JKMRC Friday morning seminars showcase the latest developments in sustainable mining

  • By Grant Ballantyne GAusIMM, The University of Queensland, Sustainable Mineral Institute, Julius Kruttschnitt Mineral Research Centre

The Julius Kruttschnitt Mineral Research Centre (JKMRC) Friday seminars are an institution to JKMRC staff, students, friends and alumni.

Every Friday before 9 am during the university semester, the car park fills and visitor badges are donned as friends past and present make their weekly pilgrimage to the JKMRC lecture theatre at the Indooroopilly Experimental Mine site. The Friday seminars have a long, proud history of approximately 1500 seminars, starting in 1971 on the lawn by the university mine head frame as the seminar room was being built. Bill Whiten was acting director at that time, while Director Prof Alban Lynch was on a year’s sabbatical leave.

Initially the seminars were primarily given by JKMRC research students reporting on their work. Prof Lynch recalls fondly that the early seminars were lively and there was much animated discussion, and not much has changed in this regard. One of the fiercest inquisitors was the late Ian Morley, former Queensland Government Mining Engineer, who endowed the annual Ian Morley Prize for students at the JKMRC. However, what has changed in recent times is the number of external people attending and presenting, which has benefited the depth of discussion afterwards. The seminars give the students an opportunity to hear leading practitioners talk about their work, and provide an incentive for some lateral thinking on the issues of the day.

I had the honour of organising last semester’s seminar series. I started off with a wish list of people that I really wanted to hear present and was extremely surprised and gratified by the number of positive responses. It is an indicator of the high esteem in which the Friday seminars are held by many in the industry. With the centre being part of the Sustainable Minerals Institute at the University of Queensland, the mineral processing topics were interspersed with geology, mining and some more wide-reaching presentations. The list of presenters and the titles of their presentations is included below:

Presenter Title
Prof Jean-Paul Franzidis, University of Cape Town Remembrance of things past—and a pique into the future
Prof Peter Knights, School of Mechanical and Mining Engineering, UQ Why don’t more mines use In-Pit Crushing and Conveying Systems?
Greg Lane, Ausenco Engineering and design implications in comminution circuit selection
Bill Whiten, JKMRC (JKMRC alumnus) Aristarchus – Mathematician and Astronomer
Luke Keeney, CRC ORE (JKMRC alumnus) Grade Engineering at Los Bronces: An example of CRC ORE’s Innovation Pathway
Steve Morrell, SMC Testing (JKMRC alumnus) Evaluation of the Energy Efficiency of Comminution Circuits
Kym Runge, JKMRC (JKMRC alumnus) Integrated grinding and flotation simulation
Ben Bonfils, JKMRC Meaningful measurement of rock impact strength: Linking rock composition, alteration, and damage to processability
Juan Jose Frausto Gonzales, JKMRC Technical Audits of three Fresnillo & Peñoles plants in Mexico
Joe Pease, Mineralis Crossing the Innovation Valley of Death
John Jackson, JKTech Ore Type: Everything to someone but… nothing to anyone
Travis Murphy, Bryan Research Centre Beyond (and Before) Rock Mass Characterisation – The Impact of Geology on Block Cave Mining
Mal Lees, Independent (JKMRC alumnus) Bougainville Crushing Plant Performance Improvement — The ‘Why? and How’
Prof TC Rao, ‘the father of Indian mineral processing’ (JKMRC alumnus) Mineral (Processing) Industries: A Holistic View – T.C. Rao’s Perceptions. (introduction by Prof. Lynch)
Prof Malcolm Powell, JKMRC Integrated Process Prediction

 

10 of these presenters have allowed their presentations to be published publically on the JKMRC YouTube account, together with many presentations given in previous semesters. If you would like to review these presentations yourself please visit our website www.youtube.com/user/smiuq. To whet your appetite, my summaries of this semester’s presentations are included below.

Greg Lane presented a very interesting account of the design of capital sensitive comminution circuits that leverage natural contours, have low footprint, low height and use less concrete, steel and piping. This style of design is an iterative process that involves the challenge of listening and aligning to customer’s specifications, developing trust and delivering. He explained that one of the failings of engineering companies is that they all have their own paradigms and formulas and can only achieve as much optimisation as the budget will allow.

A summary of the activities of CRC ORE was presented by Dr Luke Keeney, concentrating on the results that were obtained from the recent site study at Los Bronces. His team found that they achieved great results by embedding researchers and site personnel into project teams where 80 per cent of their job is delivery on the project.

Dr Steve Morrell ventured back to the JKMRC to give a fantastic summary of his approach to the evaluation of energy efficiency of comminution circuits. He went back through the history such as his 1991 AusIMM Mill Operators paper that found that a semi-autogenous grinding (SAG) mill circuit could be as energy efficient as a crushing/ball mill circuit. He also told of his finding that open circuit milling had a much higher Bond Operating Work index (OWi) than closed circuit milling, not because of differences in energy efficiency but due to fundamental problems with Bond’s equation. He explained that within the accuracy of the results, his method found no significant difference between the energy efficiency of different tumbling mill circuits when they were well run.

Dr Kym Runge discussed the effect that changes in the mineral size distribution have on flotation recovery. The presentation made clear that the overall mass size distributions (that comminutors consistently use) are not a good measure of mineral size distributions, which are integral to flotation performance. Her rule of thumb was that a 10 μm increase in P80 typically reduces recovery by one per cent, but that this was only seen on site, not in the laboratory. She observed that coarse particle recovery regularly dropped off with the addition of ultra-fines, possibly due to the robbing of reagents by the increased surface area of the fines.

A paradigm shift in the methods of characterisation of rocks for comminution was presented by Dr Benjamin Bonfils. He presented the history and use of the Short-Impact Load Cell (SILC). Using this device he found that there was no significantly difference in the strength of rock prepared by either cut or blast and that the High Pressure Grinding Roll (HPGR) product had the same strength below 1 mm.  He asserted that fines particle breakage is controlled by crack initiation, whereas fracture of coarse particles is dominated by crack propagation. Finally, he presented a methodology for breaking mini-core samples that reduced variance in the results by 1/10th and allowed the real difference between populations of rocks to be measured accurately.

Juan Jose Frausto Gonzalez (a JKMRC student) presented a summary of the recent study trip that a team of JKMRC students took to Mexico. Juan was inspired by Prof Lynch to use his contacts at Peñoles and Fresnillo to accept six students to conduct surveys at three of their mines. This was a great example of technology transfer and training between PhD students and site operators, and is a format that will be followed into the future. Juan described the measurements that were taken at Minera Saucito mine. He showed that when high-frequency (Derrick) screens are installed in place of hydrocyclones, an increase in throughput and lead recovery was measured, but silver recovery dropped significantly. This was found to be due to differences in the size-by-recovery in flotation and differences in the mineral and bulk size distributions due to the density bias that occurs in a cyclone.

In his typically engaging way, Joe Pease presented his experiences in ‘crossing the innovation valley of death’. His experiences were drawn from the many innovations that were progressed while he worked at Xstrata Technology. Of those he discussed details behind the IsaMill, Jameson cell, and IsaSmelt technologies. He stressed that if the minerals industry appears conservative it is because it is highly interconnected, complex and risky. Innovators need to find way to reduce risk rather than increase it. He highlighted that even simple changes can be highly disruptive – even a simple screen to remove low grade coarse waste (ie Grade Engineering™) has disruptive effects on materials handling and ore flow unless carefully designed with operators. We were reminded that maintenance, operability and KPIs always win. And he left us with seven key conditions for innovation: driving need, designed for your ore, passionate champions, bite-sized implementation, simple Intellectual Property (IP), high quality ongoing support and enabling organisation systems.

The presentation given by Dr Mal Lees was a retrospective analysis of the Bougainville crushing circuit. The Bougainville story is one that has fascinated many within the mining industry and this was another chapter that is not often presented. Over a number of years, the team responsible for the crushing plant was able to achieve 92 per cent utilisation. This was a breath of fresh air in a world where crushing operations expect utilisation rates of around 75 per cent. His simple mindset of maximising power utilisation and then deciding on the specific energy to achieve a grind size and recovery was very elegant and successful.

The best-attended event of the year was when Prof TC Rao came to present his holistic view of mineral processing industries. Prof Rao was the second student to graduate with a PhD from the JKMRC in 1966 and subsequently has gone on to do great things back in India where he is affectionately known as ‘the father of Indian mineral processing’. He was in Australia to receive the University of Queensland’s International Alumni of the Year award and we took advantage of this and asked him to present a Friday seminar. The presentation turned into a great event; I don’t think there was a spare seat as many of the JKMRC alumni came out to celebrate (see photo below). His presentation was very insightful bringing together community needs and expectations together with the industry requirements. His holistic approach combined the needs of all the stakeholders: mining, environment, community and biodiversity.

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The audience at Prof TC Rao’s presentation, including former JKMRC Director Prof Alban Lynch.
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Prof T C Rao presenting at the JKMRC Friday morning seminar.

Finally, the last presentation for the year was given by Prof Malcolm Powell who presented his vision for integrated process prediction. His presentation distilled the thinking about uniting our understanding down the whole value chain. His hypothesis is that the information we need to break down the current silos is all present in the rock. He suggests that our current use of proxy characterisation methods are clouding our perceptions and limiting our ability to integrate. And he finished by presenting the tools and capabilities that are currently being developed in the JKMRC to achieve this goal.

In addition to the Friday seminars, Prof Tim Napier-Munn delivered the Brisbane version of his extremely interesting AusIMM Delprat lecture at the JKMRC. In this he discussed the hypothesis that innovation is not optional, it is critical to our business, and in the past the mineral industry has innovated rather well. However, forces are gathering that will make innovating in the industry more difficult in the future, and he laid out a strategy for dealing with these problems. This talk is also available through the JKMRC YouTube account.

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