Rocks  bearing cassiterite are mined from the vein under ground are sent to grass (surface) where it is then processed in the mill to free the cassiterite  from the rock before going on to the smelter.The amount of cassiteriet or tin oxide found in Cornish mines is usually between 1 and 3 %

    The rocks enter the Mill via a wagon and are tipped into the ore feeder. The stone that is small enough pass through a grizzley

     The larger stones that didn't pass through the Grizzley have to go through a Jaw Crusher to reduce their size before rejoining the stones that passed through the Grizzley.

   The rocks after passing through the Jaw Crusher are reduced  in size to about the size of a marble

    The stone are next passed through the Californian Stamps and reduced to a size that is small enough to allow the separation of the tin oxide from the waste to be efficiently carried out in the following processes.

   The sand like particles are mixed with water and with the aid of a bucket pump the cassiterite and sand mix is moved on to the next stage in its separation.

  The Hydraulic Classifier separate the course mix from the finer mix and the flow then continue in the processing procedure to the equipment which is best suited to the mixture.

  These mixtures of slime flown around the Mill via launders

  One of the most impressive operations in the separation of the cassiterite from the sand can be seen when the slime passes over the shaking table.The casseterite being heavier than the waste sand flows in one direction while the waste flows in the other direction.

   The Acme Round Frame, probable the only working example in Europe and is more than 100 years old is still capable of separating cassiterite from the sand waste.