Urban mining

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.

The name was coined in the 1980s by Professor 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.

The term, urban mining, has been expanded in common use to include 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.

From the World Economic Forum, November 22, 2023, "What is urban mining – and why do we need to do more of it?" https://www.weforum.org/agenda/2023/11/urban-mining-circular-economy-ewaste/

"Another strong use case is for waste materials from demolition or construction. Around 850 million tons of construction and demolition waste were created by Europe alone in 2020 – more than a third of all waste generated in the region."

From Metabolic - Merlijn Blok - Updated and rewritten on 28/03/2024 - "From Buildings to Resources: The Role of Urban Mining in Circular Cities" https://www.metabolic.nl/news/urban-mining-and-circular-construction/

"Why do we extract, produce, and transport scarce primary materials from mines around the world, when there are abundant secondary sources throughout our cities?"

Yes, why?

By salvaging and repurposing these materials, urban mining helps reduce the demand for new resources, minimizes waste, and promotes sustainable practices in the construction industry. This practice aims to reduce the need for extracting raw materials from natural resources, minimize waste, and promote sustainability by recycling and repurposing materials found in urban environments. Urban mining of building materials contributes to resource conservation, environmental protection, and the circular economy by extracting value from existing would-be-waste streams.

References

Sources

• Kuroda, Kouichi; Ueda, Mitsuyoshi (2011). "Cell surface design for selective recovery of rare metal ions". In Ike, Michihiko; Yamashita, Mitsuo; Soda, Satoshi (eds.). Handbook of Metal Biotechnology: Applications for Environmental Conservation and Sustainability. CRC Press. ISBN 9789814267991.
• Yu, Jeongsoo; Che, Jia; Omura, Michiaki; Serrona, Kevin Roy B. (2011). "Emerging issues on Urban Mining in Automobile Recycling". In Kumar, Sunil (ed.). Integrated Waste Management. Vol. 2. InTech. ISBN 9789533074474.
• Nakamura, Takashi (2016). "How to recover minor rare metals from e-scrap". In Neelameggham, Neale; Alam, Shafiq; Oosterhof, Harald; Jha, Animesh; Dreisinger, David; Wang, Shijie (eds.). Rare Metal Technology 2015. Minerals, Metals & Materials. Springer. ISBN 9783319481883.

Further reading

• Nakamura, Takashi; Halada, Kohmei (2014). Urban Mining Systems. Briefs in Applied Sciences and Technology. Springer. ISBN 9784431550754.