994 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
parameters significantly. This partnership aimed to lever-
age both parties’ collective expertise for mutual success and
operational excellence.
Step 2—Autoclave Operating Strategy
Pueblo Viejo and Woodgrove worked together to compile
a world-class control strategy, integrating diverse technical
insights from team members. These insights illuminated
the intricate nature of autoclave operations and guided the
formulation of a control strategy that embraces the unique
characteristics of the autoclaves rather and adapting to the
“reality” on the ground. For example, due to the nature of
an autoclave, the temperature probe within the autoclave
which measures the temperature of each autoclave com-
partment, can suffer from severe scaling issues and there-
fore the value of the measurement can become unreliable.
However, the rate of change of the measurement provided
by the temperature probe is still representative. Therefore,
control logic was designed to utilize these measurements
prior to scale build-up, and as the temperature value
became unreliable, the logic would switch from controlling
the autoclave compartmental temperature directly to using
a combination of the autoclave vent temperature and the
rate of change of the temperature of the compartment in
question.
The resulting strategy was reviewed with everyone
involved in the Pueblo Viejo operation to generate buy-
in from each operator and formed the basis of the new
control philosophy to be integrated at Pueblo Viejo. This
control philosophy included compartmental ratio control
for the oxygen injection, HPCW injection, and control-
ler prioritization (Feed Flow, oxygen injection, and HPCW
injection) based on the state of each measured variable in
the autoclave (compartmental temperature, autoclave vent
temperature, vent valve opening, autoclave pressure, etc).
To ensure the agreed-upon control strategy aligns
with optimal measured variable targets, a comprehensive
data analysis was conducted. This analysis determined the
optimal control range for all measured variables, ensuring
effective autoclave control. The integration of this refined
strategy and the results from the data analysis formed the
foundation for achieving operational excellence at Pueblo
Viejo.
The technology hierarchy used for the implementa-
tion of the optimization roadmap is shown in Figure 4. The
journey toward operational excellence began with a strong
foundation in the core process. From there, the strategy
focused on utilizing the currently installed instrumenta-
tion, established stabilization measures, and then worked
to optimize the operation.
Step 3—Stabilization
By controlling the oxygen injection per compartment, the
system was able to move oxygen between compartments
to manage increasing or decreasing temperatures within
compartments while not significantly impacting other
autoclave parameters such as autoclave pressure and main-
taining stability within the autoclave. However, the logic
also allowed the AwaRE ® APC system to modify the overall
oxygen being added to the autoclave to manage the auto-
clave pressure, vent valve opening, etc. The oxygen would
then be added per compartment to ensure that the target
compartmental oxygen ratio was maintained.
Data from instruments and sensors available in the
autoclave circuit were run in closed-loop control with
Woodgrove PARC ® controllers, which were integrated into
the DCS to stabilize autoclave Feed Flow utilizing the two
high-pressure feed pumps, the oxygen injection points,
and the HPCW injection point controllers. Woodgrove’s
AwaRE ® APC system was installed at the top-most layer
Figure 3. AC150 Vent temperature and valve opening from June 22, 2020, to July 03, 2020
parameters significantly. This partnership aimed to lever-
age both parties’ collective expertise for mutual success and
operational excellence.
Step 2—Autoclave Operating Strategy
Pueblo Viejo and Woodgrove worked together to compile
a world-class control strategy, integrating diverse technical
insights from team members. These insights illuminated
the intricate nature of autoclave operations and guided the
formulation of a control strategy that embraces the unique
characteristics of the autoclaves rather and adapting to the
“reality” on the ground. For example, due to the nature of
an autoclave, the temperature probe within the autoclave
which measures the temperature of each autoclave com-
partment, can suffer from severe scaling issues and there-
fore the value of the measurement can become unreliable.
However, the rate of change of the measurement provided
by the temperature probe is still representative. Therefore,
control logic was designed to utilize these measurements
prior to scale build-up, and as the temperature value
became unreliable, the logic would switch from controlling
the autoclave compartmental temperature directly to using
a combination of the autoclave vent temperature and the
rate of change of the temperature of the compartment in
question.
The resulting strategy was reviewed with everyone
involved in the Pueblo Viejo operation to generate buy-
in from each operator and formed the basis of the new
control philosophy to be integrated at Pueblo Viejo. This
control philosophy included compartmental ratio control
for the oxygen injection, HPCW injection, and control-
ler prioritization (Feed Flow, oxygen injection, and HPCW
injection) based on the state of each measured variable in
the autoclave (compartmental temperature, autoclave vent
temperature, vent valve opening, autoclave pressure, etc).
To ensure the agreed-upon control strategy aligns
with optimal measured variable targets, a comprehensive
data analysis was conducted. This analysis determined the
optimal control range for all measured variables, ensuring
effective autoclave control. The integration of this refined
strategy and the results from the data analysis formed the
foundation for achieving operational excellence at Pueblo
Viejo.
The technology hierarchy used for the implementa-
tion of the optimization roadmap is shown in Figure 4. The
journey toward operational excellence began with a strong
foundation in the core process. From there, the strategy
focused on utilizing the currently installed instrumenta-
tion, established stabilization measures, and then worked
to optimize the operation.
Step 3—Stabilization
By controlling the oxygen injection per compartment, the
system was able to move oxygen between compartments
to manage increasing or decreasing temperatures within
compartments while not significantly impacting other
autoclave parameters such as autoclave pressure and main-
taining stability within the autoclave. However, the logic
also allowed the AwaRE ® APC system to modify the overall
oxygen being added to the autoclave to manage the auto-
clave pressure, vent valve opening, etc. The oxygen would
then be added per compartment to ensure that the target
compartmental oxygen ratio was maintained.
Data from instruments and sensors available in the
autoclave circuit were run in closed-loop control with
Woodgrove PARC ® controllers, which were integrated into
the DCS to stabilize autoclave Feed Flow utilizing the two
high-pressure feed pumps, the oxygen injection points,
and the HPCW injection point controllers. Woodgrove’s
AwaRE ® APC system was installed at the top-most layer
Figure 3. AC150 Vent temperature and valve opening from June 22, 2020, to July 03, 2020