XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 993
operational efficiency and safety goals. As the outlined con-
trol strategy took shape and received approval, signaling
the commencement of the APC system integration, a series
of anticipated challenges emerged, a common occurrence
in such implementations. These challenges were amplified
due to the integration being remote, a necessity imposed
by COVID-19 travel restrictions, which highlighted the
crucial role of continuous communication for the project
to be a success.
Amidst these challenges, the AwaRE ® APC system’s
ability to directly communicate with operators via the
Human Machine Interface (HMI) screens allowed the
operations team to easily understand the actions taken by
the system which mitigated the impact of the remote inte-
gration. Whenever the system executed an action, such as
adjusting oxygen levels, a message promptly appeared on
the operators’ HMI screens. This message, complete with a
reference to the control strategy and the conditions prompt-
ing the change, facilitated a comprehensive understanding
and trust within the operations team. The total transpar-
ency afforded by this direct communication mechanism
accelerated the establishment of trust between Pueblo Viejo
and AwaRE ®, proving to be a crucial factor in the success
of this remote integration.
METHODOLOGY
The control and optimization campaign at the Pueblo
Viejo operation started with a review of the existing control
strategy, evaluating opportunities for improvement, and
determining the value that could be gained from improved
automation.
Step 1—Control Review
An investigation was initiated by the Pueblo Viejo team
to assess the specific challenges faced regarding autoclave
control and to quantify the value addition of APC. The
goal of this study was to develop a roadmap to operational
excellence. The study found that the Autoclave circuit was
a major bottleneck for the overall processing plant and that
significant improvement could be realized in stabilizing the
autoclave process parameters, which would consequently
allow for increased plant throughput.
The following autoclave process parameters were
considered:
• Vent temperature
• Vent valve position
• Pressure
• Slurry level
• Oxidation efficiency
The following controllers were available to manage the
abovementioned parameters:
• Feed flow (two high pressure feed pumps)
• Oxygen injection (four injection points)
• HPCW (High Pressure Cooling Water) injection
(one point per autoclave chamber)
During the investigation, it was found that the autoclaves
are often run in a cyclical manner: hot and cold cycles were
present, with the throughput oscillating accordingly as
shown in Figure 2 and Figure 3. In essence, the study indi-
cated that significant opportunities existed to first stabilize
and then improve the performance of the autoclave circuit.
Pueblo Viejo then engaged in a collaborative effort with
Woodgrove Technologies to jointly investigate the existing
control strategy. Together, valuable control improvement
opportunities were identified such as implementing ratio
control for the managed variables (oxygen injection per
compartment and HPCW injection per compartment),
which had the potential to stabilize the autoclave process
Figure 2. AC150 Feed flow and oxidation efficiency from June 22, 2020, to July 03, 2020
operational efficiency and safety goals. As the outlined con-
trol strategy took shape and received approval, signaling
the commencement of the APC system integration, a series
of anticipated challenges emerged, a common occurrence
in such implementations. These challenges were amplified
due to the integration being remote, a necessity imposed
by COVID-19 travel restrictions, which highlighted the
crucial role of continuous communication for the project
to be a success.
Amidst these challenges, the AwaRE ® APC system’s
ability to directly communicate with operators via the
Human Machine Interface (HMI) screens allowed the
operations team to easily understand the actions taken by
the system which mitigated the impact of the remote inte-
gration. Whenever the system executed an action, such as
adjusting oxygen levels, a message promptly appeared on
the operators’ HMI screens. This message, complete with a
reference to the control strategy and the conditions prompt-
ing the change, facilitated a comprehensive understanding
and trust within the operations team. The total transpar-
ency afforded by this direct communication mechanism
accelerated the establishment of trust between Pueblo Viejo
and AwaRE ®, proving to be a crucial factor in the success
of this remote integration.
METHODOLOGY
The control and optimization campaign at the Pueblo
Viejo operation started with a review of the existing control
strategy, evaluating opportunities for improvement, and
determining the value that could be gained from improved
automation.
Step 1—Control Review
An investigation was initiated by the Pueblo Viejo team
to assess the specific challenges faced regarding autoclave
control and to quantify the value addition of APC. The
goal of this study was to develop a roadmap to operational
excellence. The study found that the Autoclave circuit was
a major bottleneck for the overall processing plant and that
significant improvement could be realized in stabilizing the
autoclave process parameters, which would consequently
allow for increased plant throughput.
The following autoclave process parameters were
considered:
• Vent temperature
• Vent valve position
• Pressure
• Slurry level
• Oxidation efficiency
The following controllers were available to manage the
abovementioned parameters:
• Feed flow (two high pressure feed pumps)
• Oxygen injection (four injection points)
• HPCW (High Pressure Cooling Water) injection
(one point per autoclave chamber)
During the investigation, it was found that the autoclaves
are often run in a cyclical manner: hot and cold cycles were
present, with the throughput oscillating accordingly as
shown in Figure 2 and Figure 3. In essence, the study indi-
cated that significant opportunities existed to first stabilize
and then improve the performance of the autoclave circuit.
Pueblo Viejo then engaged in a collaborative effort with
Woodgrove Technologies to jointly investigate the existing
control strategy. Together, valuable control improvement
opportunities were identified such as implementing ratio
control for the managed variables (oxygen injection per
compartment and HPCW injection per compartment),
which had the potential to stabilize the autoclave process
Figure 2. AC150 Feed flow and oxidation efficiency from June 22, 2020, to July 03, 2020