Ann: Quarterly Activities Report SEP 2009 , page-17

Robertka
when you say battery I am guesseing you are referring to something like a 5 stamp press, I have only seen them work in museums, I dount if any western country has used one for a hundred years in production.

On the bottom of a jaw crusher there is a plate that changes the aperture size that the ore can flow out of the crusher as minerjoe referred to by closing up the plate it crushes down the ore to a smaller size untill around 80% of it passes the size you require. You are right the jaw crusher will crush effectively down to around 10mm but it will crush ineffectively to a smller size by closeing down the outlet we had a jaw crusher on the farm for crushing alluvial grey wackie rock for local roading contractors
There are also cone crushers its possible they may be more effective at crushing to a smaller size.

over 30 grams a ton is impressive
Also when you say sand at 50 microns that is only 1/20 of a mm and I would think is more the size of silt or clay particles not sand going from the little I remember at uni for soil science, sand may have a different meaning though in a mineing context I guess