4
undersize reports back to the primary cyclone feed hopper.
The hydroclone overflow (fine) flows by gravity through a
pipe to the flotation process where the targeted feed size is
a P80 of 180 µm.
The rougher flotation circuit comprises seven con-
ventional tank cells (300 m3 each). Rougher concentrate
is pumped to the regrind stage which has a vertical mill,
14.9' × 45' with a 932 kW motor, in closed circuit with a
hydrocyclone cluster. The overflow from the regrind hydro-
cyclone cluster, target P80 of 38 µm, discharges by gravity
to the feed box of the first cleaning stage.
The first stage of cleaning consists of two conventional
tank cells (130 m3 each). Tailings from the first cleaner
stage feeds directly to the scavenger circuit, consisting of
three conventional cells (130 m3 each). Concentrate from
the scavengers joins the rougher concentrate in the regrind
circuit. The rougher and scavenger tailings are sent to the
tailings thickener. Concentrate produced in the first clean-
ing stage is discharged to a transfer hopper and pumped to
the second cleaning stage (two 4.75 m diameter flotation
column cells).
Concentrate from the second cleaners flows by gravity
to a transfer hopper and is pumped to the third and final
cleaning stage (one 4.75 m diameter column flotation cell).
The tailings from the third cleaning stage discharges by
gravity to the second cleaning stage feed hopper. The tail-
ings from the second cleaning stage discharges to a transfer
box and is pumped back to the first cleaning stage.
The copper concentrate from the final cleaner flows by
gravity to a 20 m diameter high rate concentrate thickener.
From the thickener, two peristaltic pumps, one operating
and one stand-by, transfer the thickened concentrate to
an agitated tank. This tank has one centrifugal pump with
variable speed and feeds the 108 m2 filter press. Dewatered
filter cake (target 9% moisture) discharges to grade and is
loaded by a front-end loader into trucks which transports
the concentrate from the plant to a port for shipment.
The filtrate from the filter discharges into a transfer box,
from where it is pumped back to the concentrate thickener.
Process water recovered from the concentrate thickener
overflow is sent to a dedicated process water tank and dis-
tributed back to the plant by three pumps, two operating in
parallel and one stand- by.
The combined final tailings, formed by the rougher
tailings and the scavenger tailings, flows by gravity to a
transfer box which feeds a 55 m diameter high-rate tailings
thickener. Water recovered from the tailing thickener is sent
to the process water tank. Thickened tailings (underflow)
are pumped 3.3 km to a Sand Plant consisting of a hydro-
cyclone cluster and a slimes thickener. The hydrocyclone
classifies the tailings to produce a coarse sand (underflow)
which is pumped to the tailings storage facility (TSF) and
used to build the dam wall. The hydrocyclone fines (over-
flow) is sent to the 55 m diameter high-rate slimes thickener
for water recovery. The thickened underflow is pumped and
deposited in the TSF and the thickener overflow water is
returned to the main process water tank for distribution to
the sulphide concentrator.
The Mantoverde TSF dam is a conventional dam con-
structed using the center-line method with a 2:1 upstream
slope and 4:1 downstream slope. The upstream wall is pro-
tected by an impermeable liner to prevent seepage through
the wall. The dam design has provision for drainage (col-
lectors, foot and blanket drains) and drainage collection
ponds.
Figure 3 shows an aerial view of the extensive
Mantoverde production and ancillary facilities.
COBALT PROJECT
There are three key process operations required for cobalt
recovery at Mantoverde:
• Pyrite scavenging from the cleaner tails using pneu-
matic froth flotation machines to produce a cobalt-
rich pyrite concentrate. The thickened pyrite con-
centrate is combined with SX raffinate and inoculum
and added to the agglomeration drums together with
the oxide ore.
• Conversion of the existing acid heap leach facility
to an oxidative acid heap leach facility via the intro-
duction of heap aeration and bacterial augmentation
systems.
• Recovery of cobalt via a solution treatment and
CCIX (continuous countercurrent ion exchange)
facility treating a bleed stream of copper SX raffinate
Each is described in more detail below.
Pyrite Scavenging
The original sulfide flotation circuit was developed to oper-
ate using a thionocarbamate primary collector (Syensqo’s
Aero 9950) and a xanthate secondary collector (sodium
isobutyl xanthate, SIBX). This reagent scheme is optimal
for producing a clean copper concentrate with high gold
recovery but may not be optimal for delivering an effec-
tive copper/pyrite separation in the cleaning circuit—
a necessity if a pyrite scavenging stage is to be added to
treat the cleaner tails. Fortunately, Capstone has recently
successfully completed test work under similar conditions
for the nearby Santo Domingo project, identifying a more
selective xanthate and lime reagent scheme that allowed for
undersize reports back to the primary cyclone feed hopper.
The hydroclone overflow (fine) flows by gravity through a
pipe to the flotation process where the targeted feed size is
a P80 of 180 µm.
The rougher flotation circuit comprises seven con-
ventional tank cells (300 m3 each). Rougher concentrate
is pumped to the regrind stage which has a vertical mill,
14.9' × 45' with a 932 kW motor, in closed circuit with a
hydrocyclone cluster. The overflow from the regrind hydro-
cyclone cluster, target P80 of 38 µm, discharges by gravity
to the feed box of the first cleaning stage.
The first stage of cleaning consists of two conventional
tank cells (130 m3 each). Tailings from the first cleaner
stage feeds directly to the scavenger circuit, consisting of
three conventional cells (130 m3 each). Concentrate from
the scavengers joins the rougher concentrate in the regrind
circuit. The rougher and scavenger tailings are sent to the
tailings thickener. Concentrate produced in the first clean-
ing stage is discharged to a transfer hopper and pumped to
the second cleaning stage (two 4.75 m diameter flotation
column cells).
Concentrate from the second cleaners flows by gravity
to a transfer hopper and is pumped to the third and final
cleaning stage (one 4.75 m diameter column flotation cell).
The tailings from the third cleaning stage discharges by
gravity to the second cleaning stage feed hopper. The tail-
ings from the second cleaning stage discharges to a transfer
box and is pumped back to the first cleaning stage.
The copper concentrate from the final cleaner flows by
gravity to a 20 m diameter high rate concentrate thickener.
From the thickener, two peristaltic pumps, one operating
and one stand-by, transfer the thickened concentrate to
an agitated tank. This tank has one centrifugal pump with
variable speed and feeds the 108 m2 filter press. Dewatered
filter cake (target 9% moisture) discharges to grade and is
loaded by a front-end loader into trucks which transports
the concentrate from the plant to a port for shipment.
The filtrate from the filter discharges into a transfer box,
from where it is pumped back to the concentrate thickener.
Process water recovered from the concentrate thickener
overflow is sent to a dedicated process water tank and dis-
tributed back to the plant by three pumps, two operating in
parallel and one stand- by.
The combined final tailings, formed by the rougher
tailings and the scavenger tailings, flows by gravity to a
transfer box which feeds a 55 m diameter high-rate tailings
thickener. Water recovered from the tailing thickener is sent
to the process water tank. Thickened tailings (underflow)
are pumped 3.3 km to a Sand Plant consisting of a hydro-
cyclone cluster and a slimes thickener. The hydrocyclone
classifies the tailings to produce a coarse sand (underflow)
which is pumped to the tailings storage facility (TSF) and
used to build the dam wall. The hydrocyclone fines (over-
flow) is sent to the 55 m diameter high-rate slimes thickener
for water recovery. The thickened underflow is pumped and
deposited in the TSF and the thickener overflow water is
returned to the main process water tank for distribution to
the sulphide concentrator.
The Mantoverde TSF dam is a conventional dam con-
structed using the center-line method with a 2:1 upstream
slope and 4:1 downstream slope. The upstream wall is pro-
tected by an impermeable liner to prevent seepage through
the wall. The dam design has provision for drainage (col-
lectors, foot and blanket drains) and drainage collection
ponds.
Figure 3 shows an aerial view of the extensive
Mantoverde production and ancillary facilities.
COBALT PROJECT
There are three key process operations required for cobalt
recovery at Mantoverde:
• Pyrite scavenging from the cleaner tails using pneu-
matic froth flotation machines to produce a cobalt-
rich pyrite concentrate. The thickened pyrite con-
centrate is combined with SX raffinate and inoculum
and added to the agglomeration drums together with
the oxide ore.
• Conversion of the existing acid heap leach facility
to an oxidative acid heap leach facility via the intro-
duction of heap aeration and bacterial augmentation
systems.
• Recovery of cobalt via a solution treatment and
CCIX (continuous countercurrent ion exchange)
facility treating a bleed stream of copper SX raffinate
Each is described in more detail below.
Pyrite Scavenging
The original sulfide flotation circuit was developed to oper-
ate using a thionocarbamate primary collector (Syensqo’s
Aero 9950) and a xanthate secondary collector (sodium
isobutyl xanthate, SIBX). This reagent scheme is optimal
for producing a clean copper concentrate with high gold
recovery but may not be optimal for delivering an effec-
tive copper/pyrite separation in the cleaning circuit—
a necessity if a pyrite scavenging stage is to be added to
treat the cleaner tails. Fortunately, Capstone has recently
successfully completed test work under similar conditions
for the nearby Santo Domingo project, identifying a more
selective xanthate and lime reagent scheme that allowed for