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
Sundown Tin and Copper Mine down 7 chains from the mine to the reverberatory furnace. The only building standing besides the furnace was the assay office. Firewood was swung across the creek to the furnace on wire ropes. The copper adit was driven , with winzes and drives off it, and a shaft connecting to the surface from the portal. The most recent smelting of 150 tons of ore produced 25 tons of matte containing 29% copper and 76oz silver and 6 dwt gold per ton matte. Mining recommenced in 1904, but was abandoned again in 1907, this time reputedly due to falling tin prices,