Page 35 - Curriculum Visions Dynamic Book

Mining for lode tin
This diagram shows how hot fluids rising up from molten magma injected themselves into the rock surrounding the magma.
To recover this ore, deep shafts were sunk, following the near vertical directions of the deposits. The veins were typically very narrow, perhaps no more than a metre wide, something like sheets of material. The network of shafts and horizontal tunnels (adits) developed in a mine were designed to reach these mineral sheets from a number of places.
Lode ore contains a variety of impurities including tungsten, sulphur and arsenic, most
of which can be removed by a stage of roasting before final smelting. Roasting arsenic-containing ores was a hazardous process.
Winding gear and steam engine house
Waste rock
igneous rock: a rock that has solidified from molten rock, either volcanic lava on the Earth’s surface or magma deep underground. In either case the rock develops a network of interlocking crystals.
lode: a deposit in which a number of veins of a metal found close together.
magma: the molten rock that forms a balloon-shaped chamber in the rock below a volcano. It is fed by rock moving upwards from below the crust.
metamorphic rock: formed either from igneous
or sedimentary rocks, by heat and or pressure. Metamorphic rocks form deep inside mountains during periods of mountain building. They result from the remelting of rocks during which process crystals are able to grow. Metamorphic rocks often show signs of banding and partial melting.
oxide: a compound that includes oxygen and one other element.
reduction: the removal of oxygen from a substance. Processing sheds
Abandoned shaft used for ventilation
 Tin mining in Britain has now all but stopped because the world price for tin is
too low to make deep lode mining profitable. Many
of the mines are now in a ruined state. Compare this modern picture with the etching on the left.
 A 19th-century deep tin mine.
Vertical shafts to connect the tunnels
Horizontal tunnels at various depths to reach the veins (lodes)
Metamorphic zone where the veins containing metal compounds are found
Granite, the once-molten source of the heat that produced the ore veins
EQUATION: Refining tin by reducing the tin ore in furnace containing coke
Tin dioxide + carbon (coke) ➪ liquid tin + carbon dioxide SnO2(s) + C(s) ➪ Sn(s) + CO2(g)
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