VISIT TO GEEVOR TIN MINE, CORNWALL, JULY 2005

This summer I had the opportunity to visit the Geevor Tin Mine Museum, which is located at Pendeen, about six miles NNE of Land’s End.

Geevor is spectacularly located on the cliffs overlooking the Atlantic Ocean, and this extensive site is now the largest historical mining site in the UK. The entrance fee covers admission to the surface structures and an underground guided tour. The museum contains a comprehensive collection of mining items, a good mineral display and a large collection of photographs of the mine and miners at work, plus an amazing 3-D display of the underground workings, which once stretched out far under the sea. There is also an excellent audiovisual display. Geevor was one of the last working tin mines in Cornwall, closing in 1990, and although some of the surface equipment was scrapped at closure, enough remains to make a very interesting tour, including the compressors and winders, the drill shop and enough remaining items in the mill, together with good display boards, to make sense of the complex ore treatment processes. The Tin at Geevor was present as Cassiterite (Tin Dioxide), accompanied by various Iron oxides, Pyrite, Chalcopyrite and lesser quantities of Tungsten and Arsenic minerals. After milling and magnetic separation to remove Iron oxides and bits of Iron from the ball mills, an ingenious chemical flotation process was employed. The crushed ore was mixed with Pine Oil and Potassium Amyl Xanthate, which sticks preferentially to the sulphide ores and makes them rise into the layer of bubbles and scum, which was then skimmed off, leaving the Tin ore concentrate behind. This was further refined by gravimetric separation on large washboards, prior to sale as high quality concentrate ready for smelting.

The guided underground tour (hard hats supplied by Geevor) uses an adit into the long-abandoned Wheal Mexico mine, an 18th Century mine that was rediscovered in 1995. The tour gives an excellent impression of the harsh conditions under which the earlier miners worked. They had to purchase their own candles, and the levels of poverty were such that many miners extinguished their candles at meal break, and ate in the dark! In later years, rotary hammer drills were introduced, but at least had the benefit (this being hard rock mining) of having water-cooled drill bits, so no dust was produced, although the downside was that the miners worked in very wet and hot conditions.

An excellent site - highly recommended.

Chris Swan