Carbon Mineralization and Critical Mineral Resource Evaluation Pathways for Mafic–Ultramafic Assets

Locating and developing ideal sites for large-scale capture and storage of carbon dioxide has become increasingly necessary due to increasing global emissions and warming. Mafic–ultramafic rocks present a unique geologic setting as they can trap injected CO₂ in pore space, mineralize that CO₂ to permanently store it as carbonate minerals, and simultaneously release critical minerals. However, these reservoirs are undercharacterized relative to sedimentary carbon storage settings. In this study, we execute a methodology for determining carbonation and critical mineral recovery potential in mafic–ultramafic reservoirs. Using an olivine-rich basalt from the island of Hawai’i, we performed petrologic and geochemical analyses to determine its chemistry, mineralogy, and pore network architecture. We use this data to first quantify the nonreactive storage resource potential and determine the bulk storage of 50 MMT of CO₂ in the pore space of a basalt volume test case, along with realistic P10, P50, and P90 scenarios for that same volume. Then, using the chemistry and mineralogy, we both estimate the total mineralization and critical mineral recovery potential, as well as more realistic values based on dissolution–precipitation reactions at the surface areas of pores. This storage resource estimate methodology can assist in accelerating the global commercialization of geologic carbon storage and critical mineral recovery.