The use of trend based mineralogy in continuous process improvement

The analysis of daily composite samples forms the core component of any operational mineralogy program.  This provides a snapshot of the daily activity in the processing plant and will generate a step change in the level of understanding of the drivers for process performance as well as provide site personnel with a valuable tool for decision making.  To generate the maximum value from routine mineralogical data daily composite data can be used to create data trends over time in order to monitor process response, rather than just snapshots in time.

Figure 1 – Variation in copper mineralogy with time for flotation final concentrate from copper mine

The mineralogical trend information is built from daily composites, which are aggregated into weekly trend data composites and subsequently monthly trend data composites.  Assessing mineralogical trends on daily composites can allow rapid development of a process baseline, from which any fluctuations can flag that there may be an issue.

Trends generated from daily mineralogical analysis are the backbone of generating value from operational mineralogy.  They form the basis of the continuous improvement matrix and allow for fast identification of potential process issues or improvement areas.  In this way the use of trend base mineralogy forms one of the key points of difference in using high-frequency but low resolution mineralogical information for operational decision support.

Trend mineralogy provides a tool to cut through operational noise.

Trend data reduces the noise associated with natural ore variability and more easily identifies when negative process conditions are occurring.  This becomes a powerful tool in integration of mineralogy information into the day-to-day operation of a mineral processing circuit.  It allows for differentiation between ore variability effects and genuine changes in process performance, which in turn improves efficiency in driving resources to address the projects with most value generating potential for the operation.

Trend mineralogy drives day to day decision support.

As trend-based mineralogical datasets are established to a level where process parameters can be related to the mine plan, the information can then be integrated into day-to-day decision-making, providing a powerful tool for operators to make more informed decisions.  This can then be extended to the holy grail of better forecasting and reconciliation, where process forecasting can be based on fundamental material behaviour rather than a simple extrapolation of assumptions based on grade.  Finally, given sufficient data quality, the data may be used in preventative maintenance planning through early identification of process changes that are unrelated to ore characteristics.

Figure 2 – Trend mineralogy for 1 week of feed to leach circuit from copper mine

For example, the data presented in figure 2 shows a week of consistent feed to a copper leach circuit.  On day 6 a spike in acid insoluble copper minerals was observed, along with a reduction in acid consuming gangue.  Related back to the process behaviour this resulted in a drop in copper recovery in the leach but with lower overall acid consumption offsetting some of the lost revenue.  In this case, by relating the material to the mining feed it was possible to identify that on that day material from a stockpile had been blended with the planned ore.  This is a great example of where an unplanned change in the feed material had direct impact on copper recovery.  Without relationship of the trends the cause of the day of poor performance would have been much harder to diagnose and would have required significantly more resources to establish the same answer.

One of the primary benefits of implementing operational mineralogy to obtain daily mineralogy information for a process circuit is the mineralogical trends that can be established.  While by necessity the information generated is lower resolution than we may be used to in mineralogical analysis the use of this information for generation of trends gives an extremely powerful tool to both quickly identify valuable opportunities and relate information from other datasets.

If you have any questions feel free to contact us directly or touch base with iMin Solutions.  Also if you are interested in finding out more about process mineralogy make sure you download our digital book, which gives some more details on how to build mineralogical capability and start getting real value for your investment