#9 Dr. Greg Dipple, University of British Columbia

January 30, 2018

When it comes to climate change, the mining industry is typically seen as a ‘bad guy,’ depleting the Earth’s natural resources and emitting CO2 in the process. So you might be astounded to learn that carbon can actually be captured and stored using the waste produced in the mining process. In fact, mines could take advantage of this practice, with simple changes in facility design, to become greenhouse gas neutral. Indeed the potential exists for scaling up this carbon capture process to remove billions of tons of CO2 per year—simply by recycling mining waste.  

Ross and Christophe are joined by Dr. Greg Dipple, a professor in the Department of Earth, Ocean, and Atmospheric Sciences at the University of British Columbia. He is a geologist who studies the processes of and driving forces behind mineral reactions with a focus on fluid-rock interactions. In the last 15 years, Dr. Dipple’s research has focused on carbon sequestration at and near the surface of the Earth.  

Dr. Dipple joins Ross and Christophe to explain the process of capturing carbon with mining waste known as tailing. He explains the relative ease with which mines could be redesigned to support the process and the economic and reputational value in removing carbon through mine tailing. Dr. Dipple walks us through his back-of-the-envelope calculations that indicate a very promising $10-20 per ton carbon cost for mine tailing as well as the potential to scale this carbon capture process. We cover several other safety and environmental concerns associated with mining, and Dr. Dipple shares the significance of his partnership with mining companies in deploying his approach in the field. Listen in and learn how Dr. Dipple came to discover the potential for recycling mine tailing to capture carbon.

Resources

Offsetting of CO2 emissions by air capture in mine tailings at the Mount Keith Nickel Mine, Western Australia: Rates, controls and prospects for carbon neutral mining

Dr. Dipple’s Research Articles

“Assessing the Carbon Sequestration Potential of Magnesium Oxychloride Cement Building Materials” by Ian M. Power, Gregory M. Dipple and Peter S. Francis

Key Takeaways

[1:12] The process of capturing carbon with mining waste

  • Identify mines hosted in ultramafic rock
  • Reactive waste product can absorb CO2

[2:47] The nature of the mining industry

  • Conservative, long-term investment
  • Slow to adopt new technology, avoid risk

[3:32] The value of carbon capture for mining industry

  • Reputational AND financial
  • Stabilizes waste, mitigates dust

[5:55] The fundamentals of carbon removal via mine tailing

  • Less than 1% of mined rock = metal/diamond
  • Rest of processed rock is waste known as tailings
  • Tailings much more reactive because finely ground

[7:32] How mines could be redesigned to promote carbon capture

  • Maximize potential for reaction between CO2 and tailings material
  • Safer, more energy efficient and less expensive

[10:33] The affordability of using tailings for carbon capture

  • No new technology involved
  • Billions of tons of highly reactive rock at surface
  • Could offset all CO2 emissions associated with mining
  • Back of envelope calculations = $10-$20/ton

[13:44] Dr. Dipple’s eureka moment re: tailings and carbon capture

  • Working with colleague in Quebec, mid-1990’s
  • Found carbonate minerals in tailings cementing grains of ground-up material together
  • Studied rate of reactions, realized only limited by availability of CO2
  • Understood could provide CO2 rather than increase reactivity

[16:57] The safety concerns associated with toxic waste

  • Increase reaction rates by moving air, make tailings more accessible to gas flow
  • Use onsite power plants as point source of CO2, air capture
  • Could make mine greenhouse gas neutral

[20:00] The potential to scale the carbon capture process in mining

  • Large mine produces 20M tons of rock/year
  • Also generates just under 1M tons of CO2/year
  • Capacity of waste to capture CO2 = 10X greater than emissions
  • Greenhouse gas neutral with just 5-10% of filings (easily extracted)
  • Carbonating all current waste = 200M tons/year
  • Opening new mines based on potential = billions of tons of CO2 removed/year

[26:54] How CO2 might neutralize asbestos 

  • Idea to make asbestos non-toxic by modifying surface properties through process that also sequesters carbon
  • Could destroy asbestos fibers, but would be expensive ($200/ton)

[30:00] The other environmental considerations around mining

  • Water use, impact in sensitive environments (i.e.: Canadian Arctic)

[34:29] Dr. Dipple’s take on next steps for his work

  • Change in carbon economy allows to take lab models to field
  • Pick best sites so that large-scale attempts are successful
  • Ability to deal with carbon now seen as huge value prop for mining companies 

[37:46] How to measure carbon captured through tailings

  • Rigorous scientific approach uses X-ray diffraction technique, three-isotope system
  • Developing methods to get same numbers in realistic time frame at reasonable cost