Beneath our cities are millions of tons of unused and forgotten cables and pipes. In Sweden alone, aluminium, copper and lead are worth billions of kronor. Urban mining – the city’s metal storage facility – is based on society as a resource base where materials collected over time form a metal storage facility that can be used via reuse or recycling.
Metals go dormant when systems are taken out of service and replaced by new ones, without the value of these metals being harnessed. This applies to, as an example, systems for city gas and direct current. Metals also go into dormancy during ongoing maintenance and repairs, or in urban construction projects when entire zones of infrastructure are disconnected. The cables are left in the ground because it becomes too expensive to dig up and take advantage of them.
Over time, materials accumulate in buildings, technical systems, fortifications, urban sediments, and more. They constitute a material storage facility that can be reused or recycled. Most of these materials are used, but there are also large quantities of materials that have been taken out of use and are not reused or recycled. Infrastructure, buildings and technical machinery/equipment and appliances are the major metal stores in our society, where infrastructure accounts for 28 percent of copper use in Sweden.
Aluminium, copper and iron or steel are the most common metals in the pipeline-borne, ground-based infrastructure. Every year, one-sixth of the cables built into the Swedish electricity and telecommunications networks are recycled.
Last reviewed 2022-06-17