3456 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
PURPOSE OF THE PILOT TRIAL
The Main Objectives for the Mining
Company Included
Reduction of water consumption for both a very signifi-
cant Opex cost savings, as well as for the sustainable use of
resources.
• Minimizing the daily volume of tailings to the cur-
rent dam, which will increase its lifetime by more
than 5×. This will further improve the efficiency of
their tailings management system by returning water
to the process.
• Minimizing environmental impact of the tailings
operation and reducing the tailings footprint on local
rural land.
• Use of any polymer or coagulant is not permitted as
it negatively impacts the flotation process. Separation
must thus be done mechanically only.
• To pilot test the Z5E unit on site to ensure the pos-
sibility of scale-up to the Z92s as currently installed
at their original mine &plant site.
PILOT TRIAL
The pilot unit was brought up to optimal operating per-
formance relatively quickly once the initial feed issues were
overcome. These issues were: -
• settling of the larger sand particles in the longer-
than-usual feed line which choked the feed capacity
down and
• tramp larger mineral pieces (often more than 6mm,
some as large as 10mm) causing the lobe feed pump
to occasionally operate sub-optimally.
• Opportunity to test various scenaria using differ-
ing feed rates and centrifuge bowl &scroll speeds
was taken. This was done to ascertain whether vari-
ous optimum feed /differential speed combinations
between centrifuge bowl &scroll RPMs could suc-
cessfully be achieved. Clarity of the resultant centrate
(liquid discharge) and dryness of solids (DS) pro-
duced was measured against the input feed at each
setting.
The trial proved that the mining centrifuge can be rap-
idly recalibrated, allowing the running of multiple sepa-
rate “what-if” scenaria over the trial period. The 117 data
points selected represent both planned variables tests and
mimicked “steady state” operation. The planned total trial
length of full-time operation is for at least one calendar
month, ending early- to mid-July 2023.
METHODOLOGY
The Flottwe.g., model Z5E-4/451 decanter centrifuge
selected was equipped with a unique mining-state wear
package to ensure that wear on the bowl, scroll and all
entrance and exit points of the unit are protected against
the sliding wear that accompanies the typical mining mate-
rial found in mining process underflow. It is designed with
the durability to cope with occasional tramp materials typi-
cally found in a mining environment.
The pilot test equipment consisted of the decanter cen-
trifuge, it’s steel elevation stand, and it’s sealed /cooled con-
trol panel. It also included a feed pump and flowmeter. This
unit did not have a density meter, so readings were mostly
set at 15% solids for calculation purposes. The centrifuge
discharges both the solid &liquid streams by gravity. The
centrifuge’s control panel is connected to all instrumenta-
tion and monitors all aspects of operation. Immediate &
automatic adjustments are made to account for changes
in volume or density input feed – the master controls will
select any needed changes in RPM of bowl and/or scroll,
also their differential speed to maintain steady-state output.
Bearings are also continuously and automatically
monitored for any vibration changes, as is electrical feed.
Any loss of power will have the centrifuge automatically
cut input feed and drain the bowl of solids. Resumption
of power at any time will have the unit automatically come
back to steady production state, no matter which part of
the powering-off cycle is interrupted.
ANALYSIS
A field lab was set up at each site to analyze Dry Solids (DS)
for the feed, centrate and cake samples generated.
Duplicate samples were also taken for analysis at the
Flottwe.g., laboratories, which conducted additional analy-
sis including Total Suspended Solids (TSS) of feed and cen-
trate samples. Multiple samples of feed, solids and centrate
were sent to Flottweg’s USA as well as Germany laboratory
for analysis (Figure 10).
Figure 10. Typical example of one of the 117 field
samples taken of the feed, solids and centrate
PURPOSE OF THE PILOT TRIAL
The Main Objectives for the Mining
Company Included
Reduction of water consumption for both a very signifi-
cant Opex cost savings, as well as for the sustainable use of
resources.
• Minimizing the daily volume of tailings to the cur-
rent dam, which will increase its lifetime by more
than 5×. This will further improve the efficiency of
their tailings management system by returning water
to the process.
• Minimizing environmental impact of the tailings
operation and reducing the tailings footprint on local
rural land.
• Use of any polymer or coagulant is not permitted as
it negatively impacts the flotation process. Separation
must thus be done mechanically only.
• To pilot test the Z5E unit on site to ensure the pos-
sibility of scale-up to the Z92s as currently installed
at their original mine &plant site.
PILOT TRIAL
The pilot unit was brought up to optimal operating per-
formance relatively quickly once the initial feed issues were
overcome. These issues were: -
• settling of the larger sand particles in the longer-
than-usual feed line which choked the feed capacity
down and
• tramp larger mineral pieces (often more than 6mm,
some as large as 10mm) causing the lobe feed pump
to occasionally operate sub-optimally.
• Opportunity to test various scenaria using differ-
ing feed rates and centrifuge bowl &scroll speeds
was taken. This was done to ascertain whether vari-
ous optimum feed /differential speed combinations
between centrifuge bowl &scroll RPMs could suc-
cessfully be achieved. Clarity of the resultant centrate
(liquid discharge) and dryness of solids (DS) pro-
duced was measured against the input feed at each
setting.
The trial proved that the mining centrifuge can be rap-
idly recalibrated, allowing the running of multiple sepa-
rate “what-if” scenaria over the trial period. The 117 data
points selected represent both planned variables tests and
mimicked “steady state” operation. The planned total trial
length of full-time operation is for at least one calendar
month, ending early- to mid-July 2023.
METHODOLOGY
The Flottwe.g., model Z5E-4/451 decanter centrifuge
selected was equipped with a unique mining-state wear
package to ensure that wear on the bowl, scroll and all
entrance and exit points of the unit are protected against
the sliding wear that accompanies the typical mining mate-
rial found in mining process underflow. It is designed with
the durability to cope with occasional tramp materials typi-
cally found in a mining environment.
The pilot test equipment consisted of the decanter cen-
trifuge, it’s steel elevation stand, and it’s sealed /cooled con-
trol panel. It also included a feed pump and flowmeter. This
unit did not have a density meter, so readings were mostly
set at 15% solids for calculation purposes. The centrifuge
discharges both the solid &liquid streams by gravity. The
centrifuge’s control panel is connected to all instrumenta-
tion and monitors all aspects of operation. Immediate &
automatic adjustments are made to account for changes
in volume or density input feed – the master controls will
select any needed changes in RPM of bowl and/or scroll,
also their differential speed to maintain steady-state output.
Bearings are also continuously and automatically
monitored for any vibration changes, as is electrical feed.
Any loss of power will have the centrifuge automatically
cut input feed and drain the bowl of solids. Resumption
of power at any time will have the unit automatically come
back to steady production state, no matter which part of
the powering-off cycle is interrupted.
ANALYSIS
A field lab was set up at each site to analyze Dry Solids (DS)
for the feed, centrate and cake samples generated.
Duplicate samples were also taken for analysis at the
Flottwe.g., laboratories, which conducted additional analy-
sis including Total Suspended Solids (TSS) of feed and cen-
trate samples. Multiple samples of feed, solids and centrate
were sent to Flottweg’s USA as well as Germany laboratory
for analysis (Figure 10).
Figure 10. Typical example of one of the 117 field
samples taken of the feed, solids and centrate