What is underground mining used for?
Underground mining is used when the mineral deposit lies deep below the surface of the earth. When developing an underground mine, miners first must dig two or more openings, or tunnels, deep into the earth near the place where they believe coal or minerals are located. Depending on where the vein of ore is in relation to the surface, tunnels may be vertical, horizontal, or sloping. One opening allows the miners to move in and out of the mine with their tools and also serves as a path for transporting the mined rock by small railroad cars or by conveyor belts to the surface. The other opening is used for ventilation. Entries are constructed so that miners can get themselves and their equipment to the ore and carry it out, while allowing fresh air to enter the mine. Once dug to the proper depth, a mine’s tunnels interconnect with a network of passageways going in many directions. Long steel bolts and pillars of unmined ore support the roof of the tunnel. Using the room-and-pillar method
