Emeralds are gem-quality specimens of the beryl mineral family with a rich, distinctly green color. They are found in igneous, metamorphic, and sedimentary rocks in a small number of locations worldwide. For over 5000 years, emeralds have been one of the most desirable and valuable colored gemstones.
For example, the Agway Elevator was built on a concrete mat 3 feet thick which in turn rests on a natural foundation of stiff clay. But whatever the foundation for the elevator was, be it wood pilings or concrete slabs, construction of the elevator itself could begin once the base was completed.
A tunnel called a Ramp typically connects the bottom of the shaft with the rest of the mine, this Ramp often contains the mine's water handling facility, called the Sump, as water will naturally flow to the lowest point in the mine.Shafts may be sunk by conventional drill and blast or mechanised means.f the shaft is used for mine ventilation, a plenum space or casing is incorporated into the collar to ensure the proper flow of air into and out of the mine. Beneath the Collar the part of the shaft which continues into the ground is called the Shaft Barrel.