Rock Bolting in Underground Mining: Enhancing Stability & Safety Rock bolting is a critical ground support method in underground mining, designed to reinforce rock masses and prevent failures. The selection of bolt type and installation depends on rock mass quality, assessed using Rock Mass Rating (RMR) and Geological Strength Index (GSI), as well as excavation size and mining method. 🔹 Rock Types & Classification: • Good Rock (RMR: 61-80, GSI: 60-80) – Minimal support required, standard bolting. • Fair Rock (RMR: 41-60, GSI: 40-60) – Systematic bolting with grouted rebar. • Poor Rock (RMR: 21-40, GSI: 20-40) – Reinforced bolting with mesh and shotcrete. • Very Poor Rock (RMR <20, GSI <20) – Cable bolts, shotcrete, and systematic reinforcement. 🔹 Bolt Types & Applications: • Mechanical Bolts (Split Set, Expansion Shell) – Quick support in competent rock. • Resin-Grouted Bolts (Rebar, Dowel) – Strong anchorage for weak rock. • Cable Bolts – Deep anchorage for poor rock conditions and large spans. • Self-Drilling Bolts (SDA) – Ideal for fractured rock, grouted during installation. • Friction Bolts (Swellex, Split Set) – Fast installation for dynamic conditions. • Super Bolts – High-capacity, long bolts (6m+) for deep-seated failures. 🔹 Bolt Dimensions & Spacing: • Diameter: 16mm – 39mm (common sizes: 22mm – 32mm). • Length: 1.2m – 6m (cable bolts may exceed 6m). • Spacing: Typically 1m – 1.5m apart, depending on ground conditions. 🔹 Geotechnical Inspection & Monitoring: • Pull Testing for load verification. • Displacement Monitoring (extensometers, convergence meters). • Ultrasonic & Acoustic Testing for bolt integrity. • Numerical Modeling (FLAC3D, RS2, Map3D) to predict stability. Proper bolt selection, systematic reinforcement, and geotechnical monitoring are key to safe and efficient underground operations. What bolting strategies do you use in your operations?