The Dressing floor operation at South Caradon
This resurrection of the old South Caradon website is an excuse to bring back some of those basic paintbrush drawn .gifs of may years ago, (I loved Kawasaki green in those days), and also brush off my theory of the dressing floor material flow. Its a theory that seems to have survived the test of time. But off course if you have your own views on how the dressing floor operated, please leave a message.
The Seaton Valley housed the central dressing floors of South Caradon Mine, a complex of structures and buildings that has left a confusing legacy of terraces, low walls and rubble. No definitive description of the function of the structures exist but it is possible to attempt an interpretation of the remains that will give an insight into the traditional processes involved in preparing copper ore for sale.
Copper ore processing
The layout of a copper mines dressing floors was greatly influenced by the properties of its main ore Charcopyrite. This ore tended to be hard and brittle with the unwanted property of easily breaking into a very fine powder. Tin mines traditionally operated by stamping all the ore and then classifying and concentrating the crushed rock through a series of physical processes using water. Such an approach applied to Copper ore would lead to large amounts of the ore being carried through the system as fine waste. Instead series of manual processing, sorting and picking operations were utilised, leaving stamping for only the most hardest of rocks.
Sorting the Ore
Hand sorting was fundamental in reducing the amount or rock to be processed and it was started even before the ore was brought to the surface, much of the waste being left underground. At the dressing floors the rock was sorted in four main types.
- Deads: Containing no ore and was tipped in burrows
- Prills: Pure ore that required no further processing
- Drage: Ore mixed with gangue that required hand processing
- Halvans: Low value ore that needed stamping before treatment
Processing the Drage
It was this processing that gave a copper dressing floor its distinctive properties. Drage was dressed by a series of manually intensive tasks that took place in assorted lightly built structures crowded in valley bottoms. South Caradon used hundreds of employees to undertake this work, the majority of which were females called Bal Maidens. The large shed and area around it was the focal point for this work and its foundation area and adjacent cobbled spalling floors can still be seen.
In the later period of the mine’s life Bucking and Jigging had been mechanized using a steam powered crusher and jigging machines in one of the sheds. The bucking mill was mounted powered by the
stamps steam engine, and was located in the building to the north of its flywheel.
Processing the Halvans
Halvans were treated like tin ore and the Halvans floor resembled a smaller version of a tin mine’s dressing floor. The rock was first crushed in the set of Cornish stamps before passing through a set of tanks and buddles to separate the denser ore from the gangue. Little remains of South Caradon’s 24 head of stamps, or its engine apart from the bank upon which it stood, some fragments of wood and the flywheel loadings.
Of the dressing floors only a small parts of some of the tanks remain exposed, the rest has been buried beneath landfill of alluvial deposits.
Flow of material through the dressing floors
I have taken the suggestions of various publications combined them with the photograph from the Neil Parkhouse collection ( as reproduced in Webb and Geach), and applied a simplified Copper dressing model to arrive at this suggestion. Since the production of this diagram I have produced a map of the tramway network that supports and expands on this interpretation of the remains.
Two flows of raw material are shown in this diagram. Drage processing is in red and Halvan in white, some material is shown returning back from Jigging for re-bucking or stamping.
The Drage processing flow
Hand sorting, ragging, spalling, cobbing and possibly jigging were most likely carried out on the cobbled floor area and within the large shed. Bucking was probably a powered process using the crushing mill and jigging was also powered . I have therefore suggested that the lower shed was used for jigging, this being supported by the tramway layout.
The Halvan processing flow
The lower Seaton Valley area is described by CAU as being used for waste treatment. This is undoubtedly the Halvan floors, and old OS maps show what is probably buddles and tanks (trunks) in this area. The fines for this area would have been produced from by the stamps, and again the tramway layout supports this suggestion.This lower floor area has disappeared under tipped landfill and alluvial mud leaving little evidence.
The Trevithick Society have reprinted Webb and Geach’s ‘The History and Progress of Mining in the Liskeard and Caradon District’; a reprint that includes the fascinating Niel Parkhouse collection photograph.