How does underground mining reach deep ore deposits?

Underground mining reaches deep ore deposits by creating specialized access points from the surface, as surface mining becomes economically prohibitive at significant depths. The primary methods for reaching these deposits include:1

• Shafts: These are vertical openings excavated from the surface to depths below the planned mining horizon. They serve as the main conduit for workers, machinery, and materials via elevators called cages, while skips transport the extracted ore to the surface. Shafts are also essential for ventilation and utility lines.23
• Ramps: These are tunnels driven downward from the surface, allowing for the movement of equipment and materials into the mine.2
• Adits: In mountainous terrain, miners may drive horizontal or near-horizontal openings called adits into the side of a ridge or mountain to reach the deposit.24

Once access is established, horizontal openings known as levels are driven toward the ore body. Miners then use various stoping techniques to extract the ore, often relying on gravity for transport in steeply dipping deposits. As mining progresses to extreme depths, engineers must account for intense pressure and potential rock bursts using principles of rock mechanics.21