Hola Senior De Castro and welcome,

look at the CEMA wb site conveyor equipment manufactureres.org.

In a nut shell it alll depends on what you are going to screen and classifiy.

As an exapmple our anthracite coal is graded in the following sizes

Rice/ pea /chestnut /stove / and egg sizes,

There are standard screen sieves that measure product size that are available world wide.

The chief limiting factor is the size of conveyor you are using or plan on using and distance as this will determine your maximum product size which will be delivered through any transfer point and how much degradation of product you can tolerate.-with soft coal that is something you do not have to worry about as it is ground down to 30 mesh size or fed through a stoker boiler.

lzaharis ■

Senior Decatro,

In regard to your quartz problem, it is easily solved by reducing the crushed ore size-assuming your crusher can be readjusted to reduce the output size of the quartz ore- since quartz is laminar in nature this explains the flat ore that pieces that bypass size reduction or refered to as pan rock as we refer to it here-shale is laminar and this what we call pan rock. ■

Hi Jose,

Internationally recognized standards on mechanical sampling of materials in bulk specify that the width of a primary sampler should be three (3) times the topsize of the material, and that the speed of the primary sampler while it traverses the particle flux at the transfer point should not exceed 0.6 mps. Topsize is defined as the aperture of the screen upon which is retained no more than 5% of the material. When these criteria are met the mass of each primary increment is a function of the handling capacity only.

A cross belt primary sampler collects a primary increment of smaller mass because it does not have a critical speed. It would make sense to design mechanical sampling systems such that pairs of interleaved primary samples are routinely collected. This sampling protocol gives precision estimates for measured variable at the lowest possible cost.

Kind regards,

Jan W Merks ■

Jan wouldn't scooping a sample for a sample splitter do just as well after the primary screen and crusher or after the secondary screen? ■

Jose,

Manual sampling works well if the width and depth of the sampling scoop is 2.5 times the top size of crushed and sceened material. Selecting primary increments after the second screen makes sense. I don't know what quality characteristic is being measured but my suggestion to take a pair of interleaved samples stands. It gives powerful information to optimize the applied sampling protocol.

Regards,

Jan W Merks ■

thanks Jan I knew that was the way to go to keep it as simple and trouble free as possible.

lzaharis ■