Quantitative Analysis of Basalt Damage Under Microwave Radiation Utilizing Uniaxial Compression and Nuclear Magnetic Resonance (NMR) Experiments  
[PERSON]  
School of Resources and Safety Engineering, Central South University, Changsha 410017, China  
1  
[PERSON]  
School of Resources and Safety Engineering, Central South University, Changsha 410017, China  
1  
[PERSON]  
School of Resources and Safety Engineering, Central South University, Changsha 410017, China  
1  
[PERSON] and [PERSON]  
School of Resources and Safety Engineering, Central South University, Changsha 410017, China  
1  
Footnote 1: email: {j.liu,j. reduced efficiency [14]. In response, recent advancements in rock-breaking technologies, including high-pressure water jets, microwaves, lasers, and electron beams, have been introduced into mining operations [15; 16; 17; 18; 19]. Among these, microwave irradiation, which can weaken or even destroy rock strength, is considered a promising non-explosive mining method due to its precision, cost-effectiveness, and alignment with green mining principles. The use of microwaves for rock weakening has become a prevalent trend and focus of research in rock-breaking technologies. Researchers have explored the effects of microwave irradiation on rocks by evaluating changes in their physical and mechanical properties post-exposure. [PERSON] [20] reported that the tensile strength of basalt specimens decreased from 12 MPa to 8 MPa when the irradiation duration was increased from 10 to 20 s at a power level of 5 kW. Similarly, [PERSON] [21] demonstrated that when using a multimode cavity microwave device at 15 kW, the point load strength of ore specimens decreased by 55% after just one second of exposure. [PERSON] [22; 23] found that the longitudinal wave velocity in cubic rocks with 20 cm sides decreased by 2.2%, 6.0%, and 8.4% after irradiation times of 5, 10, and 15 min at 3 kW, respectively. [PERSON] et al. [24; 25; 26] studied the effects of microwave irradiation on the mechanical and thermodynamic properties of granite, sandstone, and basalt. Energy-based studies, such as those by [PERSON] [27], [PERSON] [28], and [PERSON] [29], have conducted extensive experiments and simulations demonstrating a significant reduction in the Bond's work index of rocks after microwave treatment. [PERSON] [30] concluded that the energy storage limit and residual elastic energy density of granite are inversely proportional to the power and duration of irradiation. Collectively, these findings highlight that microwave irradiation effectively weakens rock strength. The absorption capacity of minerals within rocks for microwaves is primarily determined by their dielectric constants; minerals with higher dielectric constants absorb microwaves more efficiently, resulting in more rapid temperature increases. Due to the variation in dielectric constants among different minerals in a rock, some minerals heat faster under microwave radiation, while others heat more slowly, creating temperature gradients within the rock. This differential heating, combined with the varying expansion rates of minerals, induces thermal stresses that cause both inter-crystal and intra-crystal fractures, as illustrated in Figure 1. Compared to other rock damage methods, microwave radiation is characterized by two critical parameters: power and duration. Understanding the distinct effects of these parameters on rock deterioration is crucial for the practical application of microwave-assisted rock breaking in mining. [PERSON] et al. [31] reported that higher microwave power and longer irradiation times exacerbate basalt damage, with faster surface temperature increases correlating with reductions in both dynamic compressive strength and longitudinal wave velocity, alongside increases in peak strain. [PERSON] [32; 33] emphasized that a rock's mineral composition significantly affects its sensitivity to microwaves, underscoring the importance of optimizing power and duration settings for effective microwave-assisted rock breaking.