Open Collections

Jones, Frances

University of British Columbia

Despite briefly dipping in 2020 during the global Covid-19 pandemic, CO₂ emissions have continued to rise in the 21st century, exacerbating anthropogenic climate change. The most recent climate report from the IPCC states that Carbon Dioxide Removal will be required to keep warming below 1.5 °C. A promising form of CDR is carbon mineralization, which occurs spontaneously in ultramafic mine waste. Continuous monitoring of CO₂ exchange (flux) between the mine waste and the atmosphere was conducted at the closed Cassiar asbestos mine using eddy covariance and dynamic closed chambers. These systems are commonly used in soil science but were used for the first time to measure CO₂ uptake into ultramafic mine waste for the purpose of carbon capture. CO₂ fluxes measured by both systems were found to be highly dependent on temperature and exhibited strong diurnal cycling. Both systems reported fluxes of the same direction and magnitude, but fluxes reported by EC were consistently higher than fluxes reported by DCC. EC was problematic at the site due to consistent data gaps at night; therefore, DCC should be used to calculate long-term flux averages. Manipulation at the site was also effective, with fluxes increasing by 400% compared to the non-manipulated material. Moisture content and surface roughness were two material properties that could be easily manipulated to increase CO₂ uptake into mine tailings. Conventional methods for measuring these properties are difficult to deploy. Short-wave Infrared spectroscopy and photogrammetry were tested to measure moisture content and surface roughness, respectively. Both methods were effectively implemented to measure these properties and their impact on CO₂ uptake. The relationship between surface roughness and CO2 flux was highly linear, but the relationship between moisture content and CO₂ flux was more complex and non-linear. When a screw-drive scroll moved over alkaline waste, CO₂ uptake, moisture content, and surface roughness increased. Results from this work show that with low-cost, low-intervention methods, CO₂ uptake can be increased even at legacy mine sites.

Text

2024-11-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/83289

Geological Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/