The Intergovernmental Panel on Climate Change states that carbon sequestration, carbon dioxide removal, and negative emissions technologies will likely be needed to limit global warming to 1.5 °C and avoid the most devastating impacts of climate change. Moreover, carbon pricing systems worldwide are providing financial incentives to implement greenhouse gas-cutting technologies. The overarching goal of our research is to elucidate fundamental processes related to CO2 sequestration and management and seek out potential applications. We conduct field studies and laboratory experiments supplemented with geochemical modelling to examine mineral-water-microbe interactions. Our work has made significant advances for better understanding carbonate mineral formation in the critical zone, microbial and enzyme-mediated carbonation, enhanced weathering and bioleaching, and mine waste carbonation at Earth’s surface conditions. We are carrying out many exciting projects and are aiming to launch several others in the next year. If you’re interested in joining the team, please email Dr. Power (firstname.lastname@example.org) about your research interests.
Co2 sequestration within Mine wastes
Mine waste (e.g., tailings) generation is escalating as the demand for resources increases and high-grade ore deposits become scarce. Consequently, the mining industry must develop more secure and cost-effective tailings management practices while improving environmental performance such as reducing GHG emissions. Alkaline, ultramafic and mafic (Mg-rich) mine wastes react spontaneously with atmospheric CO2 to precipitate carbonate minerals, thereby securely storing CO2. We characterize mine wastes and assess their reactivity before moving towards measuring direct air capture and employing strategies to accelerate CO2 sequestration. Currently, we are most active in South Africa where we will be launching pilot projects to assess strategies to accelerate CO2 mineralization within mine wastes from diamond mines.
Current projects: 1) Enhancing CO2 mineralization within mine wastes through tailings management practices, and 2) Assessing reactivity of mine wastes for CO2 mineralization. Graduate theses projects available.
Enhanced weathering is the concept of accelerating natural drawdown of CO2 through mineral weathering, which has helped to regulate atmospheric CO2 over geologic time. Pulverized mineral and rock such as olivine and basalt are spread in terrestrial or marine systems. Mineral surface areas are orders of magnitude greater compared to natural bedrock, which dramatically accelerates weathering rates. For this reason, mine tailings are ideal for studying enhanced weathering as a means of carbon dioxide removal from the atmosphere. Our research is working on measuring and accelerating rates of weathering while assessing biological enhancements.
Current projects: 1) Enhanced weathering for carbon dioxide removal from the atmosphere. Graduate theses projects available.
Natural analogues and Magnesium carbonate mineral formation
Insights into carbon sequestration of ultramafic materials are gained by studying natural analogues such as the ultramafic complex (i.e., peridotite) near Atlin, British Columbia, Canada. Weathering of the Atlin peridotite over millennia has led to substantial deposition of Mg-carbonates within playa environments. Formation of secondary Mg-carbonate is intrinsically linked to the availability of Mg. The Atlin peridotite has been partly altered by aqueous and CO2-bearing hydrothermal fluids to serpentinite and quartz-magnesite (listvenite) rocks prior to the formation of the playas.
Reaction pathways of carbonate formation have recently gained greater attention because of their relevance to permanent storage of CO2 in ex situ carbon mineralization processes and deep geologic storage. The Atlin playas host an array of carbonate minerals, most notably magnesite (MgCO3), which is an ideal sink for CO2 because it is the most stable form of Mg-carbonate. We are exploring mechanisms that lead to the formation of magnesite within the Atlin playas.
Related publications include A Depositional Model for Hydromagnesite-Magnesite Playas, Magnesite Formation in Playa Environments, and Room Temperature Magnesite Precipitation.
Current projects: 1) Mechanisms of magnesite formation and carbonate transformation processes. Graduate theses projects available.
Geobiological approaches to carbon management
Geobiological processes have a profound impact on Earth’s carbon cycle and may be exploited for sequestering CO2. Microbes have contributed extensively to carbonate precipitation within oceans, lakes, springs, caves, and soils over geologic time. We have demonstrated the roles of heterotrophic and phototrophic bacteria in facilitating precipitation of carbonate minerals, a long-term sink for CO2. These processes can be utilized in mining environments. Management and containment of mine tailings represent a considerable cost and risk in mine operations because of the potentially harmful environmental impacts of tailings and the possibility of an accidental release. In addition to sequestering CO2, carbonation of mine wastes has the potential to cement tailings to increase stability, reduce dust and sequester toxic metals. Ongoing research is examining how carbon sequestration can be accelerated by bacteria and how biocementation can improve tailings stability.
Related publications include Biologically Induced Mineralization, Modern Carbonate Microbialites, and Accelerating Mineral Carbonation Using Carbonic Anhydrase.
Current projects: 1) Biocementation of mine tailings for improving stability. Graduate theses projects available.