The mill at South Crofty Mine, Carn Brea. The cam-shaft gallery of the 60-head Californian Stamp battery. A stamp is a device for crushing rock, calfornian stamps were made of steel and mounted in sets of five. The wall rock in South Crofty is pink granite composed of quartz, orthoclase, plagioclase and muscovite. The plagioclase is often completely kaolinized and sericitised. The veins are mostly quartz-chlorite and fluorspar-quartz-chlorite rocks and haematitic material is abundant. The tin ore is cassiterite. The Carn Brea area embraces the northern slopes of the Carn Brea granite and the thermally metamorphosed killas and greenstone that overlie its northern flank. The numerous lodes in the area trend east-north-east and are related to extensive shattering of the rocks, the latter contemporaneous with the injection of the ores but probably earlier. Photo P208029. Reproduced with the permission of the British Geological Survey ©NERC. All rights Reserved.
This photograph is by carnkie and was uploaded December 9th 2009. © carnkie please do not copy or distribute without prior express permission.
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