Germany’s increasing shortage of natural resources and the corresponding mounting cost of extracting raw materials signals the need for alternative and innovative ways of collecting and recycling secondary raw materials.

One promising method of securing potential secondary raw materials is “urban mining”, which aims primarily at reclaiming raw materials in urban areas through the reuse of the materials and resources contained in disused products and buildings. Countries with a high demand for resources, but with limited natural resources of their own, can potentially benefit from urban mining.

The German Federal Environment Agency (Umweltbundesamt) recently published a comprehensive briefing titled “Urban Mining”. The briefing highlights the fact that while Germany is a large consumer of raw materials, it is also heavily dependent on imports of major industrial materials, a situation that generates economic and/or political dependencies, strong price fluctuations, and questionable environmental and social standards (such as inhumane mining conditions).

The briefing emphasizes that urban mining is more than just enhanced municipal waste management, but that it has the potential to put the entire stock of long-lived goods — including consumer products, buildings, and landfills — into service, and can provide long-term strategies for sophisticated material flow management.

An estimated 50 billion tonnes of valuable materials are available in Germany’s anthropogenic stock, and this figure is increasing annually. In light of the growing global competition for scarce natural resources, tapping into these anthropogenic resources may help countries with decreasing natural resources to conserve existing natural resources and to secure the life support systems of future generations.

Moreover, aside from numerous future technologies requiring valuable and special metals critical in supply — such as cobalt, silver, neodymium, and platinum — urban mining in Germany could present economic advantages, particularly as it will enable the country to continue leading the way in innovative recycling and may present employment opportunities.

According to the German Federal Environment Agency, major potential lies in the soil, rock, cement, and gravel that is contained in the buildings or scrap metal disposed to landfills. However, the greatest financial value lies in disused metals, which may be obtained from iron girders, steel reinforcements, or copper wiring in empty building or bridges, or in the steel tracks of former railway lines.

The German Federal Environment Agency considers the following areas to have particular potential:

• Recycled rock: Described as valuable, quality-assured secondary building materials which could be manufactured from disposed and recycled construction debris, to the extent that recovery, processing, treatment, and reuse are part of an integrated approach.
• Waste of Electrical and Electronic Equipment (WEEE): Furthermore, a more effective recovery of valuable and special metals from consumer goods, such as electrical and electronic devices, may on the one hand reduce the high dependence on costly imports, and on the other hand help to diminish inhumane working conditions for the handling of WEEE worldwide.
• Material Register: In order to increase knowledge about the occurrence of secondary raw materials, the German Federal Environment Agency proposes a “material pass” for new buildings and consumer products that could enable improved recycling. The material pass is particularly relevant to complex composites, which require sophisticated sorting, separation, and recycling technologies. The stock of materials which lies dormant in certain deposits could then be exploited through active collection and registration of the materials they contain.

Urban mining clearly has huge global potential, the exploitation of which depends on entirely new assessment schemes, innovative models, data bases, improved recycling technologies, as well as an incentivizing legal framework. How this potential develops remains unclear, but industry stakeholders will watch progress with avid interest.