In the United States, 98 percent of newly discovered coal and valuable metals, such as copper, gold, silver, palladium and iron ore, come from mining. In the past, teams of thousands of men would be sent to extract valuable materials by hand, but now, large machines are used to drill tunnels in which miners can explore and directly extract valuable materials that are embedded in limestone or granite by using a myriad of new machines.
Used in underground mining, longwall machines advance slowly through a tunnel and use enormous sheers to cut mounds of rock, coal and dirt from the wall of the corridor. Next, smaller blades are used to cut the coal from the other materials, and finally, the relatively pure coal is lifted and dropped onto a conveyor belt that takes it out of the mine. Each of these machines can mine 1,000 tons of coal in one day.
These machines use a steel drum that is constantly rotating to loosen coal from the surrounding rock. The drum has a series of teeth that are made of tungsten, which is one of the strongest metals in the world, to rapidly tear apart the formations of granite and limestone.
Finding Precious Metals
Metal detectors will only beep or provide an alert when metal is within 20 feet of the surface. In order to locate precious metals that are hundreds of feet underground, prospectors scan the area by using a long-range detector that will send a powerful signal through the ground.
Like sonar that is used in water, the signals will alert the machine if it comes into contact with any type of metal, and the time the signal takes to bounce back and the direction that it travels will accurately provide the user with the depth of the metal, the size of the ore and its overall shape.
Removing Thousands Of Pounds Of Dirt
Each time a precious metal or coal is newly discovered in an area, the profits of companies in the industry of heavy equipment are raised tremendously. To remove enormous amounts of dirt from mines, miners use hydraulic excavators, skid steer loaders, tractors and hydraulic crushers.
Moving The Materials
Once various metals or pieces of coal are separated from the other materials, conveyor belts that stretch thousands of feet are used to transport them to a storage area.
In the past, miners had to walk through steep, dark and dangerous tunnels to reach the precious metals that they were extracting, but now, tramways carry miners to their destinations above surface mines.
Additionally, intricate railway systems take miners to any location in an underground mine, and sensors are placed every ten feet on the track that will automatically notify the managers of a collapse and stop the train.