414 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Diverter
A hydraulically actuated rock box diverting chute was cus-
tom designed for the application by KMP and the existing
chute following CV1201 was modified to accommodate
the change. The actuation time of the hydraulic mecha-
nism is approximately 2 seconds. After moving from the
“Product” position to the “Reject” position, several seconds
elapse while a layer of hung-up rock accumulates to form
an autogenous layer. The autogenous layer then reports to
the Product belt when actuation is reversed. (A video of the
diverter test can be accessed at https://www.youtube.com/
watch?v=vRLBnGgNmm4.)
Sensor/Diverter Control and Synchronization
A PLC integrated into the MRA electronics container sends
signals directly to the diverter gate controller. The direct
connection ensures that variable latency is not introduced
from external systems and ensures correct timing of pod
diversion. A bypass switch controlled by the KMP DCS
system allows the KMP control room to enable or disable
sorting functionality and preserve the flexibility of the 3
KMP processing lines.
The average speed of the conveyor belt is 3.41 m/s and
is highly consistent. The standard deviation of belt speed is
0.12 m/s. There are no other features which introduce vari-
ability into the time between sensor and diverter, such as
transfer chutes or surge bins.
Synchronization between the sensor and the diverter
was fine-tuned by plumbing a water spray over the con-
veyor after the MRA and integrating an electrical solenoid
valve via the MRA PLC. Two signals were programmed
into the PLC output, one to the solenoid valve and the sec-
ond to the diverter controller. A zero second delay was pro-
grammed into the solenoid valve signal and a longer delay
of approximately 15.7 seconds was initially programmed
into the diverter delay, then adjusted such that material
wetted by sprays during commissioning reports to the reject
conveyor and dry material reports to the product conveyor.
This accounts for the swing time and rock box autogenous
layer accumulation time to be tested experimentally to have
the most precise separation of material by pod. (A video
of the MRA/diverter synchronization spray tests can be
accessed at https://youtu.be/j3mSk2oUmLE)
Considerations for BOS Using Mineralogical
Grade Sensing
MRAs measure mineralogical content, typically of a single
mineral per analyser. Therefore, for measurement by MRA
to be suitable for use in BOS either:
a. the target mineral or minerals must represent sub-
stantially all of the copper bearing minerals in the
stream, or
b. the proportions of the target mineral to total copper
grade must be sufficiently well understood and reli-
able in occurrence.
In the KMP Sulphide circuit, chalcopyrite is the dominant
copper bearing mineral, hosting over 90% of the cop-
per in the mill feed. The feeds to the other two circuits at
Kansanshi, namely Mixed and Oxide, contain a wide range
of copper minerals with variable proportions of primary
and secondary copper sulphides as well as copper oxides
and silicates. Consequently, use of the MRA tuned for chal-
copyrite measurement is only suitable at Kansanshi for pri-
mary Sulphide ore.
Effective BOS outcomes rely implicitly on the effec-
tiveness of mining and geological functions to separate ore
types ahead of the crusher feed points for the respective
processing circuits. This reliance on upstream ore assign-
ment is not dissimilar to the three processing stream config-
uration of the processing plant, as each stream is optimised
for recovery of the mineralogy of the respective ore types.
VALIDATION TESTING
Validation testing is undertaken firstly to confirm the sen-
sor is measuring both accurately and precisely and secondly
to check that the full BOS system is operating effectively
and as designed.
Sensor accuracy (the difference between the measured
value and the true value) is tested by conducting measure-
ments of samples which are representative of feed and com-
paring these measurements to assays of the same samples.
Sensor precision (consistency or reproducibility of
measurements) is tested by performing repeated measure-
ments of the same samples and characterizing the standard
deviation of the measurement. This test is also used to
determine the lower detection limit of the sensor, which is
the 3-sigma, or 99 percentile, value above zero.
A separate type of test is necessary to evaluate overall
system functionality and ensure subsystem are operating
properly and synchronised with the other components of
the system. The separation of material by grade using BOS
is statistically impossible to achieve accidentally, but the
grades of the two streams can be relatively straightforward
to confirm. This can be done through sampling and assay-
ing of the streams by laboratory analysis, or using a method
pioneered by Kansanshi by campaign processing of a test
reject stockpile. This validation program for the Kansanshi
BOS system, as described below, is believed to be truly
Diverter
A hydraulically actuated rock box diverting chute was cus-
tom designed for the application by KMP and the existing
chute following CV1201 was modified to accommodate
the change. The actuation time of the hydraulic mecha-
nism is approximately 2 seconds. After moving from the
“Product” position to the “Reject” position, several seconds
elapse while a layer of hung-up rock accumulates to form
an autogenous layer. The autogenous layer then reports to
the Product belt when actuation is reversed. (A video of the
diverter test can be accessed at https://www.youtube.com/
watch?v=vRLBnGgNmm4.)
Sensor/Diverter Control and Synchronization
A PLC integrated into the MRA electronics container sends
signals directly to the diverter gate controller. The direct
connection ensures that variable latency is not introduced
from external systems and ensures correct timing of pod
diversion. A bypass switch controlled by the KMP DCS
system allows the KMP control room to enable or disable
sorting functionality and preserve the flexibility of the 3
KMP processing lines.
The average speed of the conveyor belt is 3.41 m/s and
is highly consistent. The standard deviation of belt speed is
0.12 m/s. There are no other features which introduce vari-
ability into the time between sensor and diverter, such as
transfer chutes or surge bins.
Synchronization between the sensor and the diverter
was fine-tuned by plumbing a water spray over the con-
veyor after the MRA and integrating an electrical solenoid
valve via the MRA PLC. Two signals were programmed
into the PLC output, one to the solenoid valve and the sec-
ond to the diverter controller. A zero second delay was pro-
grammed into the solenoid valve signal and a longer delay
of approximately 15.7 seconds was initially programmed
into the diverter delay, then adjusted such that material
wetted by sprays during commissioning reports to the reject
conveyor and dry material reports to the product conveyor.
This accounts for the swing time and rock box autogenous
layer accumulation time to be tested experimentally to have
the most precise separation of material by pod. (A video
of the MRA/diverter synchronization spray tests can be
accessed at https://youtu.be/j3mSk2oUmLE)
Considerations for BOS Using Mineralogical
Grade Sensing
MRAs measure mineralogical content, typically of a single
mineral per analyser. Therefore, for measurement by MRA
to be suitable for use in BOS either:
a. the target mineral or minerals must represent sub-
stantially all of the copper bearing minerals in the
stream, or
b. the proportions of the target mineral to total copper
grade must be sufficiently well understood and reli-
able in occurrence.
In the KMP Sulphide circuit, chalcopyrite is the dominant
copper bearing mineral, hosting over 90% of the cop-
per in the mill feed. The feeds to the other two circuits at
Kansanshi, namely Mixed and Oxide, contain a wide range
of copper minerals with variable proportions of primary
and secondary copper sulphides as well as copper oxides
and silicates. Consequently, use of the MRA tuned for chal-
copyrite measurement is only suitable at Kansanshi for pri-
mary Sulphide ore.
Effective BOS outcomes rely implicitly on the effec-
tiveness of mining and geological functions to separate ore
types ahead of the crusher feed points for the respective
processing circuits. This reliance on upstream ore assign-
ment is not dissimilar to the three processing stream config-
uration of the processing plant, as each stream is optimised
for recovery of the mineralogy of the respective ore types.
VALIDATION TESTING
Validation testing is undertaken firstly to confirm the sen-
sor is measuring both accurately and precisely and secondly
to check that the full BOS system is operating effectively
and as designed.
Sensor accuracy (the difference between the measured
value and the true value) is tested by conducting measure-
ments of samples which are representative of feed and com-
paring these measurements to assays of the same samples.
Sensor precision (consistency or reproducibility of
measurements) is tested by performing repeated measure-
ments of the same samples and characterizing the standard
deviation of the measurement. This test is also used to
determine the lower detection limit of the sensor, which is
the 3-sigma, or 99 percentile, value above zero.
A separate type of test is necessary to evaluate overall
system functionality and ensure subsystem are operating
properly and synchronised with the other components of
the system. The separation of material by grade using BOS
is statistically impossible to achieve accidentally, but the
grades of the two streams can be relatively straightforward
to confirm. This can be done through sampling and assay-
ing of the streams by laboratory analysis, or using a method
pioneered by Kansanshi by campaign processing of a test
reject stockpile. This validation program for the Kansanshi
BOS system, as described below, is believed to be truly