An auger, made from stainless steel and of large dia. (300-400 mm), is used in combination with a hopper made from polyester resin and fibreglass compsn. reinforced with polyester and PVC. The hopper is made on an inverted mould with the surface treated to facilitate sepn. after moulding, using a process consisting of polymerising a number of layers of resin and fibreglass mat, fitting the auger trough (d) to it, and connecting it with further layers of the mat and polyester resin which blocking the end of the trough (b) with a nylon or teflon cushion.
