XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 995
to act as a global optimizer. AwaRE ® consists of a heuristic
model with a fuzzy-logic core and an inference engine and
is used to automate the site’s best operating practices devel-
oped for Pueblo Viejo. The implementation of the various
layers of technology ensured that process stability was sus-
tained for extended periods of time. With the improved
stability, the circuit could then be optimized.
The AwaRE ® APC system was able to optimize the pro-
cess while maintaining stability in the autoclave by choos-
ing the most effective method to handle each situation. For
example, by controlling the oxygen injection per compart-
ment, the system was able to move oxygen between com-
partments to manage increasing or decreasing temperatures
within compartments, while not significantly effecting
other autoclave parameters such as autoclave pressure and
maintaining stability within the autoclave. However, the
logic also allowed the AwaRE ® APC system to modify the
overall oxygen being added to the autoclave when required
(e.g., to manage the autoclave pressure, vent valve opening,
vent temperature etc.). The oxygen would then be added
per compartment to ensure that the target compartmental
oxygen ratio was maintained.
One major constraint which was identified early in
the integration was that the autoclave level would often
increase above the desired range which would then result
in a decrease in feed flow to the autoclave. However, a
self-regulating mechanism was recognized. By intention-
ally increasing the overpressure within the autoclave,
excess material would be expelled, naturally lowering the
autoclave level to the desired range without the need for
reducing throughput. Therefore, prior to decreasing feed
flow, APC logic was configured to allow the overpressure
to be increased slightly to ensure it was still within the tar-
get range, but high enough to result in the self-regulating
action in decreasing the autoclave level.
Step 4—Optimization &Training
The final step in Pueblo Viejo’s autoclave optimization cam-
paign was control system tuning and personnel training.
Training provided all personnel with the ability to clearly
understand the AwaRE ® system actions allowing each per-
son to highlight improvement opportunities and provide
valuable feedback on the system performance. Woodgrove
and the Pueblo Viejo team then worked together to update
the agreed upon control strategy according to this feed-
back. Once the integration was complete, the Pueblo Viejo
operations team was able to confidently utilize the AwaRE ®
APC system to realize the quantifiable benefits envisioned
during step one of the process.
SAFETY—WHY THE PROJECT
SUCCEEDED
Pueblo Viejo is a large operation and due to the nature of
remote integration, each step was taken cautiously with all
stakeholders involved in all communication. The Pueblo
Viejo operations team provided many valuable notes dur-
ing remote integration. These notes led to the development
of several safety rules in the AwaRE ® APC system to pro-
tect the autoclave from events such as agitator tripping,
oxygen bubble buildup, and overpressure risks. Autoclave
Instrumentation
LIT, FIT, TIT, PIT, Valve Feedback
Unit Process (Autoclaves)
Optimizer
Stabilization Algorithms
Figure 4. APC integration philosophy
to act as a global optimizer. AwaRE ® consists of a heuristic
model with a fuzzy-logic core and an inference engine and
is used to automate the site’s best operating practices devel-
oped for Pueblo Viejo. The implementation of the various
layers of technology ensured that process stability was sus-
tained for extended periods of time. With the improved
stability, the circuit could then be optimized.
The AwaRE ® APC system was able to optimize the pro-
cess while maintaining stability in the autoclave by choos-
ing the most effective method to handle each situation. For
example, by controlling the oxygen injection per compart-
ment, the system was able to move oxygen between com-
partments to manage increasing or decreasing temperatures
within compartments, while not significantly effecting
other autoclave parameters such as autoclave pressure and
maintaining stability within the autoclave. However, the
logic also allowed the AwaRE ® APC system to modify the
overall oxygen being added to the autoclave when required
(e.g., to manage the autoclave pressure, vent valve opening,
vent temperature etc.). The oxygen would then be added
per compartment to ensure that the target compartmental
oxygen ratio was maintained.
One major constraint which was identified early in
the integration was that the autoclave level would often
increase above the desired range which would then result
in a decrease in feed flow to the autoclave. However, a
self-regulating mechanism was recognized. By intention-
ally increasing the overpressure within the autoclave,
excess material would be expelled, naturally lowering the
autoclave level to the desired range without the need for
reducing throughput. Therefore, prior to decreasing feed
flow, APC logic was configured to allow the overpressure
to be increased slightly to ensure it was still within the tar-
get range, but high enough to result in the self-regulating
action in decreasing the autoclave level.
Step 4—Optimization &Training
The final step in Pueblo Viejo’s autoclave optimization cam-
paign was control system tuning and personnel training.
Training provided all personnel with the ability to clearly
understand the AwaRE ® system actions allowing each per-
son to highlight improvement opportunities and provide
valuable feedback on the system performance. Woodgrove
and the Pueblo Viejo team then worked together to update
the agreed upon control strategy according to this feed-
back. Once the integration was complete, the Pueblo Viejo
operations team was able to confidently utilize the AwaRE ®
APC system to realize the quantifiable benefits envisioned
during step one of the process.
SAFETY—WHY THE PROJECT
SUCCEEDED
Pueblo Viejo is a large operation and due to the nature of
remote integration, each step was taken cautiously with all
stakeholders involved in all communication. The Pueblo
Viejo operations team provided many valuable notes dur-
ing remote integration. These notes led to the development
of several safety rules in the AwaRE ® APC system to pro-
tect the autoclave from events such as agitator tripping,
oxygen bubble buildup, and overpressure risks. Autoclave
Instrumentation
LIT, FIT, TIT, PIT, Valve Feedback
Unit Process (Autoclaves)
Optimizer
Stabilization Algorithms
Figure 4. APC integration philosophy