In conventional mining, prospecting methods are used to increase the degree of certainty with regard to the stock of metals. Similarly, prospecting in terms of "urban mining" aims to increase the information about metal stocks available for recovery in the built environment. Infrastructure systems, such as for power supply and heating, are rich in copper, aluminum and iron (including steel). For a number of reasons, pipes and cables remain in the ground after being taken out of use or disconnected. This is also true for entire obsolete systems. In this paper, these infrastructures "cold spots" are viewed as hibernating stock with a significant potential for urban mining. less thanbrgreater than less thanbrgreater thanThe infrastructure systems for AC and DC power, telecommunication, town gas and district heating in the city of Norrkoping, Sweden, have been quantified and spatially allocated with a GIS-based approach of Material Flow Analysis (MFA). About 20% of the total stock of aluminum and copper in these systems is found to be in hibernation. The findings also indicate that cables have been disconnected to a larger extent than pipes. As an example, cables for DC power, taken out of use in the late 1930s yet still in the ground, consist of 230 tonnes of copper. The results illustrate a clear tendency for larger stocks of hibernating copper and aluminum to be found in the central rather than the outer parts of the city. A reverse, ring-like pattern is true for iron, mostly because the central parts of the town gas pipes are used for fiber optics. less thanbrgreater than less thanbrgreater thanParticular focus has been placed on the industrial area of Sodra Butangen, which is slated for redevelopment and re-zoning from industrial to residential. Since the ground will be dug up for sanitation purposes anyway, the entire metal stock can be taken into prospecting consideration. Analysis shows that the chances of finding aluminum here are 28 times higher than in the rest of the city. less thanbrgreater than less thanbrgreater thanWe argue for an increased MFA focus on the heterogeneous complexity found in the details of the specific locale, rather than striving for generalized assumptions about the broader picture. In doing so, MFA could very well provide a tool for a future business line of urban mining of hibernating metal stocks.

Our societies are reliant on metals to such an extent that the total amounts of some of them in the built environment are comparable in size to the remaining amounts in known mountain ores. Because of concerns about mineral scarcity, the United Nations has assessed alternative sources for metal extraction and targeted urban areas in general and infrastructure systems in particular, since these are large, spatially concentrated and rich in metals. Referring to the possibility of recovering these metal stocks, infrastructure systems constitute what material flow researchers has conceptually termed “urban mines.” While most urban infrastructure is in use, significant amounts of cables and pipes have been disconnected and remain in their subsurface locations; they are “hibernating.” In this article, we analyze the occurrence of such hibernation in the Swedish city of Norrköping's urban infrastructure mine where, we know from a previous study, that every fourth kilo of infrastructure is discarded. Our applied perspective is different from the logic of system expansion as a way to meet increased demand often found in the field of infrastructure studies since we are interested in how systems are disconnected and left behind. This enables us to offer a refined understanding of the concepts of infrastructure “decline” and infrastructure “cold spots.” We argue that to prevent the increase of dormant infrastructures and to engage in the urban mining of already dormant infrastructures, we must develop a sensibility to the materiality of derelict infrastructure components and the underlying causes for why they form different kinds of spatial patterns.