Speaker
Description
〖Gideon Osei Faaho〗^1,〖Alex Reinhart〗^2,〖Mehrdad Razahvi〗^1,〖Nicole Hurtig〗^2,〖Jason Simmons〗^3,
〖Laura Waters〗^2,〖Sai Wang〗^3
(1) Mineral Engineering Department, New Mexico Tech, USA.
(2) Earth and Environmental Science Department, New Mexico Tech, USA.
(3) Petroleum Recovery Research Center, New Mexico Tech, USA.
Email: gideonoseifaaho@gmail.com
Abstract
Mineral carbonation is a promising method for permanent CO₂ removal, with carbon mineralization of mafic rocks being one candidate method. In this study, we examine the potential of basaltic mine waste, a material often ignored in mining settings, as a low-cost, geochemically suitable resource for sustainable carbon storage. The issue addressed here is the limited understanding of how basaltic waste heaps mechanically and hydraulically behave when exposed to CO₂-rich fluids during mineral carbonation operations. The basaltic mine waste investigated in this study originates from mining operations associated with copper porphyry mines in western New Mexico and eastern Arizona.
Basalt mine-waste is reactive because it is rich in mafic (“calcium-, magnesium-, and iron-bearing”) silicate minerals. This reactive and presence of divalent cations that react with carbonate ions makes it a favorable medium for both in situ and ex situ mineral carbonation. However, its use would require more information on its aggregate geotechnical stability, hydraulic behavior, and hydromechanical feedback from chemical alteration occurring carbonation.
Despite global interest in carbon mineralization, few studies offer an integrated assessment of the hydro-chemo-mechanical processes governing these reactive heaps, creating a gap in design, safety, and long-term performance considerations. This research aims to determine whether basaltic mine waste heaps can safely and effectively sequester CO₂ while maintaining geotechnical stability and adequate hydraulic conductivity for reactive flow. Specifically, the work assesses (1) baseline material properties, (2) strength and deformation before and after carbonation, (3) hydraulic and leaching efficiency under CO₂-enriched conditions, and (4) numerical modeling of coupled processes that influence slope stability. The methodology combines laboratory characterization, mechanical and hydraulic testing, carbonation column experiments, and finite-element modeling.
The experimental plan includes measurements of density, porosity, particle-size distribution, shear strength, and permeability of reacted and non-reacted basaltic mine-waste aggregate. Reacted aggregate samples were obtained from batch reactor and flow-through carbonation experiments conducted as part of the reactive geochemical testing framework. Strength parameters, including effective cohesion and effective friction angle, together with the bulk Young’s modulus (E), representing the aggregate-scale stiffness of the waste material rather than intrinsic mineral grain stiffness, were measured under varying densities, particle-size distributions, and degrees of saturation to represent realistic heap conditions. Coupling with chemical reactivity was evaluated by integrating results from prior geochemical experiments. Additionally, the viability of these reactive mine-waste aggregates for mine-scale applications was assessed.
Overall, this study aims to better understand how basaltic mine waste can be engineered as a safe, effective, and economical solution for carbon sequestration. In future work, we plan to recommend slope design limits, optimal hydraulic conditions, and carbonation strategies to support large-scale implementation of this emerging CCUS approach.
| References | Atkinson and Meredith (1987); Eppes & Keanini (2017). |
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| Country | United States of America |
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