It helped to break up the tin-bearing particles ..

Tin has a high specific gravity - in other words, it is heavy. The tin particles are heavier than those of the rock in which they are trapped, so their weight will enable them to settle out in a stream of flowing water before the lighter waste particles are washed away - like an ebb tide leaving large stones high up on the beach and small pebbles lower down. This principle, called GRAVITY SEPARATION, was known to the earliest tin streamers, and is still the most efficient way of recovering tin.

...and was equally important as a means of power

An OVERSHOT WATER WHEEL is turned by the weight of water poured on to it at high level.

You will see this kind of wheel powering the Cornish stamps.

A DIPPER WHEEL is a simple form of pump, in other words a method of raising water or slurry to a higher level.

You will see these at work in the Slime Plant.

The RAW MATERIAL at Tolgus was sand from the Red River, so-called from the colour of its tin- and iron-laden water, sand which had already undergone considerable processing elsewhere, yet still containing enough tin to be worth re-treating. It was stored in the ORE SHED to be dried out.


The dried sand is fed by conveyor belt into the SCREEN WASHER to be washed; oversize pebbles are rejected and travel along another belt to the side

Both fresh water and slurry are carried round the Mill by means of open wooden pipes called LAUNDERS.

Foreign bodies like leaves are removed by constantly sweeping with brushes made of heather an example of the tin streamer's ingenuity in making use of nature





From the Washer the slurry is pumped to a HYDROCYCLONE, which splits it into large particles (sands) and very fine particles (slimes).

Immediately below it is a series of curved SCREENS, which grade the sands according to size.