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
Antimicrobial copper-alloy touch surfaces products in accordance with the U.S. E.P.A registrations. Products offered by the approved companies include sinks, computer keyboards, faucets, IV poles, tables, stretcher rails, railings, hampers, decorative and architectural hardware (levers, grips, knobs, pulls, towel bars, grab bars, kick plates, bath accessories, outlet covers, light switch covers), laboratory incubators, cabinet hardware, decorative tile, and free weights. The U.S. E.P.A. oversees a stewardship plan to promote the responsible use of Antimicrobial Copper. Further information about the making accurate claims about Antimicrobial Copper is also available. Many antimicrobial copper alloy products have been approved for registration in healthcare facilities, public and commercial