Grinding & Classification Circuits

Grinding & Classification Circuits

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Started by
Having used weight control and power draw to control Mill operations, using Mill Sound to run a mill was a new one for me. I found it unusual and not that effective. Has anyone else used that style of operation control to run their mill and did you ...
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Last commented on by niloufar
so in your opinion, with considering a fixed speed SAG mill how can we use smart ear to optimize our grinding process.
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Through continuous improvement and the use of advanced technologies like SmartEar™, Pueblo Viejo are improving the control and operation of their SAG mill, resulting in reduced liner wear, more efficiency.Volume Title: 12th Mill Operators' Conferen...
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Last replied to by niloufar
Hi, we have installed smartear for our SAg mill but till now we could not use it for our grinding optimization and did not find that much correlation between data. if anybody could help us to get more...
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Started by
Has anyone had success with installing load cells for load indication on existing SAG Mills?
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Last commented on by Halbmond
Hi there , Dead link
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Started by Obersturmbann
A few years ago, McGill University in Canada developed a new and more accurate test methodology for predicting steel media consumption. This test (Steel Media Wear Test) is licensed and currently being offered commercially by JKTech. The test also ha...
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Last commented on by MSKabir
Has the papers been published ? Could you kindly provide links to the research papers or source.
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2066
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Started by
Has anyone had any experience with the Outotec MillSense real-time mill charge analyzer? It is a very innovative approach but does it work? Are you using it for day to day decision making?
Last commented on by David
Welcome to 911M Peter
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2264
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Started by Raje Singh
Differences between drives power draw of two drives sag mills. In a double drive/pinion SAG, we face different power draw between each drives. Can this be caused by charge motion or some others process problem?
Last replied to by Maya Rothman
I also think that as the costs for VSD systems decrease, plus that the technology is mature and becoming widely used on large machines, that this is why we are seeing more of them. However, even thoug...
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Started by Paul Morrow
With regards to comparing grinding mills; what are the advantages of vertical milling machine compared to conventional ball mill? A more appropriate term is vertical roller mill or VRM for short.There are two different types of vertical mills: Verti...
Last replied to by Sachin Prakash
Just add small comments to the previous, you will not need classification equipment such as vibrating screen or hydrocyclone for Isa Mill or Verti-Mill circuit. A signature plot test work to determine...
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Started by Victor Bergman
Whether it is practical and/or worthwhile to run a Bond Ball Mill Work Index test at 500 mesh (25 micron)? Are there calculation alternatives? This would be for sizing of fine grinding or regrind mills.
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Last replied to by Obersturmbann
We use grind curves over a range of work inputs using stirred media mills to determine the kWh/t to achieve the desired final particle size distribution. This can be done down to the sub-micron sizes ...
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Started by Rahil Khan
What is your idea about space between SAG mill shell liners? How much space would be appropriate?
Last replied to by
From an installers point of view! Most steel liner suppliers supply rubber widgets or void filling segments to prevent liner movement or creeping to a degree with the initial installation and prevent ...
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Started by
What is the effect of low ball % full on grinding efficiency?One of our clients is thinking of the future and has bought a ball mill that will be the right size someday, but is very large now.I know what happens to mill power from adjustments to % cr...
Last replied to by
Give me actual data of you grinding flowsheet: feed size, product size, power of mill motor, capacity, ball size, numbers & diameter of hydrocyclone ball charge, mill speed. I'm calculate optimum capa...
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Started by Helena Russell
How to estimate the necessary flow rate of air to feed a row of six flotation cells agitators?
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Last replied to by Obersturmbann
Take a look at this article for an approach:Miguel Maldonado, Rodrigo Araya and James FinchAn Overview of Optimizing Strategies for Flotation BanksMinerals 2012, 2, 258-271; doi:10.3390/min2040258http...
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Started by
We are facing a problem at vertical raw mill that mill not getting feed according to designed capacity all things ok. Please share your thinking according to your experience. And one more thing if, in a vertical raw mill operating manual, it is descr...
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Last replied to by Kumar Choudhry
Did you change new liner for table and grinding rollers? Could not get the meaning of all things ok, whether it was running with a designed capacity before?
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Started by Zander Barcalow
A laboratory grindability test made in closed circuit! Should it be regarded as a miniature of a commercial mill operation? Should its performance be scaled-up to the size of a commercial mill?Does the screen analysis of its product and circulating l...
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Last replied to by Obersturmbann
In general, the closed-loop tests are laborious and time consuming. The grinding environment within the ball mill is a first complicating factor for the scale-up. The type of classification used, have...
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Started by
What may be the probable reason of high temperature in slide shoe bearings of cement mill?
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Last replied to by
First thing to do is to check the position of the temperature sensor installed on the slide shoe. Second analyze the high/low pressure oil system. Look for manuals and see working range parameters for...
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Started by Hauptsturm
I am looking for some information about pressure drop in dry SAG mills? How designers calculate the requirement air flow rate for this kind of mills?
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Last replied to by Subhash-Kumar-Roy
Pressure drop is the most important parameter in dry SAG mills because it can make material discharge possible. I depend on mill length and the amount of material in front of the max trunnion opening....
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Started by
Is it true that the lifter release angle of recent installed SAG mills are more than 15 degrees? Will it be the future of lifter geometry and design?
Last replied to by Hauptsturm
Here at MEPSA, we manufacture cast steel liners for OEM's. The latest profiles designs we are working for them, consider SAG's lifters release angles with angles between 20 and 30 degrees
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Started by
Do you know if it’s possible to supply a mill with Squirrel Cage Induction Motor Drive using low tension motors (480V) instead MT? (4160V) when power requirement is less than 1000kw?
Last replied to by Gruppen
Below 1000 kW it is not a big problem to operate the mill with a low voltage motor. The problem is the start-up, where you have 6-7x nominal ampere which is typically not possible for the start-up tim...
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Is there a general rule or a formula to calculate the ideal %ball charge in a SAG mill?
Last replied to by
One important issue: "Work Index is not Hardness", but is the energy we need to reduce from F80 to P80. Also I was reading about the ball recharge policy...for this is very important to know the Abras...
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Started by Amar
What's your suggestion for best recommendation for aP80 of cyclone overflow for lead & zinc to feed a flotation circuit?
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Last replied to by Kumar Choudhry
It is obvious thing that the mineral beneficiation process is to enrich the interested mineral quantity in the concentrate. It directly derives from the optimum liberation of the minerals from the hos...
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Started by Subhash-Kumar-Roy
In a grinding circuit, is there any relationship between SAG mill % solids and P80 (SAG mill product)? And what is the optimum % solid for sag mill?
Last replied to by Sandeep Bisht
Relation between Sag mill solid and product P80!Both are dependent on feed size. Dependent on Volume % solids in SAG mill. Dependent on ball charge volume. Hardness of ore. Recirculation load. De...
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Started by Unterstarm
Do the chemicals of grinding balls have any effect on the final processed product? What's the key chemical element of grinding balls affects the processed final products?
Last replied to by Sandeep Bisht
•High chrome ball wear is less by 50% than hyper steel balls.•Contribution of wear in flotation is negligible. It is the shape of ball till disintegration to zero is the contributing factor. The m...
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Started by Obergruppenfuhrer
As a comparison between Ball mill and Gyratory mill for potash plant, which one is better? (With the aim of reducing fine particles)
Last replied to by Sudhirkumar
Ball mills: They are used for coarser grinding. Mostly wet grinding. Wet process means multiple handling and more cost. Very rarely used for dry grinding. Cement, pellet feed. etc.Gyratory: It is used...
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Started by Rahil Khan
Does anyone know about determining the breakage function of SAG Mill using JKMRC method and determining the b(i,j) for all sizes.
Last replied to by Maya Rothman
If you want to determine your breakage and selection function for any current operation you can use our Moly-Cop Tools SAG Model, we have an Excel routine to get your parameters, then you can use this...
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Started by
Apart from Bond's EF factors (CA Rowland), what other scale-up factors are applied to lab BWI for large-scale ball mill sizing?
Last replied to by Maya Rothman
The EF factors are usually sufficient to size a large ball mill. There used to be a discussion in the industry about whether they were suitable above, if I remember correctly, 18 ft diameter. That dis...
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Started by Oberstorm
A laboratory grindability test made in closed circuit. Should it be regarded as a miniature of a commercial mill operation? Should its performance be scaled- up to the size of a commercial mill?Does the screen analysis of its product and circulating ...
Last replied to by
Closed circuit milling at small scale (Bond mill sizes) provides opportunities to simulate mineral deportment issues, which you can't do in a basic batch mill except by doing locked cycle test, which ...
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Started by Maya Rothman
Last commented on by David
Example signature plot https://www.911metallurgist.com/blog/ultrafine-grinding-test-report-isamill-signature-plot
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Started by
Is the JK rock hardness method specifically A*b patented?Actually I want to know if I am able to define it myself and report it in a paper or not.
Last replied to by
From a legal perspective, the JK Drop Weight machine, test and the associated results analysis to generate A and b parameters are not patent protected so there is nothing to stop you doing your own te...
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Started by Victor Bergman
How can a trommel be effectively used?
Last replied to by
The trommel screen is like a micron screen, it remove large objects (oversize, bushes, plants, rocks) from feed from the mine to avoid choked feed pipes and or plant instability, and the (undersize/mi...
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Started by
For secondary grinding (Ball Mill), what discharge Configuration is ideal with regards to cost saving for atypical copper milling plant with a throughput of say 331dmt/h. Qualify the selection of your recommendation.
Last replied to by
The SAG mill is in open circuit. The only classification is by a double deck vibro screen with screen aperture of 10X10mm on top deck and 6X6mm on the bottom deck.
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Started by
We recently converted a grate discharge type ball mill (size 5.7X8.6m) to an Overflow type. Before conversion, the ball level was 26%, and we were able to obtain a grind of 90%+ passing 75mic at a throughput of 350t/h. After conversion it’s a night...
Last commented on by David
Thanks for this Johan
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Started by Standartenfurer
I’m looking for ideas to process the discarded material of a SAG mill. We have huge material stocks of this process that contains ore contaminated with metal balls and some scrap elements that makes it hard to process it on a crusher. I have seen a...
Last replied to by
You may find more information regarding the SAG discharge if you search them as "scats" (broken ball chips). Safety Notes; they result from internal stresses in the balls impact and heat energy in the...
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Started by
How to stop the leakage through seal ring and seal wiper in wet ball mill?
Last replied to by
Yes the mill is almost running with double its capacity (Rated 30TPH, running with 55 TPH), earlier we used to have Linatex seal wiper and SS seal ring. In this course Linatex seal wiper didn't give g...
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Started by Jean Rasczak
Auditing can be a key for continues improvement of mineral processing circuits specially grinding/comminution but every experts have their own way which might be achieved over the year by experience. It'll be perfect if everyone can make profit of t...
Last replied to by
I was recently informed by one of my friend about a new book about auditing a mineral processing plant. I hope to study it on google book.http://smemi.personifycloud.com/PersonifyEbusiness/Store/Produ...
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Started by
Interesting article link below, it gives a new approach on how to measure assets productivity. I think is more "real" than OEE. For commutation normally I would use a logic where OEE = (availability or run-time) * (Avg TPD/max TPD) * (recovery %). Th...
Last replied to by Jean Rasczak
Wrong metrics in my view. This thinking leads us along the mindless treadmill of more volumes and higher utilizations which are guaranteed to maximize (total) costs, even though they create an illusio...
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Started by
As a grinding media designer/supplier SGI considers that an MBT is not the best method for media selection.Do marked ball tests help determine if you have selected the best media for you mill?
Last replied to by
Yes, so much effort and expense to do this work - the cheap and easy part is the final data analysis. See page 101 of https://books.google.ca/books?id=sFhUPTaREnsC&lpg=PA103&ots=XC4BoEG8K2&dq=Marked...

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