High rate screening

Posted in: , on 17. Sep. 2008 - 14:46

we are about to start extracting sand for washing and screening at a rate of 1200 tph,

the probelm we have is conglomerate lumps of sand mixed with our raw material, we would like to screen up to 1200 tph on moble screens to remove the conglomerate and the oversize.

issues, conglomerate can reach 350mm, up to 15%

our washed product is minus six mm,

we want to screen down to as near as we can get to six mm,

therefore the product belt on the screener must be able to take a high tonnage of material.

can anyone reccomend a good highoutput screener for this?

Re: High Rate Screening

Posted on 17. Sep. 2008 - 04:50

Originally posted by jamesward

We are about to start extracting sand for washing and screening at a rate of 1200 tph.

The problem we have is conglomerate lumps of sand mixed with our raw material, we would like to screen up to 1200 tph on mobile screens to remove the conglomerate and the oversize.

issues, conglomerate can reach 350mm, up to 15%

our washed product is minus six mm,

We want to screen down to as near as we can get to six mm,

therefore the product belt on the screener must be able to take a high tonnage of material.

Can anyone reccomend a good highoutput screener for this?

Ooooh my buddy George Baker is going to love you;

I will start by asking what type of sand are yall screening? is it from sea bed dredging? only because sea sand does not like concrete mixes.

The problem is the sand auger at the end of the screen deck-let me explain-they run very slowly through a gear box due to the weight of the sand and water.

The sand flows to the bottom of the screener simply by gravity and mass movement and the decline angle of the screen

A twelve hundred ton per hour portable is possible to build of course but a 48-60 inch belt will be needed to carry it(the sand) away.

But you will need 600-1000 volts for the system if all electric.

The other problem is flow across and down the screener-george will tell you the same thing.

If you have a 12 by 24 foot portable screener with 3 or four decks for the over size you will have lot of screen blinding with that small a screen fabric at the bottom.

You would be money ahead by purchasing a permamanent small screener with a sand plant but the problem is water as fine sands(mason sand, concrete sand) are usually done with a stationary plant due to plumbing issues.

A big portable flotation cell drilling mud set up-which is a water well/ oil well drilling mud cleaner would be really what you want as they are portable and self contained and are trouble free as they have multiple desilting cones for sand and screen etc. and can cut down to that size of 6 MM and hold fresh water for reuse and they are fully portable too.

It will take a bit longer but it will be easier to maintain and can be run around the clock with little maintenance and in your part of the world they are in use all over the place too so it will be easy to see one in use.

Re: High Rate Screening

Posted on 18. Sep. 2008 - 08:03

the sand is natural deposit sand.

the washing plant is already in place form a company in ireland.

we want to screen at source,

there is a forty km trip from source to plant so we want to haul as much product type material as possible, no point hauling oversize material, waste of money.

we have been looking at finlay for high rate screener, just wanted to see what else there is out there.


Sand , Sand, Sand

Posted on 18. Sep. 2008 - 03:20

You did not mention if it was silica sand but;

Moving the deposits sand 40 kilometers to the plant is a given so I see no point in screening it before hand as you will be doubling your work period!

How big is the deposit? the larger the tonnage the more economical a capsule pipeline becomes.

You will be able to rent a very large drill mud cleaner or cleaners on site at the in situ plant for your job, you will have a cleaner sand product cut to the right size and you will be money ahead without needing a vibrating screen.

What if any infrastructure is available at the deposit site such as water, electrical utilities, actual road work?

You will need 4160 to 480-600 volt power for the screen and the screen feeder etc.

Short of a heavy trommel screen(and losing a lot of actual product as a given) you few options for your sand deposit in my opinion- see above.

A trommel screen rotates and carries away the oversize/garbage/junk at the same time.

Do you own the deposit or is it owned by the kingdom with you having a mining consession royalty per ton? I ask simply to clarify the cost per ton or yard/cubic meter issue of the project

Installing a narrow gauge railway with "Difco side dump cars" would be an excellent way to move huge amounts of sticky wet material- as an example please investigate the work done by the Union Pacific Railroad as a result of last winters mud slides.

The next best option or better option"in my opinion and experience" is a small capsule pipeline(24 inch) which would be even more economical than rail or truck as it can be run around the clock with little maintenance as only one person is required per million tons of material loading and dumping is done with minimal equipment

A deposit of 100,000 tons or more of ore and one mile or more of distance traveled is required for reasons of simple economy for the system; that said fuel prices are another factor where energy

can be recovered with snychronus electric motors on the return empty trip to feed electricity back into the system. and reduce the energy costs considerably and by returning the waste clay to the deposit site for disposal.

to see an actual capsule pipeline system in daily use since 1983 google (Karaswa limeston mine) a mtisubshi capsule pipeline was designed and built from the ground up to replace a railline; the original railbed was used to bury the capsule pipeline.

The mitsubishi system uses a (single pipe) maximum of three capsules but the system designed by brink weaver at pnuetrans can use up to five capsules in a capsule train at once and recover enenrgy using synchronus motors.

The capsule trains can consist of up to 5 cars in a train and a single tube system is the least expensive(easiest/fastest installation) method of transport.

A large number of capsule trains can be used in a single tube allowing one to have huge economies of scale eliminating haul trucks or rail and the additional fuel, labor and capital used to operate allowing for much lower overhead plant costs

You have the room and distance to do this very economically as it only requires one maintenance person per million tons of mined material.

The capsule trains run at 25 miles per hour with air pressures of 3 to 5 PSI and can be run faster and the sand will weigh more than the individual capsule zeroing out the weight of the actual capsule in the design of the system and eliminating the capsule weight as all that will be carried in the tube is the sands weight of product being more than the individual capsule and making it that much more efficeint as the greater the ore weight the more mass is propelled by a smaller amount of captive air.

By stock piling the sands prior to screening you can have the efficiency of scale on your side. The example I always give is the typical power generating plant here in the states-a ninety day supply of coal is generally stockpiled in the event of shortages/weather problems/labor strikes/national or regional disasters etc.

It is no different than transporting crude oil and storing it prior to


Disclaimer: I do not represent any of the companies mentioned above in the text. I am simply interested in capsule pipelines and railroads.

Re: High Rate Screening

Posted on 26. Sep. 2008 - 09:21

Finlay is right for the job. There is also a neighbour of theirs called Powerscreens.

Fifteen percent is a lot to throw away if some of it can be broken down. Is your 15% talking about the 350mm zone because if so then there is a lot of intermediate sized material as well and this would reduce the screening efficiency.

If you fitted an attritor cell on a gravel pump and recirculated the middlings from a two deck screen you might/should get a better product yield.

Re: High Rate Screening

Posted on 27. Sep. 2008 - 02:48

Might I suggest you look at the General Kinematics screen? It uses 1/5th the electrical energy required by direct drive screens of similar size and does not dampen under load.


You can learn more at our website, here is the link to the screens... click here .

These can always be mounted to a trailer... we can custom design the piece of equipment or an entire system to meet your process requirements.

Thank you,

Thomas Musschoot

General Kinematics Corporation

5050 Rickert Rd.

Crystal Lake, IL 60014

Ph. 815-455-3222

Re: High Rate Screening

Posted on 28. Sep. 2008 - 06:36

Powerscreens have already been suggested so a double recommendation ought to get us a medal. Nothing wrong with Finlay though and their screen advice can be taken safely. The job is in Doha, where Sinbad sailed out of. Plenty of sand but not the sort for building.

What will happen to the 180tph rejects if they are screened on open circuit? Are you using a boiling box to break down as much oversize as possible? A bit of sophistication on the circuit will soon give the payback in increased yield with that sort of material.

Washing Plant

Posted on 10. Dec. 2008 - 09:25

If you are simply washing the material, you may want to consider a Terex Simplicity Wash Plant. They offer them in several different sizes with GreyStone 36x25 screws. They are popular in the states for washing aggregates.