Miners tap waste for critical minerals

Cobalt Blue Holdings

28/06/2023 09:05

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      Rich potential in copper tailings in Australia
    

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      Rio Tinto produces tellurium from U.S. copper mine waste
    

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      Cobalt can be extracted from pyrite in mine waste 
    

  
    By Melanie Burton
       BRISBANE, June 28 (Reuters) - Extracting copper, nickel,
cobalt and other minerals from mine waste could provide a key
new source of the minerals needed for the energy transition
while at the same time cleaning up old mine sites, mining
executives said at a conference. 
    Australia by some estimates has more than 50,000 old mine
sites. Its government last month released a map of 1,050
tailings sites as potential sources of metals for which demand
is set to boom over coming decades for green energy products
including batteries and wind turbines. 
    BHP estimates the world will need an additional $100 billion
annually in capital investment in the resources sector to get on
track to meet the Paris aligned 1.5C scenario, or twice as much
copper, steel and potash and four times as much nickel in the
next 30 years as it used in the past 30.
    As resources with high metal content get harder to find and
develop, mine waste could be an important source for metals.
    "The sub 0.5% copper resources of tomorrow will be just as
attractive as the 2% copper resources of yesterday, delivering
the critical minerals the world needs to decarbonise at low
cost," said Laura Tyler, chief technical officer at top global
miner BHP.  
    "This means the mine waste of the past, will become some of
the new resources of the future," she told delegates to a
conference in Brisbane on Wednesday.
    There is around 5 million tonnes of copper in tailings waste
in Australia alone, estimates Gavin Mudd, an associate professor
at Australia's RMIT University, but it is unclear how much of
that could be recovered at the sites which often also host toxic
heavy metals.
    
    VALUABLE PRODUCTS 
        Rio Tinto has been working to find ways to take
traditional mining waste and turn it into useful products, head
of minerals Sinead Kaufman said at the conference.
    Some 85% of Rio's waste material, or around 400,000 tonnes,
from its aluminium operations in Canada is used to make new
products. 
    It has also begun producing tellurium, used in solar panels,
from waste generated by refining copper at its U.S. Kennecott
operation.  
    The critical mineral is difficult to mine at scale because
it is usually found in small, sparse rock deposits. Rio is now
ramping up its output to become the world's sixth biggest
producer.  
    "As a result we have become one of only two producers of the
critical minerals used in solar panels and other critical
equipment in the U.S.," Kaufman said.
    Government mapping of mine sites shows plenty of cobalt, as
well as copper, nickel and other metals, Associate Professor
Anita Parbhaker-Fox at the University of Queensland.
    Australia is the world's third-largest cobalt exporter as
well as the largest lithium producer and a significant producer
of copper.
    In Queensland, mapping shows plentiful cobalt at mine sites
in the state's north west, while on the west coast of Tasmania
state, cobalt can be found mixed in pyrite in mine waste, which
can oxidise over time into acid, Parbhaker-Fox said.
    Recovery of these metals will offer a chance to stop the
pyrite oxidising. 
    "We see mine waste as a huge opportunity," said Helen
Degeling, project acquisition manager at developer Cobalt Blue
 COB.AX .
    Cobalt Blue's processing plans target pyrite, which was
previously overlooked because it was difficult to process, but
with cobalt in demand for battery materials, now has value. 
    "Turning it into a useful product has not only economic
value but strong environmental positives as well," Degeling
said.
    

 (Reporting by Melanie Burton; Editing by Sonali Paul)
 ((melanie.burton@thomsonreuters.com Twitter: @MelanieMetals;
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