Tin sources and trade in ancient times Bantu culture of Zimbabwe are known to have actively mined, smelted and traded tin between the 11th and 15th centuries AD . Tin deposits exist in many parts of South America, with minor deposits in southern Peru, Colombia, Brazil, and northwestern Argentina, and major deposits of exploitable cassiterite in northern Bolivia. These deposits were exploited as early as 1000 AD in the manufacture of tin bronze by Andean cultures, including the later Inca Empire, which considered tin bronze the "imperial alloy". In North America, the only known exploitable source of tin during ancient times is located in the Zacatecas tin
2519 aluminium alloy 2519 aluminium alloy AA 2519 is an aluminium alloy principally containing copper (5.3–6.4%) as an alloying element. It also contains 0.25% silicon, 0.30% iron, 0.10–0.50% manganese, 0.05–0.40% magnesium, 0.10% zinc, 0.02–0.10% titanium, 0.05–0.15% vanadium, 0.10–0.25% zirconium, 0.40% silicon-iron compounds, and up to 0.15% trace elements. The density of 2519 aluminium is . It was first registered in 1985, in the United States. One application for this alloy is in aircraft armor, where it has equivalent ballistic characteristics to AA 7039, and a reduced susceptibility to stress corrosion cracking as compared to AA 5083. AA 2519-T87 plate is weldable using AA