Mining is an industry that pushes the envelope in engineering, and things get even more extreme when it comes to underground mining. The use of underground mines is necessary for excavating at depths greater than 60 metres (the point where surface mining turns inefficient). How Stuff Works highlighted the wide range of depths that underground mines can reach, from 750 metres for coal mines and over 2 kilometres for uranium mines.
The Mine Cage
Every underground mine has mine shafts, and each has an indispensable function. Ventilation shafts clear the toxic fumes that are by-products of blasting and drilling. Recovery shafts carry the ores from the bottom of the mine to the surface. Access shafts carry personnel and equipment to and from the surface. All shafts have crucial components, one of the most notable are mine cages.
The cage acts as transport for workers, equipment, and supplies. The unit itself is connected by steel wire rope to a hoist and, together, they function much like an elevator in a tall building.
Cages vary widely, just like the mines themselves, but they share some basic characteristics. For example, a unit meant for transporting personnel needs to be covered and fitted with a gate to ensure safety. Other safety features are also included so that a cage (and, by extension, its occupants) will be protected in case of hoist failure.
The most noticeable variation is the volume and number of decks, which depends on the size of equipment they handle and the scale of operations in the mine; a mining cage may have a single, double, or triple deck.
Differences in Mines
Underground mines differ widely depending on what ores they excavate. However, even among mines that extract the same minerals, multiple factors still set them apart from each other. Some examples are the rock hardness in the area, elevation differences, environmental conditions, and local mining regulations. This is precisely why leading manufacturers of cages and other mining equipment, such as Wabi Iron & Steel Corp., specialize in the creation of units and components that fulfill the needs of whatever operation they will be used in.
How Underground Mining Works, How Stuff Works
Underground Mining Transportation Systems, EOLSS