Hi Liam,

How many filters are there on these 2 belts?

How is the alternative 80th^-1 diverted in the first place?

Belt filters should perform better than 22% moisture retention.

Slumping is natural with wet residue and deformation continues as the crud passes over the downstream rollers. If you only get spillage at the transfer points and the design should handle at 70% full, but doesn’t, then you might like to ask your process instrumentalists to re-assess the operation because these belts are overloaded and there is going to be spillage whatever moisture content can be achieved. Just do some sums to see what a perfectly dry belt would carry and throw it back in their faces. (Nearly forgot to add the extra ‘e’ in faces.)

If we were talking press filters it would be a simple case of interfering discharges but your case sounds like the standby unit has been brought into service to supplement throughput. Ask around.

Rest easy, material that slumps won’t bridge readily but you are right in expecting a longer drop to result in more slumping.

If you are going to double the throughput you will have to jack up the revs more than double. If the existing spillage situation is long in the tooth then be prepared to replace idlers very soon and then mention that all idlers will need upgrading eventually. ■

Something is definitely wrong with your tailing's as they act exactly

like semi liquid manure from a free stall dairy barn.

As john said there is something wrong.

I have seen sewage sludge and coal sludge that looked better than that after going over a vacuum filter drum.

I would start at the beginning and ask if you need alum or hydrated lime to make the tailing's

more dense first(provided the quick lime or Alum cannot create a chemical reaction creating combustion.

Second I would check the filter fabric for its condition, when was it changed last???? It does wear out you know.

Third is the pressure gradient, how many inches of mercury are you

drawing to create the pressure gradient??? at how many locations???

Is the blower using a water mist to create a chilled temperature to increase its efficiency-

colder air is more dense providing more usable energy to an application where a blower is used.

Fourth, when was the blower last rebuilt or checked to proof its adequate creating

of a pressure gradient to do the work.

Was the blower properly adjusted for the altitude of the plant?

How often are the air filters changed?? are you using an oil bath precleaner?,

if so how often is the oil bath checked for adequate oil level or cleaned the dirt bowl.

If you have paper air filters the pop up tattle tales cannot be trusted to work properly!!!!!!!!!!!

The Dwyer brand of manomometer's work very well

If the blower is belt driven- has anyone checked the belt tension or replace belts recently and

\adjusted them properly with a V-belt tension gauge???

Have the belts been checked since then if they were changed??

How often do you change the blower or the vanes if it is a vane type of blower.

Has anyone checked for pressure gradient leaks with soap bubbles?????

Lots of information is still missing in this hypothesis and experiment

to provide us/you with a successful conclusion.

Help us, to help us help you!!

If all else fails you need very large manure spreaders that have liquid proof gates. ■

Originally Posted by cementhead

Thank you gentlemen for the input

Please note that there is nothing wrong with the belt filters. They operate on a very simple principle.

The slower you run the more water the vacuum pumps will remove solution from the tailings.

They faster you run the less water gets removed. If you now start to wash the tailings to recover cyanide,

gold and silver they you have that much more solution to remove. There are currently running 2 x 64m2 filters

and 1 x 113 m2 filters and the project is adding a fourth 113 m2 filter. One machine will be stand-by.

If they run at 18% humidity in the discharge tailing their capacity is about half of that when running at 22%.

They currently run somewhere in the middle. 22% was the worst case scenario.

If bridging is not going to be a problem then I will center the material better I also have to work to center the

belt better as their belt alignment methods leave a lot to be desired.

The arrangement is that the two smaller belt filters discharge onto conveyor 1A and the two larger belts discharge

onto conveyor 1B. Both 1 conveyors discharge onto conveyor 2 with 1A being closest to the tail.

My conveyors are all horizontal or down hill. Load points are horizontal although I thick you would have a hard time

making this material roll back.

thank you again for the input

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You came aboard asking for help. Unless I am mistaken you have not taken the time

to answer or provided one, why not???? You also stated the system is using more liquid to

extract the metals REQUIRING more filtration and greater pressure gradients.

Any increase of discharge speed when one wants to increase reclaiming of chemicals and

metals requires an increased pressure gradient and or replacement filter fabric OR additional

filtration using pressure gradients.

You have asked and answered your own questions essentially. ■

Are you heap leaching and or using a clarifier to reclaim the sludge??

your physical plant needs a lot of work and your design plans for a belt speed increase

may be a moot point with the loading factor on the belts now as your belt

has to be able to carry the material and not run away with the material

and have it skitter off the belt due to belt speed.

When you mean running down hill are they literally sloped below zero degrees or are they transferring to a

second conveyor on a lower horizontal grade?

Are you saying your conveyors are capable of moving laterally using a wheeled undercarriage like a stock

piling conveyor or is a belt magazine being used allowing them to squirt out or retract so to speak?

Slurries always have entrained air the act of agitation creates air bubbles.

A minor detail, but when one is dealing with blasted rock or other ores the increase in volume per cubic foot

is due to an increased surface area of material; the generic term is "rock bulking factor"

Your sludge is too wet and you need to go back to the filter beds and the filter fabric as it is most likely plugged.

is the filter fabric washed clean at anytime after the filter cake extraction?????

The piping used to create the pressure gradient under the beds may be plugged with silt from the sludge.

Start with the simple things first. ■

According to the photos the conveyor is hopelessly overloaded and no amount of training will solve that. Bolts are missing from the scraper mounting etc. etc.

You shouldn't be letting the forums know that your mine prefers to leave cyanide liquor in the tailings on purpose. Even in Indonesia you'd be shut down immediately (I got a mine in Jampang Kulon shut down for that very reason some 4 years back!)

The process numbers don't add up. If you want to double production you have to double filter output, safe filter output at that, before even thinking of putting NEW conveyors in.

Process metallurgists work, by admission, to 10% and leave the rest to ore body fluctuations, metal prices and the like. That's in the good times.

This situation reads as a mine which is cutting corners which have already been completely rounded. Your outfit ran the job into the ground and now expect to increase production on another shoestring.

Process cocked up in the first place and they should be the ones to un-cock it up. But they pretend it is a material handling problem and some all pleasing conveying engineer jumps at the chance to solve the problem; struggles and then gets blamed by the process tossers who caused all the trouble in the first place. It's called mine management in polite society.

I bet there is nobody writing an EIA on this one! ■

Originally Posted by johngateley

According to the photos the conveyor is hopelessly overloaded and no amount of training will solve that. Bolts are missing from the scraper mounting etc. etc.

You shouldn't be letting the forums know that your mine prefers to leave cyanide liquor in the tailings on purpose. Even in Indonesia you'd be shut down immediately (I got a mine in Jampang Kulon shut down for that very reason some 4 years back!)

The process numbers don't add up. If you want to double production you have to double filter output, safe filter output at that, before even thinking of putting NEW conveyors in.

Process metallurgists work, by admission, to 10% and leave the rest to ore body fluctuations, metal prices and the like. That's in the good times.

This situation reads as a mine which is cutting corners which have already been completely rounded. Your outfit ran the job into the ground and now expect to increase production on another shoestring.

Process cocked up in the first place and they should be the ones to un-cock it up. But they pretend it is a material handling problem and some all pleasing conveying engineer jumps at the chance to solve the problem; struggles and then gets blamed by the process tossers who caused all the trouble in the first place. It's called mine management in polite society.

I bet there is nobody writing an EIA on this one!

===========================================================================================

GEE WHIZZ, John you robbed me of my thunder already:^(----- HAHA Bravo, Bravo,

I am hoisting a glass of Coca Cola "With actual sugar" to you in good cheer. ■

Originally Posted by cementhead

Wow are we really off track. I am not sure is I have aggravated everyone or what. I would like to get back to the main point of the original post in a minute but first will address a couple of items;

The mime is not heap leaching. They dry stacking.

I hope I did not mislead you but please don't be making assumptions as to the amount of cyanide in the tailings. The cyanide is used up throughout the process and there are multiple washing stages in the plant to ensure that this occurs. This mine runs with ppms in their tailings that are well well below their permit levels and are reported and tested on a continuous, I believe daily basis. Additional washing is performed when the water balance permits and this can save money in solution recovery. Again this is off the mark of conveyor capacity.

I know the conveyors need money and love and there is a budget to fix a lot of the problems if 24" conveyors fit the future tonnage. It is not that the plant has been run into the ground but more that personnel there did not know how to operate and maintain their conveyors as this is such a small part of their regular operation they neglected it. They now realize this is a problem and want to address it. Kudos to them....

I did make one error in my first email my apologies. I said I want to take the conveyor up to 350 mtph but meant to say 350 fpm

We can continue to find all kinds of problems with my posts or I am kindly requesting that we can address the main question

Can a 24" conveyor move 178 mtph (normal flow) of tailings (this includes the 20% humidity)? When they are one solid mass, the tailings density is 1.95 to 2 t/m3

If you add a bulking factor from the cake breaking up off the filter a very very conservitive density could be 1.75.

I am looking to design for 230 mtph as a peak design flow and account for surges.

The pictures show the tailing on a 24" conveyor with approx 19% humidity and it was running at 80 to 90 tph and 250 fpm. Pictures show the highest surge points

My calcs show that 24" conveyors work by you are right the pictures would seem to indicate differently. As I increase tonnage any surges should level out slightly.

So the question is can a 24" standard conveyor convey this quantity of material?

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Liam your vacuum filters needs work period, then you can work your way forward.

I would replace the fabric, clean the filters with a steam cleaner clean or change

the piping for the air passages

2. check the circuit breakers for the blowers for proper ground and resistance

a. check the electric motors for adequate resistance and voltage

b. examine the wire splices for the motors if a wire to wire connection

is used with butt connectors.

c.check the motor cooling fans to see how much dust

is on them if they are not sealed and clean them if needed.

d. steam clean the motor shells if motors are of the sealed type.

You may need new electric motors as well as blowers as they really work creating

high amperage's in pressure gradient generation.

Fabric replacement, blower replacement or rebuilding, cleaning the filter bed

with a steam cleaner (preferably replacing) the piping used for creation of pressure

gradients- Victaulic pipe and joints are best for this.

If the country and its environmental management department that regulates your mining and

smelting operation is happy with the results of the residual PPM metals testing OK: just remember

we are on the outside looking in and the thread and posts are not terrible and in need of deleting.

The conveyor is still going to be an issue especially with the bulking factor as the sludge is still

too wet and increasing the volume is not advisable with this width of conveyor as you will spill

more material at a greater speed of travel.

A much longer filter press is about the only way your going to handle this mess as the sludge will be a simple

dried sheet or at least something that comes very close to it. Saying that I am not sure if the plant

owner is willing to retool.

Many of my own questions are still unanswered.

No one is trying to hinder you Liam we only want to help, but sadly everyone but you is too far away from

the football pitch to coach you. ■

Part of Liam's reply:

Please note that there is nothing wrong with the belt filters. They operate on a very simple principle. The slower you run the more water the vacuum pumps will remove solution from the tailings. They faster you run the less water gets removed. If you now start to wash the tailings to recover cyanide, gold and silver they you have that much more solution to remove. There are currently running 2 x 64m2 filters and 1 x 113 m2 filters and the project is adding a fourth 113 m2 filter. One machine will be stand-by.

Part of my reply:

You shouldn't be letting the forums know that your mine prefers to leave cyanide liquor in the tailings on purpose.

My reply was prompted by "If you now start to wash the tailings....". To me this meant that because of filter performance limitation the mine was not starting to wash the tailings. I accept Liam's side of things after his further clarification. ■