Monday, 8 September 2014

Towards the next generation of mineral processing plants

These are exciting times in mineral processing. Probably not since the development of froth flotation has there been such intensive debate on the need to focus on a specific area for research. Reduction in energy consumption has to be the major thrust of future mineral processing research, particularly in respect to comminution machines and circuits.

A recent Canadian paper in Minerals Engineering introduces an energy benchmarking model for mineral comminution for assessing the energy performance of different crushing and grinding technologies. In the same volume researchers from Australia's JKMRC surveyed the comminution energy requirements of gold and copper producing mines  to provide reliable benchmarking data which can be used to compare comminution energy consumption across different mine sites. The study showed that comminution of gold and copper ores can be expected to consume about 0.2% of global, and 1.3% of Australia’s electricity consumption.  Analysis of the contribution of circuit efficiency, ore competence, grind size and ore grade showed that ore grade was the greatest determinate of specific comminution energy.

The best way to reduce comminution energy is not to comminute, therefore concentrating the ore via gangue rejection prior to grinding is likely to achieve the largest positive effect on comminution energy efficiency. Dense medium separation has long been used to do this on amenable ores, such as Pb-Zn vein deposits, but electronic ore sorting is showing great potential, by identifying the metal values in a run-of-mine stream and separating the rock containing valuable mineralization from barren material. This branch of technology has been the subject of papers at virtually every recent mineral processing conference, and will be the subject of Dr. Rob Morrison's keynote lecture at Physical Separation '15 next June.  Another Canadian paper in Minerals Engineering provides quantitative discussion on the impact of this technology. Dual-energy X-ray transmission was used to sort ore from different mines, and an analysis identifying the economic impact of these results presented.  Ore sorting has been identified as a technology with potentially broad reaching impacts on the mining industry. With the implementation of ore sorting significant energy savings or throughput increases are realized during comminution, and these effects are then felt throughput the plant.

Another technique which I am sure we will hear more of is gangue rejection within the comminution circuit via coarse flotation in fluid-bed separators, such as the Eriez HydroFloat separator (see posting of 5 August 2013).

In our recent conversation, Prof. Alban Lynch felt strongly that mineral processing in the future needs to be linked to mining. As early as 1975 the JKMRC extended their comminution modelling research to blasting because that was the first in the sequence of size reduction processes. The feasibility study was carried out with support from Mount Isa and Mount Newman and the blasting project became a large and long running AMIRA project. The research was very useful to blasting engineers but it was many years before the link between blasting and crushing and grinding was developed.

It is interesting that this year's Coalition for Eco-Efficient Comminution (CEEC) Medal has been awarded to Orica’s Dr. Geoff Brent and his research team for ground-breaking research using a novel method of Ultra-High Intensity Blasting to improve mine productivity. Orica Managing Director Ian Smith said the quest to use the chemical energy in explosives to improve ore fragmentation and deliver a step change in mine processing efficiency was a priority for the global resources sector. “Independent modelling has indicated that increasing the explosive energy by several fold can lead to increases in mill circuit throughput of up to 40% and savings of tens of millions of dollars annually.”  Speaking on behalf of the research team, Dr. Brent said: “By utilising explosive energy in the pit to produce much finer ore we can dramatically increase the efficiency and throughput of the downstream comminution processes of crushing and milling. The overall energy consumption across the mining and milling cycle can be reduced with a consequent reduction in emissions. This is a step-change in ore processing.”

It has been announced recently that Metso has signed a 5-year strategic research agreement with The University of Queensland's JKTech division to develop next-generation technologies and services for energy-efficient minerals concentration (MEI Online). The agreement is part of a program where Metso and JKTech SPA will cooperate with the leading Chilean mining companies to develop Chile as a regional innovation hub for minerals processing.  The program's four principal research themes are primary grinding, ball mill grinding, classification and coarse particle flotation; the main operational targets are productivity, energy and water efficiency.

"The goal of this unique research program is to take some serious steps forward in the development of equipment and methods that will enable the construction of the next-generation mineral concentrator. A very attractive feature of the program is that each technology offers a retrofit possibility to improve existing plant performance and can be utilized at other mines around the world as well" says João Ney Colagrossi, President of Metso's Mining and Construction (as of October 1, 2014 President, Minerals, Metso).

"We are delighted to partner with Metso in this exciting Program. The 'Next-Generation Concentrator' will provide a step change in the energy, capital efficiency and production signatures of process plants for the global minerals industry.  Our time frames for implementation are aggressive and we look forward to a suite of innovation outcomes for our co-creation industry partners," states Dr. Ben Adair, Deputy Director, Sustainable Minerals Institute at UQ.

It is clear that there are fundamental changes taking place in the approach to mineral processing research and it is our aim at MEI to reflect these forthcoming paradigm shifts in the content of future MEI Conferences.

19 comments:

  1. Don't ignore China! The next generation is already coming from there. In gravity concentration equipment, especially (in my experience small to medium scale third world environments), hard to beat on robustness, simplicity and price. Quality not far off. Once the communication gap is covered, will the west and traditional companies be able to compete? I would never have imagined myself saying this 5 years ago but experience has now shown me different. Design ability is lacking, but if you know what is available and what it can do, and can design from that, why should you pay 3-4 times the price and wait 3-4 times the time for delivery?
    Steve Canby, MinEx Associates, UK

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    1. Sorry Steve but can't agree with china gear being up to the standards our top companies can produce, their gear looks good and is certainly in the right price range as for time delivery it depends on the location., I can't comment on earthmoving gear as it's not my area of expertise but on the process side, the Mills, pumps crushers etc would be more suited to a company with a short mine life, they also don't do cyclones and insist on the horizontal spirals (high wear and power draw) Compared to our cyclones, concentrator set-ups.

      I was there recently looking at gear and also inspected an Operational Chinese gold process plant. It was noted they had 3 times the equipment than we would to treat similar tons, a killer on spare parts and downtime.
      Walter Scholler, Perth, Australia

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    2. Points understood and taken Walter. My comment was as the devils advocate, however it has to be taken seriously. The value of Chinese process plant output must be many times the rest of the worlds' now. This group is only talking about process, though earth moving is also getting attractive. Again something I would NEVER have thought a few years ago. Topic is also talking about the NEXT generation. You are far behind if you don't know the Chinese produce hydrocyclones! They certainly do - not Multotec, and it's best you design/size yourself (or ask Multotec to do it for you!), but they produce and sell. What kind of gold process did you look at? Gravity processes (small to medium scale) are really unbeatable FOR THE COST. Chinese are not yet ready to take on first world large scale projects, but then again, they were not producing electronics 10 years ago, and our Universities are full of Chinese students now. Ignore this trend at your peril!
      Steve Canby

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    3. I guess it was 2012 when I was there, the plant was a gold C.I.L plant in Mongolia, Chinese owned and run. If my memory serves me correct it ran at 50 to 60 tph, for this they had 3 mills numerous conveyors and crushers I think that a lot of what they set up is more suitable to a developing country where you can put an extra 15 to 20 people on a shift at a low cost, when I went to the pump city, pumps looked like Warmans but certainly not the quality, If I were to utilise Chinese gear lets say in Africa, then would get the spares fabricated there (mill liners) similar to Chinese standards without the logistic headache.
      I also found that it was difficult to get any type of operating/maintenance manuals for equipment.
      Walter Scholler

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    4. There is no doubt that CHINA is pulling to the front in producing equipment based on price and delivery time. However, there lingers the question of quality. Will the Chinese be able to provide that. I always remember the discussion of how China bought one Euclid truck, took it apart in China and copied every part in detail and started producing replicas. We do know that they are good at replication, yet again, what is the quality? We must be careful about jumping on the "CHINA Bandwagon" for Mining & Mineral Processing equipment, because we may miss and fall flat on our faces in the near future.
      Louis Bernard, Bernard Mining & Metallurgy, Canada

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    5. I work with and assess suitability of equipment from several Chinese companies. I emphasise, I do not represent or take commission from any. I assure you that most Chinese companies ARE able to produce good quality equipment but they can't for several reasons, mostly because they are forced to cut production costs. Many producers work through Chinese sales agents who take a substantial fee (this is partly political). World wide they are always being driven for a lower price (especially India). To make (sometimes just a meagre) profit, so, quality suffers. It is not that they are UNABLE to produce standard quality.

      But things are changing. One conveyor belt manufacturer I know for example is breaking the mould and starting to sell its own products to foreign retailers and end users, cutting out middle men. The price is still lower than local products, but quality the same. My feeling is that we have to wake up, work with and assist the Chinese, because sooner or later they WILL out price the market. Not 3 years, but 5 or 10? The Chinese will win! Walter is 100% right. For now, we will be mixing and matching Chinese and other nationality equipment, but in future????? It's only a matter of time. If you want scrubbers, log washers, jigs, classifiers, basic flotation cells, etc - nobody outside China can compete. But certain modifications are advised to improve operational characteristics and wear. You will be aware for example, China PRODUCES more gold than any other country. Where do you think they buy the equipment?
      Steve Canby

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    6. I have great experience with Chinese. They copy the equipment and also developed some technologies. I finished a dressing plant project with some specifications (grade, recovery) they got the contract and could not guarantee the results of the tender, however won the contact (they had this ability to get contract with out guarantying the results on the third word). Regarding Jigs they do not have Gekko, which I recommended on the tender, neither a process for recovering very fine minerals ( < 5 microns >10 microns) sunc the Kelsey Jig. The are copying (badly) the Derrick screens, etc. They are good for ball mills, conveyors, classical equipment that is good to buy that has not a influence on the recovery and grade. Also not a good equipment on line assay like Thermofisher. The best experience was a specially equipment that I bought for refining tin , not available on the western countries. In fact I will buy no more than 60% of the equipment from China for a modern dressing plant. The combination is good for the price as some suggestions.
      Jorge Lema Patino, Bolivia

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    7. I have been involved in watching and working for Chinese interests for 20 years and all the above comments are correct when looking at the Chinese manufacturing abilities as a whole. I am convinced that buying from China MUST have first hand inspection of the entire manufacturing process as not all of the Chinese products are "first class". There will be happy customers as well as sad ones that do not do their homework. After dozens of trips to Chinese plants I have found both worlds best practices and on some occasions, less than average products. I have also found leading edge technologies developed 100% locally - no other country spends R&D money like China.
      That time is now.
      (I have no direct interest in Chinese processing equipment). Do the homework with focus on the detail, and get the rewards, is my solid opinion.
      Mark Addison, Sino Grinding (Americas) Inc., USA

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    8. Good advice Mark, totally agree.
      Louis Bernard

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    9. If we look at the humble light bulb, since the cheap Chinese light bulbs are the only available replacements here now, I find we change 20 to 30 a year in the average house which makes it a very expensive alternative to the previous quality bulbs that were available,

      We can't keep going on sacrificing quality for quantity, I'm all for import export and am a firm believer that good quality products will sell themselves, at the right price.

      It would be a shame if in the future low quality products were all that was available at high prices when the competition has been eliminated.
      Walter Scholler

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    10. Walter, you have my vote of agreement. China has a cultural error as they mistake price as the major reason for business. I have seen 70% discounts that are total overkill when 50% would do the job. If that remaining 20% goes into quality. Price as the main mechanism of product selection, in general, is a total fallacy. In many cases we need to advise these new makers how to do it better - to have more suppliers can only be to a buyers advantage.
      Mark Addison

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    11. You get what you pay for. Having also been exposed to Chinese made process equipment, I lament the bean counters who look at the cost only.
      There is more to operating a process plant that fitting it out with cost price equipment. There is never a cost saving in the long run.
      I have worked at too many places that have cut costs and gone for the "Cheap imitation" instead of higher quality product.
      I am not ready yet to accept Chinese product as good or high quality- maybe one day..... I am too sick and tired of trying to rectify a process issue because some piece of cheap plant has broken after a couple of weeks of run time.
      Greg Cox, NSW, Australia

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    12. Greg, I too would not accept any Chinese product without doing a first hand inspection - that producer is going through an industrial renaissance and there are still a few "lumps in the gravy". I also do not like being the guinea pig for new technologies - however, there comes a time when the data is in. References to reconfirm the data is available.
      The promises of bottom line gains are on the table - the gains must be worth the investigation.
      Having done the investigation - decision time comes.
      Do I throw out all my Chinese clothes, automotive parts, electric motors, stationary, toys, fishing rods, which I did NOT investigate before I bought them?
      We actually guarantee our product with a fully risk free trial to all customers.
      With 10 years of first hand data in hand I am totally comfortable.

      Mark Addison, Sino Grinding (Americas) Inc., USA

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  2. The work being undertaken by the AngloGold Ashanti Technology Innovation Consortium is also relevant to this discussion (https://anglogoldashantitechnology.com/).
    John Neale, Mintek, South Africa

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  3. More intense blasting in the mines has been a concept for long. It may be recalled that JKTech had a "mine to mill" slogan quite a while back. It is only that the mines people are quite reluctant to do so as their costs increase and in some cases there are circumstantial difficulties also. Coarse particle separation is also not so novel a concept and a copper slag grinding & beneficiation plant in India had installed it way back in 1970s. However they could not operate it because of various reasons. But this is something worth investigating and stabilizing.

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  4. Dear Sir,
    It's good to see and hear about the new reseach intiatives on energy reduction in mineral beneficiation plants under the head of " next generation concentrator". The emphasis is but natural on effecient grinding, effecient separation (size as well as minerals).
    A similar activity on exsisting tailing pond minerals benefeciation will also benefit.
    Kind regards.
    Venkatesh

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  5. The comments are very informative with lots of hands- on experience, now we are really talking on capital and operating costs
    I have the following questions to ask, to educate myself;
    a) Do we have a graph with the power consumption estimated based on Bond's work index and the actual power being consumed in operating plants; even ten sets of data points would be of interest?
    b) 50 years back, I read and kept on believing that only two percent of input energy is actually useful energy and the rest is lost in heat/sound etc. Is it still the same OR are we doing much better with all the work going on over the years on comminution?
    c) Has the weights(in Kgs) of moving parts in comminution, such as jaw plates/shell of a mill etc come down over the years in view of work in material sciences/new materials etc?
    Rao,T.C., India

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  6. New project of next generation is very fine. Even better that this project made will be JKMRS and Metso Minerals. A place for the project is selected, too fine- Chile. A low bow to the authors of this project.
    So I want to say a little, and if it will help for the authors I will be very happy.
    My investigation time of blasting for ore crushing started in 1991.We reduced the net blasting from 6x6 to 5x5 and blaster consumption increased from 0.6kg to 1.0kg / t. As a result, pieces size decreased from 95mm to 70mm. We determined the energy equation for this process. We got the effect in mining (excavation and transportation of ore) over $6M. In grinding circuit effect we got up to $20M, but can be more if increase the classification capacity.
    Ore sorting we investigated in 2000 ... 2005. We studied two sorting. Sort of small heaps uand sorting pieces of ore. Results unfortunately ambiguous. Sort of heap is successful. Enough to scan the upper layer of the heap. Now there is an plant capacity of 12 million tons per year. Sort by pieces of ore we have failed. The main reason is very low capacity of the separators. Need to develop dry screening without sieve.
    According to the SAG and flotation I will not say anything.
    The overall project is very beautiful.
    I think it would be even better if we consider a small alternative or supplement to the project.
    In Chile, as I know very well developed heap leaching of copper. This process now competes with flotation.
    It is possible alternative flowsheet: conventional blasting and crushing to 50mm - microwave processing ore for liberation copper minerals - heap leaching of copper. We were treated with microwaves ore of size 50 ... 100 mm. The results were good. Here, we can obtain a reduction of water and energy consumption. Is no need to tailings.
    Hvan Alexander, Uzbekistan

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  7. Let me take a different view. Since ore deposits are finite and nonrenewable, I think future lies in zero values in tailings and maximum utilisation of tailings and/or most environmentally friendly operations and disposal.
    If it is so, we need to break particles to nano sizes(may be an inappropriate word),carry out separation of values at those sizes by new processes(preferably in dry state). So our outlook might have to be in the direction of most energy efficient and high capacity comminution and dry separation (if dry is not possible--the most efficient low cost high efficient dewatering new technologies) are the future direction.
    Fine particle processing in new machines and processing of the same by new processes are the areas in which we have to innovate.
    Rao,T.C.

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