A mine entrance is technically an 'adit'
adit
The vertical rows on the periodic table are called groups.The vertical rows are called periods and the horizontal columns are called groups.
Shaft mining or shaft sinking refers to the method of excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom.
The question is a little vague. So i hope i give the answer you were looking for. The vertical portion of the small diameter of the valve is called the stem. The vertical opening distance is called valve lift. The entire length of the valve would be the overall length. Hope this may help?
A mine entrance is technically an 'adit'
Adit
Adit
Adit
An adit. In North America, the horizontal or sloped entrance to a mine is called a "Portal". Portal more specifically refers to the portion of the shaft visible from the outside of the mine. In some areas, the Portal portion of a horizontal shaft is called the "Drift Mouth" or "Drift Portal" as this shaft leads into a "Drift Mine". With a vertical shaft, that portion would be called a "Collar".
The horizontal entrance is called a portal. If there are two portals, then you call the excavation a tunnel. If there is only one, it is call a drift or adit.
A horizontal entrance to a mine is known as an adit.
adit
how are they supposed to mine above ground? mining is defined by making an entrance underground, otherwise it isn't called mining anymore.
A shaft is a hole dug in a mine.
Adit
at the entrance to Merry Vale there is a rich tin vein mine and get garnet there