Shotcrete, a critical construction technique in mining, refers to concrete or mortar pneumatically projected at high velocity onto surfaces (e.g., tunnel walls, rock faces) using specialized equipment. Its rapid application and adaptability make it indispensable for ground stabilization and safety in underground mining.

   Key Aspects of Shotcrete in Mining:

   1. Application Methods:

   ① Wet-mix: Premixed concrete (including water) is pumped to the nozzle, where compressed air propels it onto surfaces. This method reduces rebound and dust.

   ② Dry-mix: Dry materials are conveyed via air to the nozzle, where water is added. This allows faster adjustments but generates more dust.

   2. Primary Functions:

   ① Ground Support: Stabilizes excavation surfaces by forming a bonded structural layer, preventing rockfalls and controlling deformation.

   ② Dust Suppression: Reduces airborne cement dust during application, though challenges persist in optimizing mixing and spray parameters.

   3. Technological Advancements:

   ① Robotic Systems: Automated spray manipulators improve safety, reduce rebound, and enhance placement accuracy in complex geometries (e.g., curved tunnels).

   ② Fiber Reinforcement: Steel or polypropylene fibers are added to boost tensile strength and crack resistance, especially in high-stress environments.

   4. Environmental and Performance Benefits:

   ① CO₂ Mitigation: Recent innovations integrate bacteria to induce calcium carbonate precipitation, enhancing CO₂ sequestration while improving mechanical properties.

   ② Rapid Strength Development: Achieves early load-bearing capacity, critical for dynamic mining conditions.

   This method has become widely adopted in both hard-rock and soft-rock mining to improve safety and efficiency by providing immediate support to unstable excavated surfaces.