The latest developments in preconcentration: expert Q&A
AusIMM, in conjunction with CRC ORE, is hosting the inaugural Preconcentration Digital Conference in November 2020. In the lead up to the event, the AusIMM Bulletin spoke to conference committee members Gavin Yeates and Ben Adair to find out more about the conference and the latest developments in preconcentration.
What do we mean by preconcentration?
Gavin Yeates (GY): Preconcentration covers the approaches that can be used to increase ore grades through the selection of valuable material and rejection of material carrying little or no value prior to final stage processing. The result is that waste material is rejected prior to large consumption of energy, water and production of fine wastes (tailings), hence providing a cheaper and more sustainable overall outcome.
Preconcentration brings processing closer to the mine face and is carried out at coarse size fractions. Preconcentration covers geometallurgy and the characterising of orebodies for mineralogy, heterogeneity and uncertainty; blasting to differentiate valuable material from waste; selective mining and then the progressive sorting of ore feeds. This is done using either natural deportment or sensor-based bulk ore sorting, through to particle sorting combined with selective breakage through crushing and grinding circuits.
This is a brand new conference – why is now the right time to be talking about preconcentration?
GY: This conference has been held as a closed event for CRC ORE participants in previous years. Because the term of CRC ORE is coming to an end, their findings and advances are now ready to be publicised to a wider audience.
At the same time, interest in ore sorting and preconcentration has risen due to advances in sensing and some very successful applications. In addition, orebody grades are dropping and energy, water and tailings footprints for mines are increasing with societal pressures driving different approaches to mining and processing.
What role does preconcentration play in reducing the amount of mine waste and tailings?
Ben Adair (BA): Preconcentration technologies have a key role in changing the nature of mine waste and tailings. In my experience, around one third of orebodies are highly amenable to gangue rejection technologies, one third can be made amenable and one third will never respond.
For those that are amenable, the role of preconcentration is to reject waste at coarse sizes before resource intensive processing. The overall mass (not volume) of mine waste normally stays the same with preconcentration, but it is preserved in a more sustainable form.
What’s the best way to ensure preconcentration approaches are integrated into mine planning right from the start?
A full range of stakeholders need to be aware of both the potential and actually realised benefits of preconcentration. This includes boards, financiers, regulators, community groups and other social licence stakeholders.
We now have highly effective predictive protocols to accurately define the potential of preconcentration in ore domains at any given operation. These predictive indices can be incorporated seamlessly into block models, mine planning and extraction sequencing. If implemented properly, preconcentration affords existing sites significant uplift potential in productivity, water and energy use. It also provides the opportunity to reveal ‘hidden value’ in M&A activity.
One of the focus areas at the conference will be case studies of success stories. Are there any noteworthy recent examples of the business benefits of applying preconcentration techniques?
GY: Yes, there are significant case studies at full scale now available from both CRC ORE participants and from companies who have applied preconcentration techniques.
There are examples of success including natural deportment (screening), sensor based bulk ore sorting and sensor based particle sorting. There are also now enough trial studies that provide mines looking to apply preconcentration a variety of options and significant learnings on methods, scale up and deployment in the field.
BA: I have reviewed a number of papers submitted to the conference and they are replete with case study examples across a number of preconcentration technologies and commodity sites. Several of these also articulate substantial financial benefits. Of key importance in realising such benefits is integrating outputs from the technologies with the existing control systems across the value chain. I think the delegates will find the financial impacts associated with the case studies quite revealing.
How can we get a higher level of collaboration between research bodies and industry when it comes to developing and implementing preconcentration technologies and techniques?
GY: Cooperative research centres (CRCs) have been a great way for industry and researches to collaborate and tackle some of the bigger and more challenging issues facing the mining industry. A CRC provides the scale to take a research idea from the laboratory to the field. More CRCs are needed in the mining industry, but this requires the sector to lead this by coming together and clearly defining the challenges they are facing, so that researchers can then align on those challenges.
BA: Co-development partnerships are the key to success. When executed properly, prototype development and validation can be progressed very rapidly through partnerships between vendors and end users – at least twice as fast as the convention when technology is progressed by a single vendor in isolation.
The same applies to inventors in the research community. The development of co-creation partnerships between research institutions, the vendor (who has the expertise to build a robust prototype) and a mining company, provides an ‘implementation pathway’ for new innovations. Having an end user involved not only provides potential investment to fast track development, it also potentially provides site availability to test and validate the innovation.
Unfortunately, there are many examples of researchers working in isolation whose highly promissory inventions lie unused for many years.
Is there a particularly exciting technique or technology that you’re looking forward to hearing more about at the conference?
GY: The conference will cover a number of advances in sensor development and application. The use of sensors in novel applications to detect details in a bench prior to mining and determine the grade in a truck are some of the novel applications that are of interest. Also understanding how to carry out sensor tests and how to calibrate sensors in the field, moving beyond the manufacturer specifications to understand the learnings from people who have experienced actual application.
BA: Preconcentration technologies in the past failed to get significant traction in the industry in large part due to vendors selling single ‘point solutions’. But there is no ‘silver bullet’ technology to effect significant gangue rejection; our experience is that it is the integration of data fusion from multiple sensors that leads to more efficient separation and exploitation of mineral heterogeneity. The conference has numerous papers illustrating the power of this integration. I am looking forward to learning more about the efficacy of combining leading edge techniques where the outcome summation is greater than the individual parts.