What is shotcrete in mining?  Shotcrete is a form of concrete (or mortar) that is pneumatically projected onto surfaces at high velocity. In mining, it’s used to create a protective, quickly applied layer that stabilizes and reinforces rock surfaces. Shotcrete is a critical construction technology in mining and underground operations.

   1. In underground mining, shotcrete is particularly valuable.

   ① Provides Rapid Ground Support: It can be applied immediately after excavation to prevent rock falls, thus enhancing worker safety and allowing faster re-entry into newly opened areas.

   ② Enhances Structural Integrity: When combined with reinforcing fibers (such as steel or synthetic fibers) or mesh, shotcrete increases the ductility and crack resistance of the lining, which is crucial for dealing with the dynamic conditions underground.

   ③ Offers Versatile Application: Its ability to be applied on irregular or complex surfaces without the need for formwork allows it to be used in a variety of mining environments—from hard rock tunnels to shaft linings.

   2. Key Roles in Underground Mining

   Rock reinforcement:

   ①  Seals rock surfaces to prevent weathering and water infiltration, reducing crack propagation.

   ②  Enhances load-bearing capacity by filling gaps and integrating with rock to form stress-resistant structures.

   ③ Safety: Minimizes rockfall risks in fractured zones.

   ④ Sustainability: Innovations like microbial-induced calcium carbonate precipitation (MICP) improve CO₂ sequestration, lowering carbon footprints.

   3. Applications

   ① Deep mining support: Wet-mix shotcrete combined with steel arches and bolts addresses high-pressure, water-rich strata.

   ② Robotic spraying: Automated systems (e.g., PS7I-J robots) enhance efficiency and safety in complex geology.

   Shotcrete can be applied using either a dry-mix (often referred to as gunite) or a wet-mix process, with each method having its own advantages depending on the specific requirements of the mining operation.