Underground mining refers to various techniques used to excavate minerals from beneath the Earths surface. It is commonly used for hard minerals containing metals such as gold, silver, iron, copper, zinc, nickel, tin, lead, and gems like diamonds and rubies. The process involves accessing the ore through declines (ramps), inclined vertical shafts, or adits, and then excavating levels and stopes to access the ore body. There are two principal phases of underground mining: development mining and production mining. Ventilation is a critical aspect of underground hard rock mining to ensure a safe working environment.
The principal means of access to an underground ore body is a vertical opening called a shaft, equipped with elevators for transporting workers, machines, and materials. Another way of gaining access to the underground is through a ramp or a tunnel driven downward from the surface. In the case of underground coal mining, two main methods are practiced: room-and-pillar mining and longwall mining.
Room-and-pillar mining is used for relatively flat or gently dipping coal seams, leaving behind pillars of coal to support the overburden and rock layers above. Longwall mining involves a mechanized coal shearer mounted between a conveyor system and hydraulic roof supports, allowing for almost complete automation of the process.
Underground mining is essential for extracting ore safely, economically, and with minimal waste, especially when ore bodies lie at considerable depths below the surface. It is practical when the ore bodies are large and located farther from the surface, and various methods such as room and pillar mining, narrow vein stoping, and large-scale mechanized mining are used.
In summary, underground mining is a crucial method for extracting valuable minerals and ores from beneath the Earths surface, and it involves various techniques and methods tailored to the specific characteristics of the mineral deposits being mined.
