Microwave-Induced Fracturing for Enhanced Permeability in Hard Rocks: A Novel Approach for In Situ Recovery in Mining

Sahar Kafashi; Lionel Esteban; Andrej Bona; Aleksandar N. Nikoloski

doi:10.3390/min15111210

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Microwave-Induced Fracturing for Enhanced Permeability in Hard Rocks: A Novel Approach for In Situ Recovery in Mining

Journal article

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Microwave-Induced Fracturing for Enhanced Permeability in Hard Rocks: A Novel Approach for In Situ Recovery in Mining

Sahar Kafashi, Lionel Esteban, Andrej Bona and Aleksandar N. Nikoloski

Minerals (Basel), Vol.15(11), 1210

2025

DOI: https://doi.org/10.3390/min15111210

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Abstract

in situ recovery

microwave fracturing

permeability

porosity

sustainable mining

Nuclear Magnetic Resonance (NMR)

P-wave velocity

Microwave fracturing and assisted mechanical breakage offer efficient and cost-effective rock excavation potential. However, these methods have not been well studied or understood for the deployment of in situ recovery (ISR) in mining, which could benefit from microwave-induced cracking to accelerate in situ leaching. This paper reports on investigations into the effects of microwaves on rock transport properties, specifically for in situ recovery applications. The research focused on microwave fragmentation of a synthetic ore with composition and particle size similar to many wet ore-bearing deposits, as well as hard lithium-bearing rock (spodumene) as a natural analogue, to assess changes in porosity and permeability after microwave treatment. The experiments involved exposing samples with varying water content to heating with different microwave energy levels, followed by examining the impact on the induced crack characteristics. All the samples were characterized by a suite of measurements before and after microwave treatment, including scanning electron microscopy (SEM), Nuclear Magnetic Resonance (NMR), nitrogen gas permeameter-porosimeter, and P-wave velocity measurements. The results showed a strong dependence of rock properties after microwave treatment on water content. At high water content (100%), NMR results showed a substantial increase in porosity, by nearly 17% and a dramatic 47-fold rise in permeability, from 0.65 mD to 311 mD. However, the treatment also caused partial melting of the sample, rendering it unsuitable for further testing, including permeability and P-wave velocity. At moderate water content (20%), permeability substantially increased (233–3404%), which was consistent with the observation of multiple cracks in SEM images. These changes led to low P-wave velocity values. This research provides crucial insights into microwave fracturing as a method for in situ recovery in mining.

Details

Title: Microwave-Induced Fracturing for Enhanced Permeability in Hard Rocks: A Novel Approach for In Situ Recovery in Mining
Authors/Creators: Sahar Kafashi - Murdoch University
Lionel Esteban - Commonwealth Scientific and Industrial Research Organisation
Andrej Bona - Curtin University
Aleksandar N. Nikoloski - Murdoch University, Centre for Water, Energy and Waste
Publication Details: Minerals (Basel), Vol.15(11), 1210
Publisher: MDPI
Number of pages: 15
Identifiers: 991005833799507891
Murdoch Affiliation: Harry Butler Institute; Centre for Water, Energy and Waste
Language: English
Resource Type: Journal article

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Collaboration types: Domestic collaboration
Citation topics: 7 Engineering & Materials Science; 7.229 Mineral & Metal Processing; 7.229.1157 Flotation
Web Of Science research areas: Geochemistry & Geophysics; Mineralogy; Mining & Mineral Processing
ESI research areas: Geosciences