An urban mine is a collection of rare metals found in old electronics that people throw away. Urban mining is the process of recovering these metals using methods like breaking things apart and using chemicals. In 1997, about 20% of the 2,700 tons of gold sold in the market came from recycled gold.

The term "urban mine" was first used in the 1980s by Professor Hideo Nanjyo of the Research Institute of Mineral Dressing and Metallurgy at Tohoku University. This idea became more popular in Japan and other parts of Asia during the 21st century.

In urban mining, the main goal is to recover useful materials. In contrast, landfill mining focuses on solving problems caused by waste disposal.

In developing countries, people often recycle old electronics in informal places, such as at home, without using proper tools or waste management methods.

A study by Japan’s National Institute of Materials Science in 2010 found that about 6,800 tonnes of gold could be recovered from used electronics in Japan.

There is also an international meeting about reusing old electronics to make new devices. The most recent meeting took place from May 21 to May 23, 2025, in Procida, Italy.