tag:blogger.com,1999:blog-6908362959739425575.post2037595213591233816..comments2024-03-26T21:47:45.016+00:00Comments on MEI's Barry Wills: Comminution: developments and thoughts over the last decadeMEIhttp://www.blogger.com/profile/14834780351452765156noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-6908362959739425575.post-58345708577431782712020-06-05T13:34:02.631+01:002020-06-05T13:34:02.631+01:00Dr.Wills, thank you very much. This is a useful re...Dr.Wills, thank you very much. This is a useful review. I hope that we can see this review on a future paper. I would like to raise some additional points:<br /><br />1. There seems to be two distinct sets of studies: (i) The studies focusing on particle breakage phenomena, (ii) the studies focusing on empirical or semi-empirical models of size-reduction processes. They are rarely connected with each other. For understanding size-reduction processes and developing permanent models, these two groups must be evaluated together. I feel that the only fundamental information that we currently have on size-reduction operations is still the grinding laws. However, fragmentation patterns and impact mechanics are widely studied in applied physics, astronomy, etc. These studies may provide insight on the fundamentals of size-reduction processes.<br /><br />2. There are some evidence regarding the positive effects of ultrasonic cavitation on grain-boundary cracking of materials in water. Could we perhaps use this cavitation technique to a flowing slurry as a pretreatment or direct breakage method ?<br /><br />3. Laser spalling is acknowledged in petroleum science to fracture rocks for (i) oil production, marble cutting (ii) and (iii) concrete waste spalling. It requires very short processing times and small energy inputs. Could we arrange lasers for pretreatment or breakage of rocks during gravitational flow of dry ore streams ?<br /><br />RegardsMahmut Camalannoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-2154022812589820902020-05-27T09:34:57.079+01:002020-05-27T09:34:57.079+01:00Thanks John, and yes, very much aware of that. Loe...Thanks John, and yes, very much aware of that. Loesche has been a major contributor to MEI's comminution conferences, and was a sponsor of the last two ('16 and '18).MEIhttps://www.blogger.com/profile/14834780351452765156noreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-77885467451225545732020-05-27T06:35:05.253+01:002020-05-27T06:35:05.253+01:00Thanks for a great summary Barry.
Do you know that...Thanks for a great summary Barry.<br />Do you know that Loesche is interested in marketing their technology in the Minerals space?<br />Regards,<br />John Johnhttp://www.johenconsulting.comnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-88369206757427367642020-05-26T01:00:47.034+01:002020-05-26T01:00:47.034+01:00I agree Jason. I see pre-concentration as a way t...I agree Jason. I see pre-concentration as a way that existing operations can look to reduce their comminution energy requirements without significantly changing their circuits or equipment. While not every site will be able to benefit from pre-concentration, I am convinced that many can. Also, tangible downstream processing benefits to be had as well. <br /><br />Michael Myllynen, Magotteaux.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-77197264079613064742020-05-22T16:32:54.517+01:002020-05-22T16:32:54.517+01:00Great roundup Barry! Very interesting
Carly Leoni...Great roundup Barry! Very interesting <br />Carly Leonida, UK<br />Freelance technical writer and editor, owner/author of The Intelligent Miner, European editor at Mining Media IntlAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-71299106086554357472020-05-21T19:39:02.419+01:002020-05-21T19:39:02.419+01:00SAG mills were adopted to solve a particular set o...SAG mills were adopted to solve a particular set of problems in the Industry, so it is probably reasonable to ask if those problems remain relevant in the present and future -- and whether or not alternative technologies will rediscover the problems that are long since solved.<br /><br /> Example problems:<br /> - dry processes like crushing & screening make a lot of dust; wet milling is preferred for industrial hygiene.<br /> - simpler flowsheets, a lot of crushers & conveyors were replaced with a single SAG mill -- but then the industry started adding crushers and conveyors around and before SAG mills, so do we still have simpler flowsheets?<br /> - SAG mills require less labour and were easier to automate than crushing plants. Show me a conveyor that doesn't spill and I'll show you a conveyor that isn't running.<br /> - Cold weather climates benefit from an indoor SAG mill; no need for fine ore bins which have a nasty habit of freezing into ice-pops in -30°C temperatures. As my Peruvian taxi driver once commented: "what do you mean, minus temperature? How is that even possible?"<br /> - Capital costs tended to be lower for SAG circuits, at the expense of higher power & consumables operating costs. Give an MBA the option of saving CAPEX or OPEX and I'm sure you can guess the answer.<br /> - Tumbling mills were easier to scale up than competing technologies in the 1970s/1980s. The 21st century hasn't resulted in bigger rod mills, but it certainly has given us bigger crushers and large alternative (stirred) mills. <br /><br /> Final thought: I think it is fair to say that the industry knows how to size SAG mill and ball mill circuits -- even though as Paul Staples said, you can still screw it up if you try hard enough. There is value in a McNulty Type 1 curve associated with boring, reliable, and old- fashioned tumbling mill technology.<br /><br />Alex Doll, Alex G Doll Consulting Ltd., Canada<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-60693030100757074382020-05-20T13:37:46.415+01:002020-05-20T13:37:46.415+01:00Thanks, we are keeping well. I look forward to yo...Thanks, we are keeping well. I look forward to your next post.<br />TedAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-14454365513511655102020-05-19T13:32:30.045+01:002020-05-19T13:32:30.045+01:00Good summary Barry,
I will add to the summary:
- ...Good summary Barry,<br /><br />I will add to the summary:<br />- Testwork: The past decade has seen a growing number of projects valuing the benefit of conducting proper variability ore characterization testwork and Geometallurgy approach in the design of comminution circuit. The cost of variability/Geometallurgy testwork is matching the cost of pilot testwork as known in the past using 30 t of ore.<br />Subsequently, there has been development of simplified testwork for standard tests such the Bond Ball Work Index to reduce the sample requirement, cost and duration per test. <br />- Influence of "External" factors: The Mine to Mill concept, Pre-concentration (ore sorting, Dense Media separation, mag sep), "Grade engineering" and Coarser flotation have influenced probably more this decade than the previous, the design of comminution circuits.<br />- Equipment size: While this decade has seen the growing in size of many equipment ( Metso 3 m HPGR, MP2500 cone crusher,... ), the size of the SAG/AG mill did not increase significantly <br />- Circuit trends: Single Stage SAG mill and pre-crushing before the SAG mill topics have been studied extensively in addition to HPGR (tradeoff SAG vs HPGR), Fine milling. <br />- Control of comminution circuit and equipment: Many improvements overall + the addition of new ones such as the MillSlicer <br /><br />Regards,<br /><br />Johnny T. KalalaAnonymoushttps://www.blogger.com/profile/09018963381396059109noreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-21454023559442108512020-05-19T10:30:59.460+01:002020-05-19T10:30:59.460+01:00Barry,
I appreciate such summaries, periodically,...Barry,<br /> I appreciate such summaries, periodically, so that people do not reinvent the wheel.<br />I have some thoughts . comments as a holistic perspective<br /><br />a) I firmly believe that "comminution" should never be looked in<br />isolation--blasting and subsequent beneficiation should be in focus<br />while talking on crushing/grinding machines.<br />2)I still believe discussions on which machines to be used for<br />comminution will remain a discussion point unless we have more data on<br />the material(ore characteristics-including whether the ore is<br />friable/W.I./ hardness/grain size distribution i.e. more PhDs on the<br />relation between ore characteristics and breakage relationship is well established.<br />d)Screens or cyclones are not a big issue. I go to screens only when<br />it gets established that all values would be in either screen oversize or<br />undersize. I am sure we will never have such clear phenomena; we will<br />always have gangue in products from a screen.<br />Screens have limited design/operating variables to easily and quickly<br />change,.If tonnage to plant or ore characteristics change, while in<br />cyclones one can shut off a few cyclones in a battery/ can change flow<br />rate/spigot diameter and so on.<br />ONLY A HOLISTIC UNDERSTANDING AND CLEAR KNOWLEDGE OF EACH UNIT<br />OPERATION should be the starting point.<br /><br /><br /><br />Rao,T.C.https://www.blogger.com/profile/11160713677908165404noreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-76117570142033648382020-05-19T09:22:22.099+01:002020-05-19T09:22:22.099+01:00Hi Ted. All well here thanks, and I hope you and C...Hi Ted. All well here thanks, and I hope you and Claire are coping with the crisis. Thanks for mentioning preconcentration (and you too Jason). This is something I want to include in a future review article on physical separation methodsMEIhttps://www.blogger.com/profile/14834780351452765156noreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-73712412337530263532020-05-19T09:17:12.881+01:002020-05-19T09:17:12.881+01:00Nice round-up and I hope you are all keeping well....Nice round-up and I hope you are all keeping well. You referred to the 2012 conference and I also remember talking you about the need for comminution to change, so that it is not simply about blanket size reduction. Rather we need the amount of comminution that is suited to the required purpose, i.e. if you want to implement coarse size based preconcentration (and the ore is amenable), how do you ensure the comminution generates a size distribution that will maximize the value from the sorting. <br />Ted Bearman, Bear Rock Solutions Pty. Ltd., AustraliaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-66758232935897388852020-05-19T09:15:08.771+01:002020-05-19T09:15:08.771+01:00No doubt that replacing classifying cyclones with ...No doubt that replacing classifying cyclones with screens has been one of the important developments in comminution efficiency and flotation performance with ball mills and hopefully will become easier to sell soon.<br />Roger Strickland, Tablelands Mining Group, AustraliaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-76457047346848799582020-05-19T02:21:17.273+01:002020-05-19T02:21:17.273+01:00It's also important to consider pre-concentrat...It's also important to consider pre-concentration technologies to reduce the volume of material that requires grinding and the implications of finer grinding for tailings dewatering and storage. <br /><br />Jason Maguire, University of Queensland Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-9375582895900649142020-05-18T23:50:13.614+01:002020-05-18T23:50:13.614+01:00Very eloquent elaboration of the comminution devel...Very eloquent elaboration of the comminution developments in the last decade, the discussion on the efficiency of the screen circuit over the hydrocyclones is indeed one that needs further discussion in terms of data collection from operating plants that have replaced either one of the operating units. The other notable mention of the Ultrafine grindinding mills involving ceramic grinding media is one that is worth pursuing. I was personally involved in the installation and commissioning of the two units in one of the platinum mines in RSA and the initial results were very positive. steady Khttps://www.blogger.com/profile/08819980464658999156noreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-56591430318765510992020-05-18T15:56:11.121+01:002020-05-18T15:56:11.121+01:00Really good Barry, please keep us informed!
Marco ...Really good Barry, please keep us informed!<br />Marco Vera, Manager Recovery Innovation Process Technologies, AustraliaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-10456464615243356422020-05-18T15:54:03.868+01:002020-05-18T15:54:03.868+01:00A great summary of the evolution in comminution pr...A great summary of the evolution in comminution process...<br />Daniel Jordán, Process Superintendent LBUG Project, ChileAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-92230811456230057102020-05-18T15:52:23.999+01:002020-05-18T15:52:23.999+01:00A great insight into evolution and development of ...A great insight into evolution and development of Comminution with respect to change in Ore characteristics.<br />Jyotirmaya Sahoo, Arcelor Mittal Nippon Steel India LtdAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6908362959739425575.post-6991142759847515572020-05-18T13:38:43.026+01:002020-05-18T13:38:43.026+01:00Nice summary of the last years, Barry, thanks!
Dan...Nice summary of the last years, Barry, thanks!<br />Daniel Parvaz, Lightning Machines Science and Communication, UKAnonymousnoreply@blogger.com