6
bubble mineral loading, which in turn is used to tell if the
bubbles are being used efficiently for the flotation.
The optimization module is an extension of what
would be typically included with the VisioFroth ™ system.
This module adjusts froth velocity setpoints to reach target
concentrate grades, ultimately improving recovery auto-
matically and continually. One of the major challenges fac-
ing this system at Buick Mill is that Buick Mill’s ore comes
from several very distinct underground areas. Thus, several
very different ore grades may be present in the mill feed in
quick succession, leading to significant swings in availabil-
ity and presence for each of the minerals during even just
a couple of hours. For example, it is not unusual to see the
Zn grade in the feed double over the course of 20 minutes
before dropping back down to its previous level within an
hour or so.
A major challenge is when the target concentrate grade
is reached for lead, zinc or copper and “the machine” has
done its function as instructed, it does not respond to sud-
den spikes in ore grade, or slowly when ore grade drops
sharply, since the goal of reaching target concentrate grade
is already met. Deep machine learning is therefore needed
and developed. The major breakthrough allowing the
optimization module to function even with these consid-
erable swings is largely possible due to the capabilities of
the VisioFroth ™ system’s software, OCS-4D©. The expert
control system registers significant spikes or drops in the
feed grade, and if within a certain reasonable time frame
a similar spike or drop is seen in froth depth associated
with that same element, the velocity setpoint adjustments
are accordingly sped up or sharply decreased temporar-
ily to handle the change restoring to froth depth prior to
spike or drop in ore grade. This increased responsivity in
response to specific predicted conditions has been integral
to keeping the optimization module online despite these
ore variations.
It is important to note that the delay between the spike
or drop being detected and the associated increase in froth
depths is not a hard, fixed value. Rather, a spike or sharp
drop in feed grade primes the system to detect such a froth
depth increase or decrease. Until that change in froth depth,
increasing or decreasing, is actually observed by machine,
however, the system does not make froth velocity setpoint
changes based on it. Not every feed grade change observed
by the online X-ray corresponds to a significant quantity
of material, as the X-ray only assays the mill feed for about
a minute out of every six minutes. Thus, the assay value is
not used to forecast an increase in the cell loading, but to
indicate the possibility that it may be observed on another
sensor (the froth depth, in this case).
There are several future steps enabled by this system.
Most importantly, as a purely digital control system, it can
transcend the boundaries between traditionally separated
unit operations. There is nothing inherent to the system
that prevents its application to controlling grinding or fil-
tration. Even more so, there is nothing preventing the sys-
tem from using sensor data from as an example flotation to
make adjustments in the rod mill and ball mill parameters.
One application could be that if in flotation all the soft
sensors used to detect marcasite are indicating the presence
of marcasite, then it would be possible to automatically
reduce feed rate to ensure that the minerals in the marcasite
ores are liberated.
Buick Mill constant learns about and expands features,
functions, and applications of the Digital One expert con-
trol and operating system beyond flotation from which it
was started and developed. Digital One now consists of
“Digital Operator” mimicking operator’s best practices
Expert of Things “EoT,” Expert Flotation and Expert
Grinding. Most importantly, the integrated expert flota-
tion and expert grinding in Digital One leads to flotation
control based on applied thermodynamics and kinetics,
much needed to process complex ores most efficiently at
Buick Mill and the other Doe Run mills and to expand
various ore especially copper ore resources. It is currently
being tested and applied in different scenarios and being
vigorously examined. These developments and the funda-
mentals supporting the applications are certainly beyond
the scope of this article and are subjects of other articles
and presentations.
CONCLUSIONS
The expert control system and hybrid reagent system intro-
duced at Buick Mill fundamentally transforms its capabili-
ties. Since the implementation of the control and reagent
scheme to handle marcasite ores in 2022, over 200,000 tons
of marcasite high lead high copper ores have been processed,
making salable concentrates. This is a direct result of these
improvements to the reagent scheme and expert control,
creating significant value from the mill at minimal expense.
However, the marcasite ores are only one of the high-
lights of Buick Mill’s transformation. The expert control
system has managed to be maintained on the production
line, achieving operator acceptance while also reaching out
to control all aspects of the flotation plant. It is possible and
we demonstrate that we can completely take over a flotation
plant with safe and robust automation, barring local events
requiring operator intervention. Expert flotation control
has been running zinc and copper circuits since December
bubble mineral loading, which in turn is used to tell if the
bubbles are being used efficiently for the flotation.
The optimization module is an extension of what
would be typically included with the VisioFroth ™ system.
This module adjusts froth velocity setpoints to reach target
concentrate grades, ultimately improving recovery auto-
matically and continually. One of the major challenges fac-
ing this system at Buick Mill is that Buick Mill’s ore comes
from several very distinct underground areas. Thus, several
very different ore grades may be present in the mill feed in
quick succession, leading to significant swings in availabil-
ity and presence for each of the minerals during even just
a couple of hours. For example, it is not unusual to see the
Zn grade in the feed double over the course of 20 minutes
before dropping back down to its previous level within an
hour or so.
A major challenge is when the target concentrate grade
is reached for lead, zinc or copper and “the machine” has
done its function as instructed, it does not respond to sud-
den spikes in ore grade, or slowly when ore grade drops
sharply, since the goal of reaching target concentrate grade
is already met. Deep machine learning is therefore needed
and developed. The major breakthrough allowing the
optimization module to function even with these consid-
erable swings is largely possible due to the capabilities of
the VisioFroth ™ system’s software, OCS-4D©. The expert
control system registers significant spikes or drops in the
feed grade, and if within a certain reasonable time frame
a similar spike or drop is seen in froth depth associated
with that same element, the velocity setpoint adjustments
are accordingly sped up or sharply decreased temporar-
ily to handle the change restoring to froth depth prior to
spike or drop in ore grade. This increased responsivity in
response to specific predicted conditions has been integral
to keeping the optimization module online despite these
ore variations.
It is important to note that the delay between the spike
or drop being detected and the associated increase in froth
depths is not a hard, fixed value. Rather, a spike or sharp
drop in feed grade primes the system to detect such a froth
depth increase or decrease. Until that change in froth depth,
increasing or decreasing, is actually observed by machine,
however, the system does not make froth velocity setpoint
changes based on it. Not every feed grade change observed
by the online X-ray corresponds to a significant quantity
of material, as the X-ray only assays the mill feed for about
a minute out of every six minutes. Thus, the assay value is
not used to forecast an increase in the cell loading, but to
indicate the possibility that it may be observed on another
sensor (the froth depth, in this case).
There are several future steps enabled by this system.
Most importantly, as a purely digital control system, it can
transcend the boundaries between traditionally separated
unit operations. There is nothing inherent to the system
that prevents its application to controlling grinding or fil-
tration. Even more so, there is nothing preventing the sys-
tem from using sensor data from as an example flotation to
make adjustments in the rod mill and ball mill parameters.
One application could be that if in flotation all the soft
sensors used to detect marcasite are indicating the presence
of marcasite, then it would be possible to automatically
reduce feed rate to ensure that the minerals in the marcasite
ores are liberated.
Buick Mill constant learns about and expands features,
functions, and applications of the Digital One expert con-
trol and operating system beyond flotation from which it
was started and developed. Digital One now consists of
“Digital Operator” mimicking operator’s best practices
Expert of Things “EoT,” Expert Flotation and Expert
Grinding. Most importantly, the integrated expert flota-
tion and expert grinding in Digital One leads to flotation
control based on applied thermodynamics and kinetics,
much needed to process complex ores most efficiently at
Buick Mill and the other Doe Run mills and to expand
various ore especially copper ore resources. It is currently
being tested and applied in different scenarios and being
vigorously examined. These developments and the funda-
mentals supporting the applications are certainly beyond
the scope of this article and are subjects of other articles
and presentations.
CONCLUSIONS
The expert control system and hybrid reagent system intro-
duced at Buick Mill fundamentally transforms its capabili-
ties. Since the implementation of the control and reagent
scheme to handle marcasite ores in 2022, over 200,000 tons
of marcasite high lead high copper ores have been processed,
making salable concentrates. This is a direct result of these
improvements to the reagent scheme and expert control,
creating significant value from the mill at minimal expense.
However, the marcasite ores are only one of the high-
lights of Buick Mill’s transformation. The expert control
system has managed to be maintained on the production
line, achieving operator acceptance while also reaching out
to control all aspects of the flotation plant. It is possible and
we demonstrate that we can completely take over a flotation
plant with safe and robust automation, barring local events
requiring operator intervention. Expert flotation control
has been running zinc and copper circuits since December