Mining in the middle of the urban area – this is made possible by urban mining. Demolition of a building, for example, generates a lot of construction waste. These are valuable secondary raw materials, from which, depending on their composition, material for future construction projects can be created. To recover the reusable rubble, all easily accessible and non-toxic components (e.g. plasterboard partitions, suspended ceilings, etc.) are first removed, loaded separately and sent for recycling.
Any necessary decontamination is followed by the demolition, during which valuable materials such as metals (e.g. steel, copper, etc.) are carefully removed and sorted. The mineral masses are separated into mixed fractions of sand-lime bricks, lightweight concrete and concrete. The concrete is crushed and either used as recycled building material on site or in new construction projects. Alternatively, the crushed concrete is transported to concrete plants for the production of new concrete. Wood and glass are recycled and reused, mostly as raw materials for the glass industry or for the production of wood composites.
Three essential aspects are at the centre of this:
- Resource conservation: By reusing materials, the need for new raw materials is reduced, which contributes to the conservation of natural resources.
- Improved CO2 footprint: The production of new building materials is energy-intensive and causes high CO2 emissions. Urban mining reduces energy consumption and thus CO2 emissions.
- Avoiding waste: Demolition materials are recyclable and not waste. The amount of rubbish is significantly reduced and landfill space is conserved.
A practical example
One example in which urban mining played a significant role is the ‘Korbach Town Hall’ project in Korbach. The aim of the urban mining concept was to reuse as much material as possible from the 1970s building in the new building and to save valuable raw materials by means of selective dismantling and subsequent local recycling of the mineral demolition materials. PORR Hochbau West realised this sustainability requirement: the processed demolition materials were used as recycled aggregates when backfilling the foundations, installing the frost protection layer and the in-situ concrete, as well as for the architectural concrete façade made of prefabricated elements.
Sebastian Grimm, Head of the Gütersloh branch of PORR building construction West, is convinced by the concept: ‘PORR is a pioneer in the field of sustainable deconstruction and urban mining. With the “Korbach City Hall” project, it is demonstrating the possibilities that exist in the field of processing and reusing raw materials.’
Urban mining: the basis of the circular economy
Claude Jeutter, Technical Director of PORR in Germany, also draws a positive conclusion: ‘Urban mining offers significant potential for sustainable construction. By reusing and recycling materials from existing buildings and infrastructure, resources are conserved and the amount of waste is significantly reduced. With urban mining, the construction site becomes a mine of raw materials and thus makes a sustainable contribution to achieving the ESG goals.’
In addition, urban mining supports the development of innovative technologies and methods for the efficient use of resources. The integration of urban mining into construction and demolition processes thus plays a key role in more resource-efficient construction methods. This is because it makes a significant contribution to the circular economy. This paves the way for more sustainable construction.
