The dynamic damage pattern and fine-scale damage characteristics of weathered granite after ore leaching

The strength of weathered rock in rare-earth mine blasting and infiltration enhancement technology is one of the keys to maintaining the stability of rare-earth mines, and the form of its damage is the main influence on the leaching efficiency. So, this study uses the SHPB test system, a scanning electron microscope (SEM), and nuclear magnetic resonance (NMR) to look at the compressive strength, fine features, energy dissipation, and fragmentation distribution of granite specimens with three different levels of weathering after a single impact and damage destruction over 0, 30, and 90 days of leaching. The study results indicate that the leaching in 30 days has a significant impact on the nature of the transition. The leaching action will cause changes in the rock’s pore erosion and cavity filling. As the leaching time increases, the rock’s compressive strength changes in a strong, weak, and strong way. The specimens’ macroscopic damage patterns consisted mainly of crushing damage, partial spalling, and the development of tensile shear cracks. The SEM observed the fine structure of the broken rocks after three leaching times, revealing a transition from a large number of pores, loose material, and fissures to small and few pores, no fissure development, and multiple regional cementations. On the other hand, using NMR, we measured the undamaged dense host rock in different states to determine its porosity and pore distribution. We found that the porosity of the rock decreased after leaching and impacting, exhibiting a slightly compression-dense morphology.