1
25-019
Cobalt Recovery from Mill Tailings at Mantoverde Copper Mine
Peter Amelunxen
Capstone Copper Corp, On, Canada
Brandon Akerstrom
Capstone Copper Corp, AZ, USA
Kain Nugent
Global Resource Engineering, Co, USA
Todd Harvey
Global Resource Engineering, Co, USA
Willem Duyvesteyn
EMC LLC, NV, USA
ABSTRACT
In 2024, Capstone Copper Corp commissioned a new sul-
fide flotation plant at Mantoverde in the Atacama region of
Chile to process copper ore at a design rate of 32,000tpd.
The pyrite associated with the copper ore body contains
cobalt in solid solution, with Co replacing Fe in the pyrite
matrix. As per the existing sulfide flotation flowsheet most
of the pyrite is depressed and sent to tailings via the cleaner
scavenger tail stream. A new project considers the recovery
of the pyrite from the cleaner-scavenger tails via froth flota-
tion to produce a cobaltiferous pyrite concentrate, which
is then leached via the existing dynamic copper leach pad
to oxidize the pyrite and dissolve the cobalt. The cobalt is
recovered from the solution by treating a bleed stream of
copper SX raffinate through a continuous, counter-current
ion exchange (CCIX) facility. This approach to by-produc-
tion of cobalt confers numerous benefits, including reduced
costs compared with alternative cobalt recovery processes,
reduced acid consumption in the heap leach, increased cop-
per production, and reduced acid mine drainage potential
due to the removal of pyrite from the mill tailings.
INTRODUCTION
Geology
The Mantoverde Mine is a copper mine with active open-
pit mining and processing facilities including a copper
concentrator to process sulfide ore and heap and dump
(Run-of-Mine, ROM) leaching with solvent extraction
and electrowinning SX-EW to treat oxide ore for cathode
production. Mantoverde is located in the province of
Chañaral, Atacama Region, Republic of Chile.
The deposit is an iron oxide–copper–gold (IOCG)
deposit from the Chilean Iron Belt located within the
Atacama Fault System. Locally, it is situated along the
Mantoverde Fault, which is a 12 km long subsidiary
structure between two north-south main branches of the
Atacama Fault System.
The copper mineralization is hosted in at least three
geological environments: i) tabular bodies along the FMV
with discontinuous copper mineralization and domi-
nated by magnetite and specularite (Mantoverde Sur and
Mantoverde Norte respectively) ii) Pipe breccias (Celso
and Mantoruso) in the northwest of the area and iii) irreg-
ular west dipping tectonic breccias (Montecristo).
The deposit is oxidized to approximately 200 m depth.
Breccias in the sloping fault block contain abundant hema-
tite with brochantite, antlerite, chrysocolla, malachite and
minor atacamite, which occur in veinlets, patches and dis-
seminated in the specularite matrix.
Hypogene mineralization below the oxide zone is char-
acterized by disseminated chalcopyrite and pyrite (chal-
copyrite/pyrite =5/1) within the specularite and lesser
magnetite cemented hydrothermal breccias and associated
stockworks.
Between the oxidized zone and the hypogene sulphide
zone there is a thin sub-horizontal mixed zone. The mixed
zone has a thickness ranging from 15 m to 45 m depend-
ing on its proximity to the Mantoverde fault. Mixed zone
mineralization is characterized by chalcocite (±covellite),
25-019
Cobalt Recovery from Mill Tailings at Mantoverde Copper Mine
Peter Amelunxen
Capstone Copper Corp, On, Canada
Brandon Akerstrom
Capstone Copper Corp, AZ, USA
Kain Nugent
Global Resource Engineering, Co, USA
Todd Harvey
Global Resource Engineering, Co, USA
Willem Duyvesteyn
EMC LLC, NV, USA
ABSTRACT
In 2024, Capstone Copper Corp commissioned a new sul-
fide flotation plant at Mantoverde in the Atacama region of
Chile to process copper ore at a design rate of 32,000tpd.
The pyrite associated with the copper ore body contains
cobalt in solid solution, with Co replacing Fe in the pyrite
matrix. As per the existing sulfide flotation flowsheet most
of the pyrite is depressed and sent to tailings via the cleaner
scavenger tail stream. A new project considers the recovery
of the pyrite from the cleaner-scavenger tails via froth flota-
tion to produce a cobaltiferous pyrite concentrate, which
is then leached via the existing dynamic copper leach pad
to oxidize the pyrite and dissolve the cobalt. The cobalt is
recovered from the solution by treating a bleed stream of
copper SX raffinate through a continuous, counter-current
ion exchange (CCIX) facility. This approach to by-produc-
tion of cobalt confers numerous benefits, including reduced
costs compared with alternative cobalt recovery processes,
reduced acid consumption in the heap leach, increased cop-
per production, and reduced acid mine drainage potential
due to the removal of pyrite from the mill tailings.
INTRODUCTION
Geology
The Mantoverde Mine is a copper mine with active open-
pit mining and processing facilities including a copper
concentrator to process sulfide ore and heap and dump
(Run-of-Mine, ROM) leaching with solvent extraction
and electrowinning SX-EW to treat oxide ore for cathode
production. Mantoverde is located in the province of
Chañaral, Atacama Region, Republic of Chile.
The deposit is an iron oxide–copper–gold (IOCG)
deposit from the Chilean Iron Belt located within the
Atacama Fault System. Locally, it is situated along the
Mantoverde Fault, which is a 12 km long subsidiary
structure between two north-south main branches of the
Atacama Fault System.
The copper mineralization is hosted in at least three
geological environments: i) tabular bodies along the FMV
with discontinuous copper mineralization and domi-
nated by magnetite and specularite (Mantoverde Sur and
Mantoverde Norte respectively) ii) Pipe breccias (Celso
and Mantoruso) in the northwest of the area and iii) irreg-
ular west dipping tectonic breccias (Montecristo).
The deposit is oxidized to approximately 200 m depth.
Breccias in the sloping fault block contain abundant hema-
tite with brochantite, antlerite, chrysocolla, malachite and
minor atacamite, which occur in veinlets, patches and dis-
seminated in the specularite matrix.
Hypogene mineralization below the oxide zone is char-
acterized by disseminated chalcopyrite and pyrite (chal-
copyrite/pyrite =5/1) within the specularite and lesser
magnetite cemented hydrothermal breccias and associated
stockworks.
Between the oxidized zone and the hypogene sulphide
zone there is a thin sub-horizontal mixed zone. The mixed
zone has a thickness ranging from 15 m to 45 m depend-
ing on its proximity to the Mantoverde fault. Mixed zone
mineralization is characterized by chalcocite (±covellite),