Copper concentrate can have a range of compositions and moisture contents but is invariably dense and of relatively high bulk strength so the flow properties have to be determined of the material in the worst condition to be handled in order to design the feed hopper for reliable discharge. Having determined an optimum feed hopper geometry, the load on the outlet acting on the feeder has to be calculated and the shear conditions for extraction assessed for both starting and running loads. If you are not experienced in these fields, it would be prudent to engage a specialised supplier of this type of equipment ■