What is the alternative for comparison? ■

As John has stated what is the alternative?

The problem with mined stone is dust is created no matter what the extraction method.

What is the broken size of the ore?

The other part of the alebra problem is the hardness of the limestone in question.

No matter what you will have sized ore ore rubbing against ore against method of extraction and it creates fines and five terms in the algebra problem.

What it comes down to is how much loss from fines you are willing to to tolerate.

If the client wished he could sell the fines for agricultural lime feed stock. ■

First and foremost you have not said a word about the limestone type or how it is mined or if it is in a multiple seam deposit with other rock covering it.

Until you do a sifting seive analysis with the limestone you will not know how much is generated.

You might as well start by purchasing a sample splitter and a good sample scoop with a long handle to take samples off the takeaway conveyor after the reclaimer head and go from there unless you own them already.

If you have a sample splitter buy and electric powered sifting sieve, they are very easy to use and can be purchased world wide from any reputable scientific supply house-I use Lab Safety Supply myself.

The next step is to decide how many microns of fines you are willing to tolerate-30-90 or more-dont forget by slowing down the reclaim head also reduces fines a little bit- but it all depends on your limestone and its Rockwell or Mohs test performance if youy have done that already

Your turn john and george, if I missed anything my apologies. ■

It will simply depend on what the customer will tolerate-i.e. if no water is used a lot of dust will be created period.

As a poor example rock salt may generate 5-10 percent minus thirty mesh.

If your client is not helpful what is the point of asking anything? ■

Dear Shri Banerjee,

In totality, following are the reclaiming methods :

1) Pushing by bull dozer and feeding in to hopper

2) Pickup by pay loader and dropping into hopper

3) Dragging the material by scraper reclaimer or other machine and further conveying.

4) Picking by bucket of the bucket wheel for further conveying

Analyzing the reclaiming process of aforesaid nature, the material degradation magnitude would be as below :

1) Highest (say D)

2) Somewhat more than minimum (say B)

3) Less than the highest (say C)

4) Minimum (say A)

If you want to have a minimum degradation then only equipment are serial no. 2 and serial no. 4, in accordance with engineering analysis. The pay loader will have capacity limitation plus interrupted or somewhat clumsy operation and its wheel will crush the limestone during its movement. Thus as can be visualized, bucket wheel reclaimer will cause minimum degradation. So, in my opinion you do not have an option other than this on degradation (breakage) consideration.

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 25871916 ■

back to this-it also depends on the method of mining and explosive used if any so the dust and fines is still an unknown. ■

Fines exist already. Disturbance causes some of the fines to be entrained by the air through which the material passes. These entrained particles are called dust. If you don't know how many fine particles exist; nor their trajectory, then you cannot predict the expected dust concentrations.

Since capturing the dust at the bucket wheel might be impractical, depending on the extent of your client's concern, it seems appropriate to suggest wetting the pile.

A bucket wheel might grind the odd few stones together. It is hardly likely to break many. The interparticle friction occurs while the bucket is in the pile, digging, sort of. When the burden breaks into open air the digging has already stopped. Dust is mainly due to the lifting of the already existing fines.

What degredation does your client expect downstream?

Where do you find these clients? ■