go to www.donhad.com.au ......its a start. Good luck. ■

If you believe the web link:

http://en.wikipedia.org/wiki/Mill(grinding)

You will believe the specific surface refers to the composite granular surface area and its volume or mass.

While I believe this to be true, it does not give the complete picture of grinding efficiency. The efficiency is highly dependent on mill geometry, mineral strength and abrasive properties, slurry strain-rate rheology, ball size distribution, ore feed size distribution, ore rheology properties, mill internal configuration and means of containment at mill exit.

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Wikipedia:

To evaluate the grinding results the grain size disposition of the source material (1) and of the ground material (2) is needed. Grinding degree is the ratio of the sizes from the grain disposition. There are several definitions for this characteristic value:

Grinding degree referring to grain size d80

Instead of the value of d80 also d50 or other grain diameter can be used.

Grinding degree referring to specific surface

The specific surface area referring to volume Sv and the specific surface area referring to mass Sm can be found out through experiments. ■