546 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
energy-efficient equipment and the optimization of the
process flowsheet, including incorporation of dry milling
utilized prior to the dry magnetic separation stage. Dry
tailings disposal also has other environmental benefits and
potentially reduces future tailings storage failure risks.
The proposed processing plant will treat about 15
million tons per annum (Mt/a) of ore and have a nomi-
nal production capacity of 5 Mt/a of magnetite concen-
trate. The plant is designed to be modular, so that it can
be expanded in the future to meet increased demand, with
pipeline capacity design at 10 Mt/a of concentrate. Overall,
the change from wet milling and wet separation to dry mill-
ing and dry separation for the primary grinding circuit led
to an estimated 24% plant water consumption reduction, a
substantial step into a more sustainable mineral processing
plant design. The main sustainability advantages are sum-
marized in Table 3.
CONCLUSIONS AND
RECOMMENDATIONS
The test work and comparisons provide the following
conclusions:
Open circuit VRM milling to achieve P80 85 to 100 µm
proved to be highly energy efficient for Southdown ore.
Indicative crude grit testing (grit generated by open
circuit pilot VRM) showed a high degree of liberation of
barren gangue within the grit stream and that magnetic
separation of the grit produced barren waste with minimal
magnetite losses.
Figure 8. Closeup of VRMs and bag houses
Table 3. industrial design comparison (adjusted to P
80 85 µm common basis)
VRM WET Milling Relative VRM Benefit
Overall specific power consumption 12.3 kWh/t 20.8 kWh/t 41%
Non-mag Rejected 35% 32% 9%
Mass of IMS Concentrate for Regrinding 39.7% of feed 40% of feed 5.5%
Plant water consumption 3.9 Gl/a 5.1 Gl/a 24%
Tailings disposal Dry stacking Wet pond
energy-efficient equipment and the optimization of the
process flowsheet, including incorporation of dry milling
utilized prior to the dry magnetic separation stage. Dry
tailings disposal also has other environmental benefits and
potentially reduces future tailings storage failure risks.
The proposed processing plant will treat about 15
million tons per annum (Mt/a) of ore and have a nomi-
nal production capacity of 5 Mt/a of magnetite concen-
trate. The plant is designed to be modular, so that it can
be expanded in the future to meet increased demand, with
pipeline capacity design at 10 Mt/a of concentrate. Overall,
the change from wet milling and wet separation to dry mill-
ing and dry separation for the primary grinding circuit led
to an estimated 24% plant water consumption reduction, a
substantial step into a more sustainable mineral processing
plant design. The main sustainability advantages are sum-
marized in Table 3.
CONCLUSIONS AND
RECOMMENDATIONS
The test work and comparisons provide the following
conclusions:
Open circuit VRM milling to achieve P80 85 to 100 µm
proved to be highly energy efficient for Southdown ore.
Indicative crude grit testing (grit generated by open
circuit pilot VRM) showed a high degree of liberation of
barren gangue within the grit stream and that magnetic
separation of the grit produced barren waste with minimal
magnetite losses.
Figure 8. Closeup of VRMs and bag houses
Table 3. industrial design comparison (adjusted to P
80 85 µm common basis)
VRM WET Milling Relative VRM Benefit
Overall specific power consumption 12.3 kWh/t 20.8 kWh/t 41%
Non-mag Rejected 35% 32% 9%
Mass of IMS Concentrate for Regrinding 39.7% of feed 40% of feed 5.5%
Plant water consumption 3.9 Gl/a 5.1 Gl/a 24%
Tailings disposal Dry stacking Wet pond