Urban mining

Additionally, at the end-of-life of a building, demolition and disposal have been the established process of removal of buildings and their materials, but recycling of major materials, such as steel and concrete, have become common. Beyond that, there is the burgeoning industry of deconstruction of buildings, which is the careful dismantling of a building for its components and elements, all the resources within that can be reused (which is ideal), or recycled. It is estimated that as much as 95% of a typical American house can be reused or recycled, given access to a variety of means of processing (gypsum board, lumber, etc.) and - importantly - exposure of these materials to willing purchasers.

The name was coined in the 1980s by Hideo Nanjyo of the Research Institute of Mineral Dressing and Metallurgy at Tohoku University and the idea has gained significant traction in Japan (and in other parts of Asia) in the 21st century. Research published by the Japanese government's National Institute of Materials Science in 2010 estimated that there were 6,800 tonnes of gold recoverable from used electronic equipment in Japan.

Originally, an urban mine is the stockpile of rare metals in the discarded waste electrical and electronic equipment (WEEE) of a society. Urban mining is the process of recovering these rare metals through mechanical and chemical treatments. In 1997, recycled gold accounted for approximately 20% of the 2700 tons of gold supplied to the market.