Urban mining

Urban mining is the recovery of building materials from buildings. This means that materials can be removed from a building in various stages from the point it is deemed that the building is to be removed at end-of-life, or renovated, retrofitted, or remodeled. Without affecting the major structure, equipment, fixtures, furnishings, finishes, and even non-structural components, like windows, doors, and divider walls, can be removed, when permitted, for their value in reuse or recycling or upcycling as raw materials into new products.

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.