Tin mining 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
2219 aluminium alloy toughness, is weldable and resistant to stress corrosion cracking, therefore it is widely used in supersonic aircraft skin and structural members. The Space Shuttle Standard Weight Tank was also fabricated from the 2219 alloy. Alternate designations include AlCu6Mn and A92219. It is described in the following standards: The alloy composition of 2219 aluminium is: 2219 aluminium alloy 2219 aluminium alloy is an alloy in the wrought aluminium-copper family (2000 or 2xxx series). It can be heat-treated to produce tempers with higher strength but lower ductility. The aluminium-copper alloys have high strength, but are generally less corrosion resistant and harder to