The earliest prehistoric tinners would have had some limited rich alluvial deposits available to them which need only have been separated from the associated waste by washing the deposits in a pan or similar item. However, from the beginning, it is likely that lumps of rich cassiterite were found which would have yielded good tin with very little additional work. Extensive work by R. Penhallurick (1986, 151) has indicated that from the Bronze Age, tinners in Cornwall were engaged in shallow mining. This activity would have provided tin ore which had to be crushed in order to release the cassiterite. There is at present no evidence to suggest that prehistoric tinners employed mills to crush their ore, and although negative evidence is far from satisfactory it is more likely that the relatively small quantities of material could have been dealt with by initially pounding the rock into pieces and then reducing it further by putting it through a hand mortar, similar to those used for grinding cereals. It is likely that tinners having an abundant supply of rocks on which to pound the, ore never worked on one particular stone long enough to produce the hollows characteristic of medieval stamping. In addition, not enough is known about the nature of the hand pounding of ores to suggest that any any hollows would have been produced, since the depressions are a consequence of a stamp falling exactly on the same spot, whilst if hand stamping had occurred it is more likely that the entire surface of the rock would have been utilised leaving no significant areas of marking on the stone. Another potential interpretation concerns the use of rotary mills, already employed to grind cereals during this period, as possible cassiterite mills which utilised existing technology. Confirmation of this hypothesis , however, will only be forthcoming as a result of detailed micro-wear analysis of such millstones.
Thus, evidence for hand crushing of ore is likely to be very difficult to locate, but given that some limited mining was occurring and no stamping mills have been found, it seems likely that manual preparation of the ore existed.
The Early Tin Industry 