Courtesy of Maria Holuszko

After spending several decades working on mineral processing solutions for the coal mining industry, Maria Holuszko, a professor at the University of British Columbia, is focusing increasingly on finding value in waste. She is a proponent of urban mining – extracting mineral value from consumer waste streams – and is now applying her expertise in mineral processing to the growing resource created by obsolete electronic gadgets, also known as e-waste. At the Urban Mining Innovation Centre, part of the university’s Norman B. Keevil Institute of Mining Engineering, Holuszko hopes to simultaneously improve the economics of recovery from discarded objects and the ecological impact their disposal has in the long term.

CIM: Your background is in much more conventional mining – in coal specifically. What draws you to urban mining now?

Holuszko: When you get older you get this perspective that you’d like to contribute to something bigger. It worries me that we create so much waste and we don’t do much about it. Sometimes when I talk to my students, I tell them I’m not worried that we’re not going to find any new ore deposits – I’m more concerned about how we are going to deal with the waste that we create. I’m optimistic that mining will do well, but our treatment of waste can drastically improve.

I’m still involved with coal but the switch for me has been the transition to recycling and reprocessing of industrial waste. The fact that I’ve worked with coal and mineral processing has helped me to understand how we can actually address those situations. My contribution to research is now focused on the recovery of waste, even for coal mining.

CIM: What does a background in mining bring to the recycling sphere?

Holuszko: I’m treating the waste as an ore body in the way I think about how we process it. For example, in mining we reduce the size of the ore gradually, and for each size there’s a different technology involved. If I apply this to recycling, specifically cellphones, in order to access the gold (which is typically a gold plated layer on some part of the phone) we need to reduce the size of the particles we are treating. The principles of mineral processing have allowed me to understand how to make the process more efficient and automated.

One thing we strive to do is to avoid manual labour because some of the metals in waste, like mercury and lead, are toxic. If we look at this waste stream as a big mine, we move to a more automated and less hazardous environment for the workers.

CIM: How is urban mining different than recycling?

Holuszko: I see recycling as the first step: collecting, dismantling and sorting things. It’s a bit old school, the way we talk about recycling, because we don’t really think about how to do a good job of extraction of each stream coming out of the process. Urban mining is concentrated also on integrated engineering – finding ways we can recover metals that before we didn’t pay much attention to and thinking about this from the very beginning. This type of engineering is also integrated with social and economic values. We don’t want to be those researchers sitting in a lab working on something that turns out not to be useable in the end because it’s uneconomical or some other reason. With electronic waste, the stream is growing exponentially and we are looking to extract the value from this waste stream in a smarter way than conventional recycling.

CIM: Most urban mining is concentrated on e-waste. How big of a waste stream is that now?

Holuszko: It’s about 40 million tonnes a year globally, and in Canada in 2014 we had about 700,000 tonnes. It’s projected we’ll hit 50 million tonnes a year globally by 2018, but this is projected based on the life expectancy of electronic equipment. It’s huge and it’s growing – I’m sure you’ve had many cell phones in your life, and the trend towards replacing them is only increasing.

But this data is only from sales. In urban mining there’s a need for statistical modeling so that we can improve how we project waste streams. There’s no tracking really (after a device is sold), so we still need to work on improving data collection and management as well.

CIM: Are there any manufacturers designing products to be more easily mined?

Holuszko: In Europe there are already some countries where manufacturers consult with processing experts so that devices can be more easily dismantled. Finland and Sweden are already quite advanced in that area. Some of our collaborators at the Finnish Innovation Fund are working with bigger companies like Nokia and Outotec.

I think there’s a lot of discussion going on about it here, but I am not aware of any major projects at an industrial scale in North America.

CIM: What are the most important parts of the e-waste stream, from your processing perspective?

Holuszko: It probably wouldn’t surprise you that, because we’re from mining, we focus on where the gold is. In circuit boards and coatings on circuit boards, we find the easiest low-hanging fruit of high-concentration precious metals. The thing is these are also the most complicated systems. There are a lot of plastic resins and new materials to make cell phones do what they do. So circuit boards are very exciting because they are challenging from a processing point of view and they are also the most valuable.

At the same time we are looking at what we can do with fiberglass, plastic and resin type of materials. It doesn’t present us with great value but from an environmental point of view, finding a use for this kind of thing is [key] because it closes the loop so that we don’t have to worry about disposing of them anywhere.

CIM: What sorts of mineral processing innovations are making a big impact in urban mining right now?

Holuszko: There is a lot to be learned from all different disciplines. Some of the work that one of my students that I co-supervise has done is showing great potential. She worked on a selective oxidation process that basically peels gold off the electronic circuit boards prior to further processing. It uses ammonium persulfate so it is much safer than other traditionally used reagents, but it has only been used on a lab scale. In one way we are lucky because in conventional mineral processing, it takes a really long time to extract the minerals that carry metals in order to obtain precious metals from the original rock. In urban mining we start with pure metals that are part of something else, so the process can be shorter but we need to characterize all the materials and innovate the processes to make the extraction economical and environmentally sustainable.