Mining

• The underground mining process begins when workers discover a quantity of a material at least 125 feet beneath the Earth's surface, according to the Illinois Department of Commerce and Economic Opportunity. When materials are discovered 125 feet or closer to the surface, miners use a process called surface mining. Depending on the depth of the material being mined, any number of techniques are employed and include the use of different mine shafts, such as slope, drift and shaft mines.
  
  

Permits

• Within the United States, any individual or organization beginning mining operations must obtain permits from the state governments of the area. Included in the information required is evidence of the environmental impact of facilities built to provide support for the mine. Other information needed for a successful permit application includes the formulation of a subsidence avoidance plan, with the mine owner accepting responsibility for any collapse of land caused by the mine or contamination of water supplies.
  
  

Shafts

• The physical process of underground mining begins by inserting a shaft that allows access to the material to be mined. The shaft grants access to workers and equipment and also allows ventilation of air through the mine. If a mine is close to the surface, a slope shaft is inserted, meaning that a tunnel is created that slopes from the surface to the mine face. A drift shaft is usually created when a seam of material is discovered in the side of a hill or mountain and is often used when a surface mining operation becomes too deep for worker safety. A shaft mine is created by drilling a hole up to 30 feet wide and up to 1,000 feet deep with elevators inserted for the movement of workers and equipment.
  
  

Mining

• Room and pillar mining is a process where around 50 percent of the material is mined from a seam; the remaining material is left to form pillars to provide support for the mine and avoid a collapse, according to the Illinois Department of Natural Resources. A remotely controlled machine that moves back and forth over the mine face to remove material, called a continuous miner, is used in underground coal mining. Longwall is usually completed after the room and pillar process is finished to remove the remaining material. A longwall mining machine with a rotating drum moves through the mine, removing the final material. The machine also protects from collapsing roofs with a hydraulic shield. The material removed from the mine is moved back to surface on conveyor belts and in rail cars where it is taken to a processing plant.