The city as goldmine of both materials and knowledge

What’s wrong?

Today, production and consumption of goods in all corners around the world is more extensive than any time before.1 The problem is that our global economy has always been a linear system. We extract raw materials, transform it into something useable and then, after a relatively short lifetime, turn it into waste. But what if I told you that we no longer have to extract raw materials from Mother Earth and have the opportunity to turn our waste into a resource? Intrigued yet?

That sounds better!

Fortunately, businesses are innovating a new industrial paradigm: closing loops. The driving force behind this? Our economy is approaching a tipping point where the old take-make-waste business model is a dead end. Finished, finito and no longer lucrative. Businesses are forced to rethink their products, as the global population is growing and urbanizing and resources are not infinite.

What do cities have to do with this?

Taking into account that cities accommodate a vast amount of the people that design, create and use these products that are eventually thrown away, I argue that cities cover a great part of the solution to make these products available for reuse. Half a century ago, urbanist Jane Jacobs already exclaimed that “cities are the mines of the future”. This approach of urban mining is seen as a way to recycle metals from city waste like buildings, infrastructure and devices.2 The resource stock that has been mined from underground into the human society now has a chance of circularity. Let’s see what’s in this for Leiden!

“As a city of knowledge and innovation, Leiden should be a frontrunner when it comes to sustainability” – Leiden Duurzaam 2030

Abuse the city’s students!

Life in Leiden is highly influenced by the relatively large number of students, as most of them live and study in de city.3 I have always believed that students can offer great help in society’s contemporary problems when it’s in their field of expertise. Because, as cheesy as it may sound, today’s students are tomorrow’s future. And other than that, it is both cost effective and awesome for municipalities or companies to collaborate with a university or a particular group of students.  When you ask students to get the job done you don’t have to hire an over-priced consultant and you are guaranteed that quality will be delivered, as these students will be advised by the country’s best-educated people: their professors.

Can you get back to the point?

Linking the latter story to urban mining in Leiden, there are a couple of things that can be done. Since students are the future’s leaders, scientists, inventors, entrepreneurs and engineers, it’s clever to get them to work together from a systems perspective. We are still counting on technological advancements, pollution-control technologies and public awareness when it comes to determining what forms of urban stocks exist, when these urban stocks will become available for reuse and how these can be reused.

N.B. I would like to remind the municipality and/or companies not to forget to reward these students with an excessive amount of ECTS.


1 J. Li (2015) Wastes Could be Resources and Cities Could be Mines. 

2 P. Brunner (2011) Urban Mining A Contribution to Reindustrializing the City.



10 thoughts on “The city as goldmine of both materials and knowledge”

  1. Nice blog! Interesting idea to involve students in this urban mining. You talk about students getting the job (on urban mining) done. What kind of projects or researches would you have in mind for students to perform to get this urban mining idea rolling?


    1. Hi Wiljo, thank you for your comment. The thing with urban mining is that the concept is relatively new. And the thing about new concepts is that they are open to interpretation and all kinds of research is still to be done (that is what I mean with my last sentence). Because urban mining is so broad, I find it difficult to give you a very specific answer. However, I think awareness is a major step towards urban mining. Tell the citizens that their electronic waste is worth some money! Did you know it is estimated that in the Netherlands over 3 million phones are uselessly lying around in drawers? These phones are still very valuable because they contain – amongst others – rare metals like gold, silver and copper.


  2. Very nice blog to read, and incorporating students sounds like a great idea. I’m also wondering, like @wiljot, what kind of projects would be executed?
    Furthermore, I’m also kinda worried about the continuity of the supply of the urban mining: since metals have a certain life span (and you don’t want to end this any sooner than that exact life span, because that also wouldn’t be sustainable), you can not always mine these materials at the time you need them. What could be a solution for this problem? I can think of incorporating other recycled metal (for example from washing machines, cars etc.), but this probably won’t have the same characteristics as the metals used in buildings. How can this time lag between demand and supply be prevented?


    1. Maybe you can use the data you collect on urban mining for making plans on new buildings. When you know that a certain building containing a certain amount of steel will become available in 10 years, you can take that into account when planning the construction of a new building.


    2. Fenna, thanks for the compliment!
      You have a very good point. Of course we don’t want to extract the valuable metals out of a phone that is still working and best case scenario is that we would never have to demolish another building because they are all future-proof.
      Fact is that urban mining can’t replace the total demand of metals because of two reasons. One; it is often not economically attractive to extract all metals from a product. This can be solved through for instance subsidies and legislation. Two; the demand of metals keeps rising and with recycling you will always lag behind. But hey, something is always better than nothing!


  3. The idea is really great, and i totally see it happen in the near future. The only problem i have with it, other than the quality of the recycled materials, is that there is never enough. You say that we don’t have to mine the earth anymore, but i don’t see how that’s possible. For instance the number of people will continue to rise, so more and more buildings and products are needed. Also for solar panels and windmills large amounts of metals are needed. Is it possible that the mining industry will never get fully circular?


    1. Hey Kevin, you are right. I should probably stop exaggerating, even when I’m pretty enthusiastic about something. The only way the mining industry will become fully circular is because of either legislation and/or innovation. Please see what I wrote to Fenna about it, too!


  4. It sounds good your idea. However, I am uncertain if it is really a great idea.

    According to your idea, students work on their own field of expertise. This will lead (in my opinion) to kind of’ tunnel vision’. Multidisciplinary groups (like our minor Sustainable Development) will bring out of the box ideas. The cooperation between the different sciences (α, β and γ) is excellent, some scientist sees the problems while other have the solutions.
    The best-educated people, the professors will be advisor of students. In my experience, this is almost impossible. The professors of my study are assisted by older students and PhD-students. These students advise the younger students, otherwise the amount of work will be too high for the professors.
    Students have a lot of knowledge, but is this comparable with the knowledge of consultancy? The quality of a professional consultancy is much higher. I think it will be great to drag students into companies, but the students will gain more knowledge than the companies (maybe expected of graduation) which is more in interest for students.

    I think recycling in an urban will be fine. The city Leiden is a city of knowledge and innovation (which you quoted). What is the best way for recycling? Is cradle to cradle potential?


    1. Hi Noortje, thank you for a comment that is almost as long as my blogpost ;). First of all, I feel like you misinterpreted my statement on students working in their field of expertise. Of course I meant sustainability as the field, combined with an interdisciplinary systems approach. This suggests that a transition towards a sustainable way of life means cutting loose from the search for simple solutions and adopting a systems perspective in which both problems and solutions are multi-dimensional.

      Secondly, I’m sorry the professors of your study claim to be too busy for you. In my personal experience, the professors of my study actually love to see their students. They are always eager to give advice when a student is asking for it and love to hear things like “I was trying some of the stuff you taught us, and I hit a snag at the point of […]”. Vice versa I have seen (and been part of) cases where professors benefit from students’ researches for their own research.

      I’m a big fan of C2C because it is an economic, industrial and social framework that seeks to create systems that are not only efficient but also essentially waste free. Urban mining actually goes beyond recycling, because the approach forces you to look at the city as a mine like a miner looks at the natural environment.


  5. I may be a little bit too conservative: but there is a world to win as it comes to students. I really like the idea of urban mining and I think it would be useful in the future. Maybe not to replace the mining that is happening now, but i think we can reduce a certain amount by urban mining in the future. Next to that I think there is a world to win when it comes to divide the waste students produce in the beginning. I think creating awareness about urban mining and dividing waste is a great opportunity!


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