Do you think the pandemic has brought about a shift in the way mining companies think about innovation?

Most of the changes that mining companies have made have been to cope with the constraints that Covid has imposed, rather than to improve operations. The two things are not disconnected, as the future of the industry depends on moving to more autonomous, continuous, production systems. However, that will take a particular focus to accomplish, and it is still difficult to see how the mining industry will be able to recruit the necessary talent to push this change forward if the job on offer is working 10 hours a day in the dark, underground, on your own. Repetitive tasks that are currently done manually should be done by the equipment itself, and the people managing this technology should be able to work remotely.

If we are going to electrify the economy and tackle climate change, we need to be producing metals at a lower cost to compete with cheap carbon. The only way to do this is through innovation and changing traditional methods that have been in place for years. We still hear, “what you are suggesting is not a pace of change that we are comfortable with,” and herein lies the problem: disruption is not comfortable, but it is required if real progress is to be made. In this sense, the Covid effect is helpful; the momentum of the pre-Covid economy, including mining, made ‘change’ difficult to achieve, and the inertia that Covid has brought about creates the opportunity to make changes happen – if the will is there.

What led CEMI to consider a new approach to the issue of tailings management?

The industry has to recognize that the increasing delay in getting approval for mining projects is almost always related to environmental impact. This is all the general public really cares about. If you have failures in the 21st century that kill nearly 300 people, that is not a perception issue. These facilities at Brumadinho and Samarco had been out of production for many years, and nothing about the nature of these tailings ponds was going to change by simply leaving them there. If you rely on human beings to execute perpetual care and maintenance for decades, if not centuries, eventually mistakes will be made.

If we consider waste management in our own households, 30 years ago everything went to landfill, but in time we have learned to re-use and recycle. The same can be said for many industrial business sectors, but the mining industry has not adopted this kind of waste diversion.

In October 2020, CEMI’s Mine Tailings Consortium completed a proposal to a major mining company on the future of tailings management. What does your proposal hope to achieve?

We were hoping to accomplish two things. Number one, a radically different way to manage tailings, and CEMI’s suggestion is to split the waste stream into two, in what we call the SST process (separation, sequestration and treatment). Secondly, we were looking for a useful way to use the benign tail that is left behind, and once the contaminated material has been recycled or stored, then the benign material can be used for agricultural purposes.

Can you elaborate on how this approach to mine tailings management works?

Approximately only 20% of the material we send to a tailings facility is hazardous. The rest is actually benign and can be easily managed by artificial wetlands – pseudo-natural environments that we can create in any climate. Rather than having one waste stream to the tailings facility, why not focus on separating out all the contaminants from the benign material. The 20% of hazardous material left over will also contain valuable material that can be recycled. A lot of the contaminants are the reagents that come from the flotation process, and these can be recovered and reused. The materials that cannot be reused, such as arsenopyrite, can be sealed in silica to become inert and then stored. The water outflow from the 80% of the tailings which is almost benign is set up in a series of cells, some of which to be treated with bioremediation, and others with faster-acting chemistry to ensure it becomes completely benign.

We have also discovered that some of the benign materials in the waste stream, notably the mafic minerals, have value for the agricultural sector. Using mafic minerals from mine waste to elevate the yield potential of poor or damaged soils in the Amazon, for example, is the kind of integration we want to achieve in the long term.