Urban mining - prospecting for metals in the invisible city

Abstract

In theory, ‘urban mining’ has a huge potential for enabling more efficient resource use and offering new business opportunities for the cleantech and recycling industries. This concept involves recovering technospheric stocks of previously employed natural resources that have been taken out of use without being collected for waste management. Such hibernating material stocks can be found in old water supply, sewage and power distribution networks – urban structures rich in for example iron and copper. This paper aims to analyze the potential for urban mining of the metals copper and aluminum from hibernating power and communication cables in Sweden. Emphasis is on the economic feasibility of two different approaches for realizing such initiatives. The results indicate that separate extraction of obsolete cables situated below ground in a city is not yet likely to be economically justified for power grid managers. Even in case of integrated recovery during other maintenance work on the grids, additional project costs often exceed potential revenues for the cables. In rural areas, however, both separate and integrated recovery of hibernating cables seem straightforwardly profitable, especially for obsolete copper cables belonging to the regional communication network. It is concluded however that the viability of urban mining is not only a matter of economics. Research aiming to analyze technical, economic, environmental and other institutional conditions for realization of urban mining is therefore strongly encouraged.