6
advantage of installing duty-only equipment is essentially
the simplicity and cost-effectiveness of the design.
A grinding circuit availability analysis was conducted
for duty-standby and duty-only cyclone feed pumps
(Figure 6). The net benefit of duty-standby cyclone feed
pumps over duty-only feed pumps is 0.2%, an additional
20 hours of maintenance time saved in a year. The overall
maintenance cost saving is marginal compared to capital
cost saving, thus impacting the net present value.
To compensate for the marginally lower availability of
duty-only cyclone feed pumps, the feed rate to the grind-
ing circuit can be increased by 0.2%, which would incur
an additional 1.2% in direct costs of all major equipment
in the process plant due to resizing. A flowsheet with a
duty/standby cyclone feed pump could be cost-effective.
However, it can succumb to line sanding issues and inop-
erable valves at startup, offsetting the 0.2% availability
advantage over duty-only cyclone feed pumps. Therefore,
duty-standby cyclone feed pumps require proactive main-
tenance and operating strategies.
In flowsheet design, ease of maintenance access should
be considered for duty-only pebble crushers to minimize
maintenance downtime. Table 5 presents the advantages of
duty only vs duty standby pebble crushers in the grinding
flowsheet. For planned maintenance of duty-only pebble
crushers, finer or less competent feed to the SAG mill could
be scheduled in the mine plan. This would require careful
integration of the mining practice with maintenance objec-
tives to meet production targets.
SOLUTIONS TO INCREASE THE
AVAILABILITY OF EQUIPMENT
Maintaining effective working equipment requires a com-
bination of preventative maintenance leveraged by pre-
dictive insights gained from online monitoring (Table 6).
Successful operations rely on an experienced maintenance
team to continuously monitor critical assets to minimize
unexpected downtime.
Several commercial online solutions are available to
assess the asset’s performance and provide continuous diag-
nostics of critical components. The data output can then be
incorporated into machine learning algorithms to improve
the predictability of failure, increasing the equipment’s
availability enabled by insight-driven maintenance plan-
ning (Chandramohan, 2023 &2024).
Besides improving maintenance strategies to increase
equipment availability, OEM (original equipment manu-
facturer) and engineering companies are developing several
smart solutions to minimize downtime during maintenance
and replace worn components.
For example, different maintenance approaches can
reduce downtime for cyclone feed pumps. Weir Minerals
has estimated the time taken to replace the worn compo-
nents in the slurry pump based on the type of maintenance
strategy (Table 7). Shifting the maintenance strategy from
in-situ to bare shaft assembly can reduce the downtime by 8
hours. The maintenance cost incurred is higher for the bare
shaft than the in-situ strategy, as a complete pump assembly
is required for replacement. Compared to production lost
time, the trade-off for a new pump assembly is insignificant
as production lost time significantly impacts the overall
project net present value (NPV).
High-wear components in bulk handling, such as
transfer points and chutes, can be replaced with refurbished
sections or rotable spares. To accommodate ‘ease of lift’, all
sections of the rotable component must be engineered to
suit the type of crane used for maintenance. Due to the
90-degree transfer point to the SAG mill feed chute in Phu
Kham, a deflector liner plate requires frequent replacement
(Figure 7).
Figure 6. Equipment availability benefit analysis on the overall grinding circuit availability
(Analysis conducted by Ausenco’s Asset Optimisation Team)
advantage of installing duty-only equipment is essentially
the simplicity and cost-effectiveness of the design.
A grinding circuit availability analysis was conducted
for duty-standby and duty-only cyclone feed pumps
(Figure 6). The net benefit of duty-standby cyclone feed
pumps over duty-only feed pumps is 0.2%, an additional
20 hours of maintenance time saved in a year. The overall
maintenance cost saving is marginal compared to capital
cost saving, thus impacting the net present value.
To compensate for the marginally lower availability of
duty-only cyclone feed pumps, the feed rate to the grind-
ing circuit can be increased by 0.2%, which would incur
an additional 1.2% in direct costs of all major equipment
in the process plant due to resizing. A flowsheet with a
duty/standby cyclone feed pump could be cost-effective.
However, it can succumb to line sanding issues and inop-
erable valves at startup, offsetting the 0.2% availability
advantage over duty-only cyclone feed pumps. Therefore,
duty-standby cyclone feed pumps require proactive main-
tenance and operating strategies.
In flowsheet design, ease of maintenance access should
be considered for duty-only pebble crushers to minimize
maintenance downtime. Table 5 presents the advantages of
duty only vs duty standby pebble crushers in the grinding
flowsheet. For planned maintenance of duty-only pebble
crushers, finer or less competent feed to the SAG mill could
be scheduled in the mine plan. This would require careful
integration of the mining practice with maintenance objec-
tives to meet production targets.
SOLUTIONS TO INCREASE THE
AVAILABILITY OF EQUIPMENT
Maintaining effective working equipment requires a com-
bination of preventative maintenance leveraged by pre-
dictive insights gained from online monitoring (Table 6).
Successful operations rely on an experienced maintenance
team to continuously monitor critical assets to minimize
unexpected downtime.
Several commercial online solutions are available to
assess the asset’s performance and provide continuous diag-
nostics of critical components. The data output can then be
incorporated into machine learning algorithms to improve
the predictability of failure, increasing the equipment’s
availability enabled by insight-driven maintenance plan-
ning (Chandramohan, 2023 &2024).
Besides improving maintenance strategies to increase
equipment availability, OEM (original equipment manu-
facturer) and engineering companies are developing several
smart solutions to minimize downtime during maintenance
and replace worn components.
For example, different maintenance approaches can
reduce downtime for cyclone feed pumps. Weir Minerals
has estimated the time taken to replace the worn compo-
nents in the slurry pump based on the type of maintenance
strategy (Table 7). Shifting the maintenance strategy from
in-situ to bare shaft assembly can reduce the downtime by 8
hours. The maintenance cost incurred is higher for the bare
shaft than the in-situ strategy, as a complete pump assembly
is required for replacement. Compared to production lost
time, the trade-off for a new pump assembly is insignificant
as production lost time significantly impacts the overall
project net present value (NPV).
High-wear components in bulk handling, such as
transfer points and chutes, can be replaced with refurbished
sections or rotable spares. To accommodate ‘ease of lift’, all
sections of the rotable component must be engineered to
suit the type of crane used for maintenance. Due to the
90-degree transfer point to the SAG mill feed chute in Phu
Kham, a deflector liner plate requires frequent replacement
(Figure 7).
Figure 6. Equipment availability benefit analysis on the overall grinding circuit availability
(Analysis conducted by Ausenco’s Asset Optimisation Team)