equipment arrived from the USA.”
All the pumpsets were designed as double
axle trailer units using heavy duty off-road axles
and running gear and the mine specified every
optional extra including Wiggins fast fuelling
systems, LED work lamps/beacons and fire
safety equipment as part of the order. The four
largest pumpsets were ordered with the DXB
Pump STORM & STONE protection systems that
stop employees gaining access to the any
rotational parts on the pumpsets and also
protects the equipment from heavy weather and
rock blasts often seen in these mines.
WATER MANAGEMENT
56 International Mining | MARCH 2019
Flowrox GeoBox with LPP-T pump
DXB Pump & Power delivered a major order
recently for 12 pumpsets to a large mining
customer
IM
