Using process knowledge, experience and data to optimise complicated comminution circuits

By Rajiv Chandramohan, Senior Process Engineer, Business Improvement and Comminution Consultant

In today’s challenging market conditions, owners and operators of mining operations are searching for new strategies and sustainable practices to maximise throughput and productivity. When operations are particularly complicated processes with multiple ore types and a number of grinding circuit- configurations, the many variables involved can make this an even greater challenge.

On one recent project, the comminution circuit of a gold plant included treatment of five different ore types, a large oxygen production plant and four large autoclaves, creating more than 50 options to choose from every day in operating the circuit. Our client sought our help to identify throughput limiting constraints and to develop and help implement operational strategies to maximise productivity as a member of their owner’s team. With so many variables, gathering and reviewing data, accessing and interpreting the knowledge from Ausenco’s comminution and process experts and the use of technology and tools for options, scenario planning and real-time tracking of data were essential. One of the tools developed was our “mine to mill to metal” optimiser which uses daily ore scores and machine characteristics to determine the likely production outcomes. Data was benchmarked to calibrate the various process models used in the predictive algorithms.

Close collaboration with and training of the onsite project team were also important elements of this ongoing optimisation process – for true sustainability it was important that the team understood the data they were viewing, the targeted benchmarks and the options for all the variables to ensure continual improvement. Through this approach, and two years into a five year process, production has already increased by 30%.

Another close collaboration success story is the one we’ve developed between Ausenco’s technical team and Pan Aust’s Phu Kham Copper Gold Operation.

Ausenco was engaged to help optimise and increase the productivity of the Phu Kham operation from December 2016 to May 2017. The work involved participating in the redesign of the SAG mill liner systems to maximise throughput; implementation of comminution optimisation strategies for the treatment of harder ores and coordinating with the mining, process and maintenance teams to achieve productivity above the original design name-plate capacity. We used a combination of technical experience, data analytics and onsite team development to achieve the outcomes

As part of the technical service, we used our powerful comminution optimisation tool, Ausgrind, which uses 30+ years data to benchmark and analyse real-time plant data with empirical models, predict circuit performance for varying ore characteristics and evaluate liner wear and life prediction for varying operating machine parameters.

Variances between the actual and the predicted values were technically assessed in detail to identify missed opportunities and operating parameters redefined to maximise throughput and productivity. Using this data and the combined Ausenco/Pan Aust teams’ experiences we were able to determine the optimal operating parameters required to maximise the entire comminution circuit and mining methods. Implementation of these changes is on ongoing work in progress; however initial outcomes indicate a substantial increase in throughput has been realised.

For more information on our comminution services, click here or contact Rajiv.

Image shown above is Pan Aust's Phu Kham project in Laos.