6
As the OCS-4D© has a data miner module, it enables
the visualization and association of the ore variabilities and
froth parameters. This data can be used to develop process
correlations, which can then be used to handle process dis-
turbances. The Expert Control System basically mimics the
best operator experience and knowledge. Therefore, the sys-
tem is enhanced so it can operate and optimize production
24/7.
The correlation of ore variability is learned and
observed, and the relative effect of a change in mill feed
grade upon froth velocity becomes obvious. Thus, modi-
fying froth velocity setpoint and reagents quickly are key
to disturbance handling (ore change). Then, the relative
change of Cu, Pb, and Zn mill feed grade are used to deter-
mine fast or slow response of froth velocity setpoint which
then effectively adjusts level setpoint and reagents setpoints.
The Doe Run flotation cells do not have individual air-
flow. Rather, the airflow control is by a single control valve
to each circuit (i.e., Zn rougher circuit has one airflow con-
trol). The control of airflow for each circuit is controlled by:
• the average froth velocity of circuit
– If average froth velocity is high, then the airflow
setpoint is decreased.
– If average froth velocity is low, then the airflow set-
point is increased.
• froth texture and concentrate grade (i.e., Cu assay in
final Pb concentrate). Operators often use this as a
barometer of concentrate quality or as an indicator
of the need for a reagent.
Thanks to the image miner module that allows storing
images along with data, it was possible to correlate images
with plant process variables and froth parameters.
Table 1 gives the idea of the numeric reading of froth
texture parameter. It suggests that with a high froth tex-
ture (0.80) that airflow should be increased since it needs
more bubbles to recover mineral, while with low froth tex-
ture (0.6), that airflow should be decreased because it may
float gangue mineral. The hypothesis is that froth texture
may have a correlation to Cu grade in final concentrate Pb,
and therefore froth texture and concentrate quality are used
for controlling airflow as well.
ZN CIRCUIT REAGENTS
Plant operators monitor froth (bubble size) flotation regu-
larly then adjust CuSO4 consumption. The rule of thumb
is when the bubble size is too big then increase CuSO4 and
when the bubble size is too small then decrease CuSO4.
This activity has been practiced manually over the years.
Bubble size and bubble count as one of the outputs from
VisioFroth ™ provide a quantitative number. Hence, com-
bining operator knowledge and bubble size information, a
best-practice control of CuSO4 reagent was developed.
It was obvious that the consumption of CuSO4 and
ore variabilities change the bubble size and bubble count
(Figure 7). The thermodynamics of the flotation process are
also affected by mill feed Zn head grade. Thus, these two
parameters were used for controlling CuSO4.
A relative change in mill feed Zn is used for control-
ling CuSO4. The bubble size and bubble count are used for
constraint control. CuSO4 logic is as detailed below:
Table 1. Froth texture of Cu Rougher
As the OCS-4D© has a data miner module, it enables
the visualization and association of the ore variabilities and
froth parameters. This data can be used to develop process
correlations, which can then be used to handle process dis-
turbances. The Expert Control System basically mimics the
best operator experience and knowledge. Therefore, the sys-
tem is enhanced so it can operate and optimize production
24/7.
The correlation of ore variability is learned and
observed, and the relative effect of a change in mill feed
grade upon froth velocity becomes obvious. Thus, modi-
fying froth velocity setpoint and reagents quickly are key
to disturbance handling (ore change). Then, the relative
change of Cu, Pb, and Zn mill feed grade are used to deter-
mine fast or slow response of froth velocity setpoint which
then effectively adjusts level setpoint and reagents setpoints.
The Doe Run flotation cells do not have individual air-
flow. Rather, the airflow control is by a single control valve
to each circuit (i.e., Zn rougher circuit has one airflow con-
trol). The control of airflow for each circuit is controlled by:
• the average froth velocity of circuit
– If average froth velocity is high, then the airflow
setpoint is decreased.
– If average froth velocity is low, then the airflow set-
point is increased.
• froth texture and concentrate grade (i.e., Cu assay in
final Pb concentrate). Operators often use this as a
barometer of concentrate quality or as an indicator
of the need for a reagent.
Thanks to the image miner module that allows storing
images along with data, it was possible to correlate images
with plant process variables and froth parameters.
Table 1 gives the idea of the numeric reading of froth
texture parameter. It suggests that with a high froth tex-
ture (0.80) that airflow should be increased since it needs
more bubbles to recover mineral, while with low froth tex-
ture (0.6), that airflow should be decreased because it may
float gangue mineral. The hypothesis is that froth texture
may have a correlation to Cu grade in final concentrate Pb,
and therefore froth texture and concentrate quality are used
for controlling airflow as well.
ZN CIRCUIT REAGENTS
Plant operators monitor froth (bubble size) flotation regu-
larly then adjust CuSO4 consumption. The rule of thumb
is when the bubble size is too big then increase CuSO4 and
when the bubble size is too small then decrease CuSO4.
This activity has been practiced manually over the years.
Bubble size and bubble count as one of the outputs from
VisioFroth ™ provide a quantitative number. Hence, com-
bining operator knowledge and bubble size information, a
best-practice control of CuSO4 reagent was developed.
It was obvious that the consumption of CuSO4 and
ore variabilities change the bubble size and bubble count
(Figure 7). The thermodynamics of the flotation process are
also affected by mill feed Zn head grade. Thus, these two
parameters were used for controlling CuSO4.
A relative change in mill feed Zn is used for control-
ling CuSO4. The bubble size and bubble count are used for
constraint control. CuSO4 logic is as detailed below:
Table 1. Froth texture of Cu Rougher