Greeting Krisnadharan,

regarding your inquiry you have a few decisions to make:

keeping the imported coal dry is the big one-as it helps in blending the coal and reducing ground water and surface water pollution to a minimum.

Designing the coal tipple to be linear in operation also simplifies its storage and maintenance by utilising a common tripper belt over the tipple hoppers and reducing complexity by reducing machinery needs and taking advantage of gravity to the fullest -think about it this way- skyscrapers concentrate every thing in a small area and with a large height/altitude.

You will see many examples of this when you research coal tipples if you decide to investigate this.

A very good example of this is the Wegmans grocery store chain warehouse in Rochester, New York USA-it is a skyscraper with a small area and many floors for storage of carloads of groceries.

Washing and sizing the coal types through a coal tipple should be number one on the list simply for a best practices for handing view point. It removes the dirt and other garbage out of the coal before use.

Mixing is easy as the coal can be loaded into belt feeders and the feeders can be proportioned for delivery rate to the conveyance -for example an auger or drum drier for adequate mixing and simplicity in cleaning the work areas.

You have to remember static electricity and spontaneos combustion are the enemy and plan for same by maintaing adequate grounding of all machinery and installing fire suppression at all points of conveyance and in the coal tipple if you decide to use one.

I suggested the coal tipple for the simple reason that it allows you to store the coal at a higher elevation with a small building footprint in relation to storage sizes after washing, cleaning, sceening and rock picking and it is easier to manage for delivery and mixing as all the components are in the coal tipple/ breaker building and the coal drops by gravity to the mixing areas.

The ten storage bins under the tipple building will be emptied easily with small narrow apron feeders under each bin to the mixing area using a common belt for the ten bins or multiple small belts under the bins feeders and can easily be regulated by the control of the speed of the apron feeders feeding the belts to the coal mixer auger or drum drier.

By elevating the storage cleaning and blending you will save space and have a smaller area to worry about. washing the coal and picking the rocks out will improve it burning quality and the bins will keep it dry.

Having an elevated coal tipple reduces total machinery needs as a single belt can feed the tipple and a single tripper belt can feed the bins after washing, cleaning, sizing and rock picking.

and you are taking full advantage of gravity to do all your work with little effort and much less machinery-no reclaimers, additional conveyors, front end loaders and fewwer personell needed to run things.

A huge factor is cleaning as any spillage that falls under the tipple is easily taken care of.

Having an enclosed tipple building where all the machinery is in one place and the coal is out of the weather which reduces the possibility of ground water pollution and waste water runoff as well.

Tthe coal wash water clarifiers reduce the chance for pollution as the water is reused and the coal sludge is either burned or buried in a proper land disposal area

The other option is having a small coal washing and screening plant with set of primary and secondary water clarifiers to allow reuse of wash water and a series of geodesic domes with central stacker reclaimers in each dome feeding a common underground conveyor belt gallery.

The domes can be fed by a common belt with a single moving tripper dumping into each dome. BY keeping the installation linear in design it simplifies installation and operation.

for the above:

<www.geometrica.com>

lzaharis ■

Dear Shri Krishnadharan,

Please specify the ship unloading and stacking rate and also the handling rate of blended coal. Because type of system will also depend upon the handling rate.

Deciding the right type of system for blending purpose is a serious techno-economical analysis and evaluation and the participation of knowledgeable people / organisation may be necessary.

You will have to also decide the required blending efficiency, batch size, sampling procedures, penalty (loss in earning) due to shortfall in the required blending, etc.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

If there is heavy rainfall then stockyard blending using winrows should be avoided in favour of blending out of bunkers. Rainfall is independent of the stockyard throughput. Consider that if you have adequate stockyard area you also have a large catchment area.

Do a mass balance of rainfall intensity plus the coal deposited, over any area, and you will appreciate that the captive free water between blending furrows is considerable. Putting that mess on conveyor belts encourages disaster for the onward processing.

Touble with blending bunkers is getting the particular coal into the designated bunker from the individual stockpile, its a bit of a Boolean process incorporating bin capacity, conveying distance & blend extraction rate.

Ten types of coal can be constituted into 9! equally partitioned blends for starters; which puts the decision squarely into the province of Quality Control/ Assurance. Then you will have to consider the addition of yet another constituent, bu....it. ■

John thanks for that explanation-thats why I explained the positives of having a large coal tipple or domes with a central gallery in my post.

I raise pint of Guinness or Bass to you my friend in praise for your explanation :^) ■

I guess my suggestions are out of the question with your set up, I totally agree with john about the problem with water and rainfall as you will have a huge mess. ■

We have to blend the cargo at the stockpile. [/B][/QUOTE]

As the Consultants jargon goes "Proceed at risk." ■

Could you tell kindly, in which proportions you want to blend the coals.

What ist the using aim of the blended coal? Coke ovens, power plants, briquetting plants etc..

Furthermore it is interesting to know: what is the size distrubution of the coals to be blended, since you will be risking burning of the coals at stock yard at certain physical and chemical qualities..

Thank you..

Dr.-Ing. Hayri ERGUN

Independent Consulting Engineer ■