The forgotten mines

Metal prices are rising while large amounts of copper and other
metals lie buried in the ground, forgotten, and of no use. The
concentration is greatest in landfills and under cities. The mines of
the future are now being explored.

Joakim Krook med flera 2012Foto: Peter ModinMetal prices are soaring and even if the supplies of virgin metal are not yet fully exhausted, some metals are becoming a scarce commodity.

“We have been able to mine certain metals from the mines we know of at the moment compared to what is actually remaining, one example is copper”, says Mats Eklund, professor of industrial environmental engineering.

Today scrap copper costs about SEK 60 a kilo, and we know that there are several kilometres of disconnected copper cable buried in the ground, especially in urban areas. The question is at what point it is worthwhile digging it up and reusing it.

Of course there are even larger quantities of steel and iron under the ground, which are also no longer being used, as with many other metals.
Mats Eklund

“The amount of metals present in products and buildings is somehow included in the system, but we easily forget what's in the ground. There is a large discrepancy between how much metal we have mined and the amount we actually use”, says Mats Eklund.

New fields of research

Thoughts about the hidden supplies under the ground have given rise to entirely new fields of research, called Urban mining, whereby the city is used as a mine; there is also Landfill mining, which takes advantage of the metals and other resources that are stored in landfills around Sweden and around the world. Instead of viewing landfills as a problem, we choose to see them as a resource, a mine to draw from.

Of course, this inverted approach produces problems, and researchers have a number of nuts to crack. How much in terms of quantities will we be able to bring up? Where are the sufficiently large concentrations and will it be worthwhile to dig them up? What technology is available to do this?

Which laws and regulations prevent this type of exploration and mining, and what sort of changes would be necessary?

Unused resources

At Linköping University's Division for Environmental Technology and Management, there are four projects currently on the go which aim to find the answers to some of the questions. The projects are financed primarily by Vinnova, Formas and the university, but they also have municipal and industrial partners – such as the municipality of Norrköping, Stena Metall and Tekniska Verken in Linköping.

The director of research is Associate Professor Joakim Krook, the Division for Environmental Technology and Management.

"Common to the projects is that they will identify opportunities and obstacles to extracting natural resources from sources that are completely unused today. We see an increasingly fierce competition for strategically important materials such as metals, and therefore, the results of our research will be all the more interesting,” he says.

Some of the projects have been running for about a year, while others are just ready to start. An initial study in Norrköping found for example that there is at least 650 tons of disconnected copper cable.

Four ongoing projects - Technospheric mining


Director of research Joakim Krook.

Cities as mines, with funding from Vinnova, 2010-12. Will estimate how much metal there may be under the towns and cities and what the technical/economic conditions are like to facilitate the extraction and recycling of the metals. 

Assessment of metal extraction from disconnected networks in cities, a new project with funding from Formas 2012-2014/15. This is a demonstration project in which researchers will conduct a practical analysis of the electricity network in Linköping. 

In collaboration with the municipality of Linköping there is also an opportunity to dig up cables, for example old power cables, in places where excavation will be carried out for other reasons. Different techniques will be tested.

Municipal landfills, an ongoing project with funding from Formas. 2009- 2011/12. In Linköping there are 17 known municipal landfills and in the country almost 6,000, of which about one hundred are in operation. This is all about identifying what is in the repositories, developing methods and evaluating the results.

Ash landfills – a project run in collaboration with Tekniska Verken 2010-13.
Aims to find out how much metal can be found in the ashes from waste incineration, if it can be extracted and if so, by which methods.

17 January 2012

Researchers