Urban mining

{{Short description|Stockpile of rare metals in discarded equipment}}

An urban mine is the stockpile of rare metals in the discarded waste electrical and electronic equipment (WEEE) of a society.{{sfn|Kuroda|Ueda|2011|p=197}} 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.{{cite book |doi=10.1002/14356007.a12_499 |chapter=Gold, Gold Alloys, and Gold Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Renner |first1=Hermann |last2=Schlamp |first2=Günther |last3=Hollmann |first3=Dieter |last4=Lüschow |first4=Hans Martin |last5=Tews |first5=Peter |last6=Rothaut |first6=Josef |last7=Dermann |first7=Klaus |last8=Knödler |first8=Alfons |last9=Hecht |first9=Christian |last10=Schlott |first10=Martin |last11=Drieselmann |first11=Ralf |last12=Peter |first12=Catrin |last13=Schiele |first13=Rainer |isbn=3527306730 }}

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.{{sfn|Yu|Che|Omura|Serrona|2011|pp=165–166}}{{sfn|Nakamura|2016|p=39}}

File:Agbogbloshie Ghana.jpg urban mine where waste was recycled at the cost of human health{{cite web |title=E-waste in Ghana: where death is the price of living another day |url=https://theecologist.org/2014/aug/07/e-waste-ghana-where-death-price-living-another-day |website=theecologist.org |access-date=5 April 2025 |language=en |date=7 August 2014}}]]

In urban mining, the main motivation is recovery of materials while in "landfill mining" the goal is solving the problem at the disposal level.{{cite journal |last1=Ghisellini |first1=Patrizia |last2=Ncube |first2=Amos |last3=Casazza |first3=Marco |last4=Passaro |first4=Renato |title=Toward circular and socially just urban mining in global societies and cities: Present state and future perspectives |journal=Frontiers in Sustainable Cities |date=30 September 2022 |volume=4 |doi=10.3389/frsc.2022.930061 |doi-access=free |bibcode=2022FrSC....4.0061G |language=English |issn=2624-9634}}

In developing countries, people tend to recycle e-waste at informal sites, including inside homes, without the use of proper equipment and waste management techniques.{{cite web |last1=Reinsch |first1=William Alan |last2=Hokayem |first2=Anthony |title=A Canary in an Urban Mine: Environmental and Economic Impacts of Urban Mining |url=https://www.csis.org/analysis/canary-urban-mine-environmental-and-economic-impacts-urban-mining |access-date=5 April 2025 |language=en |date=29 July 2021}}

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.{{sfn|Yu|Che|Omura|Serrona|2011|p=166}}