Mineralogy Lecture - 4

Tishk International UniversityEngineering FacultyPetroleum and Mining Department

Mineralogy

Third Grade - Fall Semester 2021-2022

Lecture - 4

Instructor: Dr. Shwan Omar Ismael

Outlines

➢ Underground Mining

➢ The types of Underground Mining

➢ Extracting metals from their ores

Petroleum and Mining Engineering Det. Mineralogy Lecture 4

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Underground mining uses horizontal,

sloped, and vertical tunnels to locate

and extract the ore.


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Underground mining must follow the

ore vein or coal seam. Following the

seam underground can be difficult and

costly if the rock is faulted.


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Most underground mines have an

access shaft that is sunk from the

surface down to the many levels that

can be worked.


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Each of the horizontal levels is

connected to the shaft by a tunnel

called the drift. The shaft contains a

cage for carrying both the workers and

ore between the different levels.


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The shafts also contain pipes to pump in

air, carry electricity, and pump out

water. With underground mining, it is

more costly to obtain the ore, so miners

attempt to access the ore in the most

feasible way possible, while bringing as

little waste as necessary to the surface.


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One common method of underground

mining is called the room-and-pillar

method, which keeps the shaft from

collapsing underground and trapping

the miners. In this procedure, a system

of pillars is left unmined.


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These undisturbed pillars are what hold

up the ceiling.

Another underground method is called

longwall mining. In this procedure, a

long wall is established for mining, using

an access tunnel at each end.


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The wall is then mined, and the roof is

held up by mechanical jacks. As the long

wall is mined out, the jacks are

removed, allowing the roof behind to

collapse in a controlled way. When the

rocks are hard, mining has to be done

with pneumatic drills and blasting.


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Some minerals are insoluble and can be

removed as an emulsion, which is a

mixture of water and tiny particles of

material. This process operates on the

fact that the mineral has a low melting

point, but is insoluble.


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Superheated water at 329°F (165°C) is

pumped underground through a pipe,

which melts the mineral. Because the

mineral is insoluble, it remains

chemically uncombined. Inside the main

pipe are two smaller pipes.


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Compressed air is pumped down a

central pipe, and a mixture of the liquid

mineral, water, and air is pushed up

through the remaining pipe. This is

called the Frasch process, named after

its inventor Herman Frasch, an

American chemist, in 1891.


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Brine-solution mining is another

method of underground recovery of

minerals. In particular, salt, potash, and

trona (sodium carbonate) are all soluble

and so can be removed in solution.


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A well is sunk to the mineral bed. It is

lined (cased), and pipes are inserted

into the well.


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Water is then injected into the well

through part of the tube system.

Because the brine is denser than the

freshwater, it sinks to the bottom. The

brine is then sucked up through another

part of the tube system.


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The areas where the solution is

extracted can be huge, up to 328 feet

(100 m) across. When the brine reaches

the surface, the water is evaporated

away using special vacuum flasks.


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Mining Processes

Specific mining processes must occur in

order to obtain mineral resources. They

must be extracted from the Earth,

processed and refined, and then

transformed into finished products.


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Extraction

Metals are extracted from their ores

using chemical reactions. In a reaction

to extract metal from its ore, the ore

serves as one of the reactants, and the

metal becomes one of the products.


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The higher in the reactivity series the

metal is, the more difficult it is to

extract from its ore. Because of this,

these metals are often more expensive

to produce and buy.


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The main methods of extracting metals

from their ores are decomposition,

displacement, and electrolysis. All the

methods of extracting metals from their

ores are also known as smelting.


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Summary

❑ Underground mining uses horizontal,

sloped, and vertical tunnels to locate

and extract the ore.


24

Summary

❑ Each of the horizontal levels is

connected to the shaft by a tunnel

called the drift. The shaft contains a

cage for carrying both the workers

and ore between the different levels.


25

Summary

❑ One common method of underground

mining is called the room-and-pillar

method, which keeps the shaft from

collapsing underground and trapping

the miners. In this procedure, a

system of pillars is left unmined.


26

Summary

❑ Long wall Mining is established for

mining, using an access tunnel at each

end. The wall is then mined, and the

roof is held up by mechanical jacks.


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Summary

❑ Frasch process will hapen when;

Compressed air is pumped down a

central pipe, and a mixture of the

liquid mineral, water, and air is

pushed up through the remaining

pipe.


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Summary

❑ Brine-solution mining, In

particular, salt, potash, and trona

(sodium carbonate) are all soluble

and so can be removed in

solution. A well is sunk to the

mineral bed.


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Summary

❑ Metals are extracted from their

ores using chemical reactions. In a

reaction to extract metal from its

ore, the ore serves as one of the

reactants, and the metal becomes

one of the products.


30

Summary

❑ The main methods of extracting

metals from their ores are

decomposition, displacement, and

electrolysis.


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Mineralogy Lecture - 4

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