As well as the underground workings, the mine site includes one of the most complete set of remains in Cornwall of an early 20th century dressing floors. These floors were constructed between 1912 and 1914, but saw hardly any use before the mine closed. During operation the floors comprised a gas suction engine to provide power, 2 head of Holman pneumatic stamps, Frue vanners, tables, kieves and two buddles.
The lack of sulphide in the ore meant that calcination was not required. The layout of the floors is typical of the period and the buildings would have been constructed of stone bases with timber frame and timber or corrugated iron walls and roofs.
The floors were served by means of a tramway from a short inter-level below No.1 Level. The tinstuff was fed into a crusher and hopper mounted adjacent to the gas suction plant. This in-turn fed the pneumatic stamps, which fed into the Frue vanners and tables and then on to the kieves and buddles. There appears to have been no cuttings pits, so the tailings must have been deposited into the stream. The black tin product from the mine was transported by horse and cart to Gulval for smelting.
Schematic of the dressing floors at Rosevale Mine (Adam Sharpe)
Section of the dressing floors at Rosevale Mine (Tony Bennett)
The equipment typical of the period is shown below:
Plan of the dressing floors at Rosevale Mine
Various images of the remains of the main dressing floors (2010)
The original set of Cornish stamps lay adjacent to the stream below the portal of No.2 Level and were driven by waterwheel, approximately 24 feet in size. These stamps were subsequently replaced by the pneumatic stamps and the waterwheel was then modified to belt-drive an air compressor. The waterwheel pit and the foundations of the compressor house are still evident.