Urban mining is increasingly being taken seriously by industry because it gives access to materials that are buried in waste tips and landfills. However, there is a new kid on the block - literally. Concrete buildings, when demolished, can serve as an excellent source of new building materials. "Instead of transporting aggregates from far away, we can use local buildings as a source for aggregates," says Francesco Di Maio, a researcher in waste separation and recycling technology at the Technical University of Delft in the Netherlands.