Every mine owner knows that the comminution process costs the most in CapEx and OpEx like no other part of the business. It can also be the leading contributor to a minerals processing plant’s carbon footprint. With focus now shifting to environmental and financial sustainability, many mine owners and investors are asking if there are better ways to conduct comminution. At Ausenco, we firmly believe there are.
In a recent webcast hosted by AusIMM, three of our top technical professionals explored the relationship between comminution, energy consumption, resource use and environmental risk. They highlighted the influence comminution has on the safety and efficiency of tailings management. And they talked about reducing the amount of energy and water needed for the comminution process.
What did they say?
Much of the webcast was spent exploring three key trends that are driving new approaches to comminution across the mining sector.
- Greg Lane, Chief Technical Officer, shared some metrics on the cost, energy requirements and environmental impact of traditional SAG mills. He then compared a range of existing autogenous milling techniques – such as Vertical Roller Mills, High Pressure Grinding Rolls and Autogenous (AG) milling – and their flowsheets to SAG milling to show the potential upside of the different approaches (spoiler alert: AG milling far outperforms SAG milling in terms of operating cost and CO2 production). In his discussion, Greg offered a practical view of some of the constraints, opportunities and advantages of AG milling with a specific view on reducing Scope 3 carbon emissions.
- Bianca Foggiatto, Technical Director of Comminution & Processing, discussed the increasing application of stirred milling, particularly in coarse duty applications. She shared a number of examples of operating mine sites where stirred milling technologies are being used for regrinding duties to improve overall energy efficiency. She discussed how supporting technologies like Coarse Particle Floatation (CPF) can help drive additional cost, safety and environmental improvements. And she explored some of the factors that can influence the energy efficiency of stirred milling applications – such as regrind feed particle size distributions and media size selection.
- Grant Ballantyne, Director of Technical Solutions, got down into the science of comminution energy efficiency with a look at his recent research into fractal theory. In his discussion, Grant explained how fractal theory can be used to unite a number of existing and standard laws (such as Bond’s Law and Morrell’s Law) that engineers currently use to estimate comminution energy usage. His findings are expected to have a significant impact on the way mine executives and design engineers plan for new comminution processes in the future, particularly as energy costs rise and regulator scrutiny on the resources sector increases.
Answering the key questions
With more than 100 live attendees participating in the webcast, the team spent some time answering a range of audience questions. Watch the webcast to find out Ausenco’s leaders views on:
- The comparative efficiency of AG milling as a function of ore hardness
- The types of test work required on drill core to assess the suitability of AG milling
- The impact of stirred milling
- Which mill types to select in an open circuit when considering stirred milling
- How fractal theory can help to specify equipment for a particular duty
Get the full scoop
To learn more about the emerging opportunities to significantly enhance the carbon intensity of comminution, we encourage you to watch the recent AusIMM webcast or contact one of our industry leaders.