In his research, Björn Wallsten has explored matter displaced in such processes. He has investigated subsurface infrastructure systems with a particular focus on the cables and pipes that are continuously disconnected and left behind, forming a metal deposit below city streets. These quantities are evidence of society’s persistently wasteful handling of mineral resources. Wallsten terms this largely unknown realm of system rejects the “Urk World”. “Urk” is short for the Swedish term “urkopplad”, meaning “disconnected”, an abbreviation found on old maps denoting abandoned infrastructure parts. Wallsten has scrutinized the Urk World as a geo-social formation: how it emerged as an infrastructural phenomenon, its political relevance, and how it could be recycled with resulting environmental benefits. Suggesting the Urk World as a resource base, Wallsten adheres to urban theorist Jane Jacobs, who argued in the 1960s that cities would be the mines of the future. Since her day, the term “urban mining” has been used in reference to her vision. “The Urk World”, Wallstens doctoral thesis, was the world’s first on this topic.