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
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