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Tin mining began early in the Bronze Age, as bronze is a copper-tin alloy. Tin is a relatively rare element in the Earth’s crust, with approximately 2 ppm (parts per million), compared to iron with 50,000 ppm. ==History== (詳細はBronze Age around 3000 BCE, when it was observed that copper objects formed of polymetallic ores with different metal contents had different physical properties.〔 〕 The earliest bronze objects had tin or arsenic content of less than 2% and are therefore believed to be the result of unintentional alloying due to trace metal content in the copper ore〔 〕 It was soon discovered that the addition of tin or arsenic to copper increased its hardness and made casting much easier, which revolutionized metal working techniques and brought humanity from the Copper Age or Chalcolithic to the Bronze Age around 3000 BC.〔 Early tin exploitation appears to have been centered on placer deposits of cassiterite.〔 〕 The first evidence of tin use for making bronze appears in the Near East and the Balkans around 3000 BC.〔 It is still unclear where the earliest tin was mined, as tin deposits are very rare and evidence of early mining is scarce. Europe's earliest mining district appears to be located in Erzgebirge, on the border between Germany and Czech Republic and is dated to 2500 BC. From there tin was traded north to the Baltic Sea and south to the Mediterranean following the Amber Road trading route. Tin mining knowledge spread to other European tin mining districts from Erzgebirge and evidence of tin mining begins to appear in Brittany, Devon and Cornwall, and in the Iberian Peninsula around 2000 BC.〔 These deposits saw greater exploitation when they fell under Roman control between the third century BC and the first century AD. Demand for tin created a large and thriving network amongst Mediterranean cultures of Classical times.〔 〕〔 〕 By the Medieval period, Iberia's and Germany's deposits lost importance and were largely forgotten while Devon and Cornwall began dominating the European tin market.〔 In the Far East, the tin belt stretching from Yunnan in China to the Malay Peninsula began being exploited sometime between the third and second millennium BC. The deposits in Yunnan were not mined until around 700 BC, but by the Han Dynasty had become the main source of tin in China according to historical texts of the Han, Jin, Tang, and Song dynasties. Other regions of the world developed tin mining industries at a much later date. In Africa, the Bantu culture extracted, smelted and exported tin between the 11th and 15th centuries AD,〔 in the Americas tin exploitation began around 1000 AD, and in Australia it began with the arrival of Europeans in the 17th century. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tin mining」の詳細全文を読む スポンサード リンク
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