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.

Material flow analysis (MFA) has been an effective tool to identify the scale of physical activity, the allocation of materials across economic sectors for different purposes, and to identify inefficiencies in production systems or in urban contexts. However, MFA relies on ignoring the social drivers of those flows to be able to perform its calculations. In many cases therefore, it remains detached from the processes (e.g., urban) that underpin them. This becomes a problem when the purpose of research is to inform the design of detailed recycling schemes, for which micro-level practice knowledge on how material flows are mediated by human agency is needed. The aim of this article is to demonstrate how a particular social science approach, namely, infrastructure studies (IS), can be combined with MFA to enhance the latters potential as a decision support tool. To achieve a successful combination between IS and MFA, the object of inquiry must be carefully defined to function as a boundary object, which allows academic approaches to work together without the need for consensus. This approach is illustrated with a case study example in urban mining research that assesses the hibernating stock of subsurface urban infrastructure in Norrkoping, Sweden. It provides an example of how a well-calibrated MFA and a complementary social science approach can provide hands-on advice for private as well as public actors in a local and place-specific context. The article aims to advance the integration of social science and the study of the physical economy to contribute to the emerging field of social industrial ecology.

This article investigates “urks”, i.e., disconnected parts of urban infrastructure that remain in their subsurface location. The reason for engaging in this topic is resource scarcity concerns, as urks contain large amounts of copper and aluminum that could be “mined” for the benefit of the environment.

Our starting point is that there is a certain non–stagnant capacity of waste–like entities such as urks and that their resistance to categorization is crucial to encapsulate their political potential (cf. Hawkins, 2006; Moore, 2012; Hird, 2013). We investigate how this indeterminate capacity has implications in terms of where future trajectories for urk recovery are conceivable.

The study is based on interviews with respondents from the infrastructure and waste sectors in Sweden. By stressing the relationship between urks and their geo–social subsurface surroundings, we use the respondents’ exploratory interpretations of urks to outline a spectrum of issues that should be further discussed for urks to become a matter of concern. The negotiation of these issues, we suggest, can be conceived of as a form of navigation along the perceived fault lines between actors and priorities, and they must be resolved for increased urk recovery to occur.

In this article, we suggest a methodology that combines geographic information systems (GIS) and material flow analysis (MFA) into a secondary reserve-prospecting tool. The approach is two-phased and couples spatially informed size estimates of urban metal stocks (phase 1) to the equally spatially contingent efforts required to extract them (phase 2). Too often, even the most advanced MFA assessments stop at the first of these two phases, meaning that essential information needed to facilitate resource recovery, i.e., urban mining, is missing from their results. To take MFA one step further, our approach is characterized by a high resolution that connects the analysis of the stock to the social practices that arrange material flows in the city, thereby enabling an assessment of the economic conditions for secondary resource recovery.

To exemplify, we provide a case study of the hibernation stock of copper found in disconnected power cables in Linköping, Sweden. Since 1970, 123 tonnes of copper or ≈1 kg per person have accumulated underneath the city, predominantly in old, central parts of the city and industrial areas. While shorter cables are more numerous than long ones, the longer ones contribute to a larger share of the stock weight. Resource recovery in specific projects reliant on digging comes at great costs, but integrating it as an added value to ordinary maintenance operations render eight locations and 2.2 tonnes of copper (2% of the stock) profitable to extract. Compared to the budget sizes of regular maintenance projects, the integrated recovery of a significant share of the stock comes with relatively small economic losses. Therefore, we suggest integrated resource recovery and regular maintenance as an interesting environmental measure for any infrastructure provider to engage with.