- To participate in the 911Metallurgist Forums, be sure to JOIN & LOGIN
- Use Add New Topic to ask a New Question/Discussion about Grinding.
- OR Select a Topic that Interests you.
- Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
Using Add Reply allows you to Attach Images or PDF files and provide a more complete input. - Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.
3
REPLIES
6569
VIEWS
Started by pitachikondi
A ball mill is operated in closed circuit with sieve bend under steady state conditions as shown in the attached diagram.The % solids in each stream are indicated.The water addition to the sump is 100 cubic metres per hr and to the mill feed is 67...
A ball mill is operated in closed circuit with sieve bend under steady state conditions as shown in the attached diagram.The % solids in each stream are indicated.The water addition to the sump is 100 cubic metres per hr and to the mill feed is 67...
26
REPLIES
4730
VIEWS
Started by Sandeep Bisht
What are the reasons and solution for liner breakage? Tell us about effect of changing liner geometry, adding some feature to liners, type of material and metallurgical operation of liners on deceasing break.It may happen for both of them but since n...
What are the reasons and solution for liner breakage? Tell us about effect of changing liner geometry, adding some feature to liners, type of material and metallurgical operation of liners on deceasing break.It may happen for both of them but since n...
Last replied to by Victor Bergman
Yes, correct. We have 2 different HPGR's, one for cement applications and the other one for minerals. The main differences are the wear protection (minerals: tungsten carbide studs) and hydraulic pres...
Yes, correct. We have 2 different HPGR's, one for cement applications and the other one for minerals. The main differences are the wear protection (minerals: tungsten carbide studs) and hydraulic pres...
17
REPLIES
2331
VIEWS
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 ...
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 ...
5
REPLIES
2205
VIEWS
Started by Oberfuhrer
What formulation should I use for the estimated calculation of rubber type mill liners wear rate?
What formulation should I use for the estimated calculation of rubber type mill liners wear rate?
Last replied to by David
what do you mean by models? for manufacturer contact glarose@bradken.com + he can guide you on design/shapes. for general steel ball mill designs and profiles see https://www.911metallurgist.com/blog...
what do you mean by models? for manufacturer contact glarose@bradken.com + he can guide you on design/shapes. for general steel ball mill designs and profiles see https://www.911metallurgist.com/blog...
3
REPLIES
5268
VIEWS
Started by marwa phanuel mwita
fail to regulate pressure of cyclone feed may result to the proble in recovery, so what are these impact for too high or too low pressure?
fail to regulate pressure of cyclone feed may result to the proble in recovery, so what are these impact for too high or too low pressure?
3
REPLIES
1701
VIEWS
Started by sandlady
Hi all, I am looking at purchasing a new ball mill for a slice sand operations. We are looking to grind down a 170/270 whole grain silica to a 325 Mesh (-200). I'm beginning this search and would like any opinions on what size of ball mill to explor...
Hi all, I am looking at purchasing a new ball mill for a slice sand operations. We are looking to grind down a 170/270 whole grain silica to a 325 Mesh (-200). I'm beginning this search and would like any opinions on what size of ball mill to explor...
Last replied to by Maya Rothman
Oh, here is what you need: https://www.911metallurgist.com/blog/how-to-size-a-ball-mill-design-calculator-formula https://www.911metallurgist.com/blog/grinding-mills https://www.911metallurgist.com...
Oh, here is what you need: https://www.911metallurgist.com/blog/how-to-size-a-ball-mill-design-calculator-formula https://www.911metallurgist.com/blog/grinding-mills https://www.911metallurgist.com...
6
REPLIES
5700
VIEWS
Started by JB
One of our Ball Mills keeps losing pressure on the high pressure pump. It will run fine when starting the Mill and suddenly after a while sometimes 1hrs the pumps will loose pressure. We have just grinded the journal and installed new white metal bea...
One of our Ball Mills keeps losing pressure on the high pressure pump. It will run fine when starting the Mill and suddenly after a while sometimes 1hrs the pumps will loose pressure. We have just grinded the journal and installed new white metal bea...
5
REPLIES
7146
VIEWS
Started by maxwell
My company using ball mill as the second stage of grinding usually experiences high mill mass. we are therefore forced to grind out in order to reduce the mill mass. We also experience excessive overflow of materials/feed entering the ball mill fr...
My company using ball mill as the second stage of grinding usually experiences high mill mass. we are therefore forced to grind out in order to reduce the mill mass. We also experience excessive overflow of materials/feed entering the ball mill fr...
Last replied to by Craig Lockhart
Hello Maxwell, I have experienced the mill overload issue at numerous operations, and most often I find the transfer size from the primary grinding circuit is the culprit and may require re-configura...
Hello Maxwell, I have experienced the mill overload issue at numerous operations, and most often I find the transfer size from the primary grinding circuit is the culprit and may require re-configura...
1
REPLY
1870
VIEWS
Started by Question Emailed
Typically we work with Bond Ai for specifying our equipment into the mining industry. The relationship between Bond Ai and Bond Work index as I understand is the higher the number on the Bind Work Index the more abrasive the material is. Can you plea...
Typically we work with Bond Ai for specifying our equipment into the mining industry. The relationship between Bond Ai and Bond Work index as I understand is the higher the number on the Bind Work Index the more abrasive the material is. Can you plea...
Last replied to by David
Hi,see https://www.911metallurgist.com/blog/rod-ball-impact-crushing-abrasion-the-bond-work-index-family and https://www.911metallurgist.com/blog/bond-abrasion-index-vs-bond-work-index
Hi,see https://www.911metallurgist.com/blog/rod-ball-impact-crushing-abrasion-the-bond-work-index-family and https://www.911metallurgist.com/blog/bond-abrasion-index-vs-bond-work-index
13
REPLIES
4282
VIEWS
Started by Victor Bergman
SAG Mill Process Control - What do you prefer? Controlling Weight (within a range) by manipulating mill speed and keeping a constant feed rate? Controlling weight by manipulating feed rate?
SAG Mill Process Control - What do you prefer? Controlling Weight (within a range) by manipulating mill speed and keeping a constant feed rate? Controlling weight by manipulating feed rate?
Last commented on by Lymon chibona
There are maybe other factors that can be used to control the Sag but the feed size has a significant effect on its throughput the aim is running at a high throughput at a low power draw larger feed s...
There are maybe other factors that can be used to control the Sag but the feed size has a significant effect on its throughput the aim is running at a high throughput at a low power draw larger feed s...
1
REPLY
1779
VIEWS
Started by Paul Morrow
Based on the data I collected from the client, we have the total power, P80, and F80 for the grinding circuit but not the values for the various circuit components (crusher, ball mill, rod mill and tertiary mill).Would it be correct to apply the bond...
Based on the data I collected from the client, we have the total power, P80, and F80 for the grinding circuit but not the values for the various circuit components (crusher, ball mill, rod mill and tertiary mill).Would it be correct to apply the bond...
Last replied to by David
Hi,I conferred with my friend at SAGMilling.com and he says the short answer is yes. The SMC test is one way that you can "benchmark" an operating mill against a theoretical power consumption for a "t...
Hi,I conferred with my friend at SAGMilling.com and he says the short answer is yes. The SMC test is one way that you can "benchmark" an operating mill against a theoretical power consumption for a "t...
1
REPLY
1518
VIEWS
Started by
In a Ball Mill Motor Bearing, where does Lead (Pb) come from as shown in the oil analysis data and what does it indicate?
In a Ball Mill Motor Bearing, where does Lead (Pb) come from as shown in the oil analysis data and what does it indicate?
Last replied to by David
Lead can be present in the bearing material( composition of bearing) thus if you suffer some touchdowns or the bearing is not fully floating on oil you will get traces in the sample. Look for scuff ma...
Lead can be present in the bearing material( composition of bearing) thus if you suffer some touchdowns or the bearing is not fully floating on oil you will get traces in the sample. Look for scuff ma...
2
REPLIES
3815
VIEWS
Started by shamita.1208
I need to understand how do I use the selection, breakage and appearance function equations in predicting the particle size distribution in the mill discharge given the ore characteristics and mill feed particle size distribution? I need to understan...
I need to understand how do I use the selection, breakage and appearance function equations in predicting the particle size distribution in the mill discharge given the ore characteristics and mill feed particle size distribution? I need to understan...
Last replied to by David
A friend familiar (SAGMilling.com) with breakage and appearance function equations tells me you need to take either a JK SimMet course or a Molycop Tools course to be able to do that. The models are...
A friend familiar (SAGMilling.com) with breakage and appearance function equations tells me you need to take either a JK SimMet course or a Molycop Tools course to be able to do that. The models are...
13
REPLIES
2240
VIEWS
Started by Helena Russell
We are looking at the best practice to take the moisture sample of SAG Feed. The alternatives are on the belt conveyor or at the stockpile. Does anyone have any experience with this sampling practice? Which one will be more practicable and more repre...
We are looking at the best practice to take the moisture sample of SAG Feed. The alternatives are on the belt conveyor or at the stockpile. Does anyone have any experience with this sampling practice? Which one will be more practicable and more repre...
Last commented on by Craig Lockhart
Once you have established a moisture database through multiple belt samples, you should nominate a moisture content that you are confident will not overstate your throughput and just stick with it, or...
Once you have established a moisture database through multiple belt samples, you should nominate a moisture content that you are confident will not overstate your throughput and just stick with it, or...
2
REPLIES
3953
VIEWS
Started by Nickbob
I would like to know the effect of ball mill cyclone overflow density on P80 of 150um. I ask this because at either higher or lower densities, you can get your P80 @ 150um (at least 80% passing 150um). Kindly advise on what densities would you g...
I would like to know the effect of ball mill cyclone overflow density on P80 of 150um. I ask this because at either higher or lower densities, you can get your P80 @ 150um (at least 80% passing 150um). Kindly advise on what densities would you g...
Last commented on by Craig Lockhart
Gents, Sounds to me like the cyclones are not optimized - what size/brand cyclones are you operating? How many? Inlet pressure target? Orifice sizes? Sounds like you could get a lot more efficient on ...
Gents, Sounds to me like the cyclones are not optimized - what size/brand cyclones are you operating? How many? Inlet pressure target? Orifice sizes? Sounds like you could get a lot more efficient on ...
10
REPLIES
3009
VIEWS
Started by Nickbob
In a chalcopyrite concentrator, what is the best flotation feed, grind size that you can do in order to optimise flotation operations? Maybe as in size distribution?
In a chalcopyrite concentrator, what is the best flotation feed, grind size that you can do in order to optimise flotation operations? Maybe as in size distribution?
Last commented on by Craig Lockhart
Hello Gents, In my experience, I have found that it is not uncommon to employ primary grinds beyond industry norms when treating high-grade copper ores - the incremental additional recovery that can b...
Hello Gents, In my experience, I have found that it is not uncommon to employ primary grinds beyond industry norms when treating high-grade copper ores - the incremental additional recovery that can b...
3
REPLIES
3247
VIEWS
Started by karthikttl
Hello. I am working in a sand washing plant In India. We are using hydrocyclones to separate sand & clay. But these hydrocyclones are not performing well. We are using Stubby hydrocyclones so more amount of sand is sending to the overflow.We have in...
Hello. I am working in a sand washing plant In India. We are using hydrocyclones to separate sand & clay. But these hydrocyclones are not performing well. We are using Stubby hydrocyclones so more amount of sand is sending to the overflow.We have in...
Last replied to by David
I just noted your Overflow pipes are directly connected to the take-away pipe. This risk to create a syphon from the inner cyclone content directly to the O/F. Look at the imaginary green pipe ...
I just noted your Overflow pipes are directly connected to the take-away pipe. This risk to create a syphon from the inner cyclone content directly to the O/F. Look at the imaginary green pipe ...
15
REPLIES
3186
VIEWS
Started by Sandeep Bisht
What should be the rock and ore feed size for rod mill? What product P80 size should I feed the rod mill?
What should be the rock and ore feed size for rod mill? What product P80 size should I feed the rod mill?
Last replied to by Unterstarm
19-25mm
19-25mm
11
REPLIES
1845
VIEWS
Started by
A lining redesign (shell lifters, grate plates and pulp lifters) done at the Cortez Gold Mines (Crescent Valley, Nevada) SAG mill has produced a very definite reduction in power draft; it is estimated that the power decreases in the 230-370 kW range....
A lining redesign (shell lifters, grate plates and pulp lifters) done at the Cortez Gold Mines (Crescent Valley, Nevada) SAG mill has produced a very definite reduction in power draft; it is estimated that the power decreases in the 230-370 kW range....
Last replied to by Obersturmbann
We have evaluated more than 50 AG/SAG mills from different plants around the world, and their PI or equivalent databases. We simulated the operating parameters and were able to match the same power, s...
We have evaluated more than 50 AG/SAG mills from different plants around the world, and their PI or equivalent databases. We simulated the operating parameters and were able to match the same power, s...
9
REPLIES
7247
VIEWS
Started by Sandeep Bisht
What is difference between Trunnion Bearing & slide shoe bearing in respect of cost, maintenance, reliability?From what I understand, slide shoe bearings are cheaper for smaller and medium sized mills. So why does the industry in general only offer m...
What is difference between Trunnion Bearing & slide shoe bearing in respect of cost, maintenance, reliability?From what I understand, slide shoe bearings are cheaper for smaller and medium sized mills. So why does the industry in general only offer m...
Last replied to by Oberfuhrer
Just a comment re applications of slipper pad / slide shoe bearings - yes, they were originally created for use in cement mills, however have been successfully used in all mineral applications as well...
Just a comment re applications of slipper pad / slide shoe bearings - yes, they were originally created for use in cement mills, however have been successfully used in all mineral applications as well...
10
REPLIES
1989
VIEWS
Started by
Most SAG grinding operations currently use ball size between 5.5 and 6 inch maximum size, However, in most cases the use of these ball sizes hasn't been justify.
Most SAG grinding operations currently use ball size between 5.5 and 6 inch maximum size, However, in most cases the use of these ball sizes hasn't been justify.
Last replied to by Amar
Great comments! Recently I’d been focusing on balls (It’s not kind of balls that you are thinking about 🙂 ). Well in SAG mills because of high impact energies, specific hardness is needed. What ...
Great comments! Recently I’d been focusing on balls (It’s not kind of balls that you are thinking about 🙂 ). Well in SAG mills because of high impact energies, specific hardness is needed. What ...
5
REPLIES
1922
VIEWS
Started by
What is the best Practices to eliminate flow-back and carryover of slurry and solids in a SAG/AG Mill? Are curved Pulp Lifters as Vortex (Bradken) and Turbo Pulp Lifter (Outotec) the best way to approach this issue? Are you aware of any similar produ...
What is the best Practices to eliminate flow-back and carryover of slurry and solids in a SAG/AG Mill? Are curved Pulp Lifters as Vortex (Bradken) and Turbo Pulp Lifter (Outotec) the best way to approach this issue? Are you aware of any similar produ...
Last replied to by Standartenfurer
From a mechanical point of view, curved pulp lifters increase the number and layout of liner bolt holes in the end wall for the mill. In addition, as the curve is either LH or RH, it can "lock" the op...
From a mechanical point of view, curved pulp lifters increase the number and layout of liner bolt holes in the end wall for the mill. In addition, as the curve is either LH or RH, it can "lock" the op...
7
REPLIES
2698
VIEWS
Started by Subhash-Kumar-Roy
Is there any generic parameter for over grinding? Such as percent of fines, etc.
Is there any generic parameter for over grinding? Such as percent of fines, etc.
Last replied to by
To change the grinding conditions is a good way. Some phosphate plant use grinding rods to avoid over grinding.
To change the grinding conditions is a good way. Some phosphate plant use grinding rods to avoid over grinding.
7
REPLIES
6092
VIEWS
Started by Helena Russell
Does anyone have a chart to know if there is any relation between the feed size and the size of the ball needed to grind the ore in SAG and Ball mills?
Does anyone have a chart to know if there is any relation between the feed size and the size of the ball needed to grind the ore in SAG and Ball mills?
Last replied to by Unterstarm
Good to watch for potential build-up of oversize particles when initially running your circuit. There's nothing quite like starting to throw lots of oversize material into flotation.Good to know the v...
Good to watch for potential build-up of oversize particles when initially running your circuit. There's nothing quite like starting to throw lots of oversize material into flotation.Good to know the v...
7
REPLIES
2551
VIEWS
Started by Sudhirkumar
What’s the effect of running the SAG Mill at a speed less the 75% of the critical?
What’s the effect of running the SAG Mill at a speed less the 75% of the critical?
Last replied to by Rahil Khan
If you have to reduce the SAG mill speed because of avoiding liner breakage, maybe it’s better to modify the shell lifter design. Low speed may cause decreasing capacity, higher steel ball and liner...
If you have to reduce the SAG mill speed because of avoiding liner breakage, maybe it’s better to modify the shell lifter design. Low speed may cause decreasing capacity, higher steel ball and liner...
11
REPLIES
2027
VIEWS
Started by
What are the chances to get peening in liners after a grind-out? Is it common to see the whole mill liners under these conditions when a grind-out occurs or is it correct to deduce these ball-hitting marks come from operational conditions?
What are the chances to get peening in liners after a grind-out? Is it common to see the whole mill liners under these conditions when a grind-out occurs or is it correct to deduce these ball-hitting marks come from operational conditions?
Last replied to by
As with everything, we continually learn how to improve such procedures such as these - listed below are our current and well considered steps with explanations of why each step is made.[In priori...
As with everything, we continually learn how to improve such procedures such as these - listed below are our current and well considered steps with explanations of why each step is made.[In priori...
17
REPLIES
3077
VIEWS
Started by Raje Singh
Anyone has experience in relating the Bond Abrasion index to liner consumption
Anyone has experience in relating the Bond Abrasion index to liner consumption
Last replied to by Obergruppenfuhrer
See the paper by Carlos & Levi is very handy. "Measuring, Predicting and Managing Grinding Media Wear" by A.Giblett and J.Seidel 2011 also contains some very good data.http://is.gd/KK4H6E
See the paper by Carlos & Levi is very handy. "Measuring, Predicting and Managing Grinding Media Wear" by A.Giblett and J.Seidel 2011 also contains some very good data.http://is.gd/KK4H6E
11
REPLIES
1686
VIEWS
Started by Sachin Prakash
Who knows what is the best machine or grinding mill for size reduction when the feed size is 3 -8mm and we want product size be( 200 -900)micron and -200 micron be minimum% because 0-200 micron is reject sizethe material is calcium carbonate
Who knows what is the best machine or grinding mill for size reduction when the feed size is 3 -8mm and we want product size be( 200 -900)micron and -200 micron be minimum% because 0-200 micron is reject sizethe material is calcium carbonate
Last replied to by
Recently we have made some tests to produce a granulated material which contains no more too fine sandy, to thereby employ a hammer mill feed 15-18 t/h, F50= 3.5 mm and D50 = 0.6 mm. The Raymond mill ...
Recently we have made some tests to produce a granulated material which contains no more too fine sandy, to thereby employ a hammer mill feed 15-18 t/h, F50= 3.5 mm and D50 = 0.6 mm. The Raymond mill ...
6
REPLIES
1979
VIEWS
Started by Sudhirkumar
Is the grate discharge arrangement ideal for the secondary (ball) mill?
Is the grate discharge arrangement ideal for the secondary (ball) mill?
Last replied to by Rahil Khan
In simple words, grate discharge mills give higher tonnage, but produce coarser grinding, that may cause problem in your Flotation recovery, Grate discharge will also reduce your EGL. The best option ...
In simple words, grate discharge mills give higher tonnage, but produce coarser grinding, that may cause problem in your Flotation recovery, Grate discharge will also reduce your EGL. The best option ...
12
REPLIES
3655
VIEWS
Started by Gruppen
We are looking at a 1 MTPA comminution circuit that goes from a tertiary crush to a single ball mill (closed on a cyclone cluster) to produce a 100 µm P80 product. We're doing a trade-off study. Closing the tertiary on the screen or leaving it open!...
We are looking at a 1 MTPA comminution circuit that goes from a tertiary crush to a single ball mill (closed on a cyclone cluster) to produce a 100 µm P80 product. We're doing a trade-off study. Closing the tertiary on the screen or leaving it open!...
Last replied to by Gruppen
By the way this project has been stalled due to tenure issues but the challenge (minimum cost of getting into production, even symbolically) is still worthy of consideration. The design can allow for ...
By the way this project has been stalled due to tenure issues but the challenge (minimum cost of getting into production, even symbolically) is still worthy of consideration. The design can allow for ...
6
REPLIES
1983
VIEWS
Started by Subhash-Kumar-Roy
Does the phenomenon of mill liner packing also happen in dry SAG mills? In both Shell and head lifters?
Does the phenomenon of mill liner packing also happen in dry SAG mills? In both Shell and head lifters?
Last replied to by Subhash-Kumar-Roy
In dry SAG mills the head lifters play important role. The ground materials should be distributed on suction area. Part of this job should be done by head lifters.
In dry SAG mills the head lifters play important role. The ground materials should be distributed on suction area. Part of this job should be done by head lifters.
3
REPLIES
1724
VIEWS
Started by Marshal Meru
I’m a designer working in a foundry casting mill liners where we have some designs for ball and SAG mils but we have design of other companies like Norcast, Outotec, FLSimdth all OEM's. We want to create our own design for liner for mill ball and ...
I’m a designer working in a foundry casting mill liners where we have some designs for ball and SAG mils but we have design of other companies like Norcast, Outotec, FLSimdth all OEM's. We want to create our own design for liner for mill ball and ...
Last replied to by
You might find these links interesting. These papers will take you through the basics.http://is.gd/aw84TWhttp://is.gd/qg8QFDhttp://is.gd/adw52TI worked for many years in Minera Escondida (BHPBilliton)...
You might find these links interesting. These papers will take you through the basics.http://is.gd/aw84TWhttp://is.gd/qg8QFDhttp://is.gd/adw52TI worked for many years in Minera Escondida (BHPBilliton)...
26
REPLIES
3267
VIEWS
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?
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...
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...
Give full answers