Underground mining

e-mail: oshubkina@gmail.comTwitter: @OlgaShubkina

Olga ShubkinaSiberian Federal University

Underground mining is done when the rocks, minerals, or gemstones are too far underground to get out with surface mining. 

Some kinds of underground mining are:

Borehole Mining Drift Mining

Hard Rock Mining Shaft Mining Slope Mining

Borehole Mining

It can be used in open pit mining which is a kind of surface mining.  With borehole mining: a hole is drilled deep enough into the ground to reach whatever is going to be mined; a long, tube-like tool is dropped into the hole; this tube has places for water to be forced down the tube and places where the water can be pushed back up the tube; the water is forced down this tube; the stream of water breaks up the dirt and rock when it hits it; the water combines with the dirt, rock, and minerals to make a combination called a slurry; the slurry is pumped back up to the surface where it is put into a storage tank; the water is drained and the ore is taken out of it; from that time on, the ore is treated depending on what it will be used for.

Borehole Mining technologies

Drift Mining

This kind of mining is done when the rock or mineral is on the side of a mountain.  This makes it an easy, cheaper way to mine. Whenever possible, the opening to the mine will be dug a little lower than the rock or mineral vein.  This makes it easier to get the materials out because gravity helps move them downhill.  The tunnels that are dug are horizontal and are called drifts.Drift mining was really dangerous in the early days.  Many tunnels caved in trapping and killing miners. Ore was often mined this way.  Ore is rock with minerals inside of it. 

Drift Mining

Hard Rock Mining

Hard rock mining is a kind of underground mining.  With this kind, an opening is made that is called an adit. Tunnels into the ground are dug, blasted with dynamite, or drilled out.  These tunnels are called shafts.  Shafts are dug straight down vertically into the ground.  Each shaft has a purpose.  One shaft might be for miners to use to go in and out of the mine.  One shaft might be just for mine machinery.  Another shaft is used for air or ventilation.

The tunnels in a hard rock mine are divided into rooms with rock pillars.

Hard rock mining is one of the most dangerous kinds of mining: it can be very deep underground; some mines like coal ones have deadly gases in them.

Hard Rock Mining

Shaft mining

The shaft mine has a vertical manshaft, a tunnel where the men travel up and down in an elevator.  Equipment is taken into the mine using this shaft, too.   Short tunnels to the ore are dug from that manshaft.  When the ore is dynamited and broken into chunks, it is taken to the top and loaded into trucks through a second shaft. There is usually an airshaft that gives the mine ventilation. 

Slope mines

With slope mining, the coal or mineral bed is located very deep and parallel to the ground.  It is called a slope mine because the shafts are slanted.  This kind of mining is done when there would be problems drilling shafts straight down.

To take out the minerals out of the mine, the miners make underground rooms to work in. The mining company chooses the best way to get the minerals out.  Most mining is done using continuous mining that uses a continuous mining machine to cut coal from the walls.  This means there is less blasting and drilling and puts less miners down in the mines.  It is safer than the old kind of mining.

Two of the ways that they mine underground are:

Room and pillar mining:   there are intersecting 'rooms' with pillars of coal that hold up the roof.  These pillars are mined when the mine, or a part of it, are closing.  They are careful when they do this because the roof caves in as they leave.

Longwall mining:   usually a machine called a continuous miner slices layers of coal or minerals from the walls.

Rocks, minerals, and gemstones that are mined using the underground mining method:

Alexandrite Amethyst Biotite Calcite Chalcopyrite Magnetite Muscovite Nickel Copper Diamond Gold Emerald Galena/Lead Graphite Gypsum Halite/Salt Hematite Olivine/Peridot Platinum Pyrite Ruby Silver Sphalerite Sulfur Turquoise Uraninite Zinc

Dump trucks Shuttle car Continuous miner Longwall mining equipment Getman Underground Mining Equipment

Machinery used for underground mining: