Urban Mining, Interview 11.12.2025 Prfoject on: https://dontwastemy.energy/2026/01/05/urban-mining-the-city-as-a-mine https://dontwastemy.energy (student projects) https://the-horse.eductaion (The Horse education associationI Jack Richardot (Interviewer, ZH, CH) Daniel Locher (Interviewpartner, AWEL, ZH, CH) Definition of Urban Mining Jack Richardot: How would you define urban mining in your own words? Daniel Locher: By urban mining, we mean searching for raw materials within the urban environment and recovering them — bringing them back into circulation. For example, when a building is dismantled, many of its components can be reused. The difference from traditional mining is that mining extracts raw materials directly from nature. Compared to recycling, urban mining is more holistic. Recycling usually focuses on individual fractions, such as cans, which are collected and reused. Urban mining, on the other hand, looks at the entire urban space as a resource reservoir, not just individual material streams. Commonly Recovered Materials Jack Richardot: Which materials or resources are most commonly recovered through urban mining? Daniel Locher: In terms of volume, construction materials are by far the largest fraction — bricks, concrete, and similar materials. When buildings are dismantled or renovated, very large quantities are generated. In Switzerland, a large share of these materials is already reused. Concrete, for example, is crushed and turned back into new concrete, and bricks can also be reintegrated. Metals are also very important, especially those recovered from incinerator bottom ash or electronic waste. Using modern sorting technologies, metals such as copper can be extracted and reused. Jack Richardot: Could you explain the point about metals again? I lost you briefly. Daniel Locher: In terms of quantity, metals are much smaller compared to mineral construction materials. However, their environmental benefit is very high. Extracting metals like copper usually requires mining, often in countries with problematic environmental and social conditions, sometimes involving the removal of entire mountains. When we recover copper from waste, we achieve a very large environmental benefit. The quantities may be smaller, but the impact is significant. Leading Countries and Companies Jack Richardot: Which countries or regions are leading in urban mining? Daniel Locher: I honestly don’t have a comprehensive global overview. What I can say is that the EU and Switzerland are doing a lot in this area. Japan is also frequently mentioned, especially in the metals sector. But I can’t provide a detailed ranking, and I’m not sure how systematically this is measured internationally. Jack Richardot: Which companies are particularly successful in urban mining? Daniel Locher: I can only speak for Switzerland. For large material volumes, these are often construction companies that specialize in building dismantling and recycling. Many large construction firms now offer these services themselves. Then there are specialized companies for electronic waste. When you return an old phone to a shop or collection point, it ends up at such a company. They aim to separate the devices as efficiently as possible and recover valuable materials. Another important area is slag processing plants. If devices are mistakenly thrown into household waste, the plastic burns during incineration, but the metals remain and can be recovered from the slag. Safety and Environmental Risks Jack Richardot: Isn’t that dangerous, for example because of lithium batteries? Daniel Locher: Yes, it is a problem. Fires occur relatively frequently in such facilities. Where it is known that batteries are present, they can be handled accordingly. The real issue arises when batteries enter the system unnoticed. Overall, however, there are strategies to manage these risks. Environmental Impact of Urban Mining Jack Richardot: How exactly does urban mining help reduce environmental impact? Daniel Locher: There are two main effects. The most important one is what we call the substitution effect: if we recover one kilogram of copper from waste, we don’t need to mine that kilogram from a mountain. This avoids massive environmental damage. The second effect is smaller but still relevant: if materials are not recovered, they ultimately end up as waste on landfills. That requires space, alters the landscape, and can lead to pollution — for example, when metals leach into water. By recovering these materials, we prevent such impacts. Limits and Future Outlook Jack Richardot: How significant is the overall effect? Is urban mining enough? Daniel Locher: The effect is real, but globally we continue to need more and more raw materials. Population growth, more devices, more vehicles, and the transition to electromobility all increase demand. Urban mining is extremely important, but it cannot fully replace primary resource extraction. Jack Richardot: How can we improve the handling of recovered materials? Daniel Locher: Transparency is key. Companies should clearly report what they accept, how they process it, and where it goes — ideally in a way that is traceable internationally. In Switzerland this works relatively well; abroad it becomes more difficult. Without transparency, there is a risk that materials are passed on cheaply and end up being poorly treated or even illegally disposed of. Roles of Government, Industry, and Individuals --------------------------------------------------------------------------- Jack Richardot: What role should governments play compared to the private sector? Daniel Locher: The state should actively promote and regulate urban mining, especially by ensuring transparency and standards, while at the same time allowing innovation. Companies, on the other hand, should develop innovative business models that allow them to be economically successful while delivering environmental benefits. Jack Richardot: What can individuals do? Daniel Locher: The most important thing is proper disposal: phones and batteries should go to collection points, not into household waste. Even better is reuse — if a device still works, it should be repaired, resold, or reused. Electronic devices are particularly resource-intensive. International Perspective Jack Richardot: Where could Switzerland make the biggest difference internationally? Daniel Locher: Waste problems are most severe in poorer countries where resources are lacking. Measures must be designed to work in the long term and be locally anchored. One starting point could be better control of used clothing exports, so they don’t end up in countries that cannot manage them properly. A Successful Project Jack Richardot: Do you know a concrete example of a successful urban mining project? Daniel Locher: Yes — metal recovery from incinerator bottom ash in the Canton of Zurich. For many years, systematic efforts have been made to recover as much metal as possible. The project is very advanced, successful, and scientifically supported through extensive measurement campaigns. Looking Ahead Jack Richardot: How do you think urban mining will develop over the next 10 to 20 years? Daniel Locher: The focus will increasingly shift toward a circular economy. Materials should remain in use as long as possible through repair and reuse before being recycled. Metals, for example, can theoretically be recycled infinitely — aluminum is a good example. In the future, batteries and solar panels will become particularly important. Buildings should also be constructed using materials that can be reused — ideally in modular systems, almost like Lego blocks. At that point, it becomes more about circular economy than classic urban mining, although the concepts are closely related. Closing Jack Richardot: Thank you very much for your time and for the conversation. Daniel Locher: You’re welcome. Jack Richardot: Do you have any questions? Daniel Locher: No, everything is fine for me.