Subsurface mining is a method used to extract minerals and ores that are located deep underground. There are three main types of subsurface mining:
- Room and Pillar Mining: This method involves creating rooms by cutting into the coal seam and leaving pillars of coal to support the roof. It is commonly used in coal mining.
- Longwall Mining: In this method, a long wall of coal is mined in a single slice. The roof is supported by hydraulic supports, and as the mining progresses, the supports are moved forward. This method is highly efficient and is also used in coal mining.
- Block Caving: This technique is used for mining large ore bodies. It involves undercutting the ore body and allowing it to collapse under its own weight. The broken ore is then extracted from the bottom. This method is typically used for mining large, low-grade ore deposits.
Each of these methods has its own advantages and is chosen based on the type of mineral, the depth of the deposit, and the geological conditions.