Abubakar alghotv is presenting on the eight potential sources of heat in mines for his 8th semester presentation. The eight sources are: 1) Adiabatic compression in shafts and near vertical openings, 2) Rock surrounding openings, 3) Metabolism in human beings, 4) Machinery and lights, 5) Oxidation, 6) Blasting, 7) Rock movement, and 8) Head losses in air flow. Each source is then briefly described in terms of how it contributes heat to the mine environment.

2.  Name: Abubakar alghotv
 Reg. # : 13pwmin0679
 Semester: 8th
 Presentation: Sources of heat of mines.

3. There are eight potential sources of heat in mines
These are

4. 1. Adiabatic compression in shafts and near vertical
openings
2. Rock surrounding openings
3. Metabolism in human beings
4. Machinery and lights
5. Oxidation
6. Blasting
7. Rock movement
8. Head losses in air flow

5. 1. Adiabatic compression in shafts and
near vertical openings.
 Air entering a mine through a shaft is compressed and
heated as it flows downward
 If no interchange in the heat content of the air takes
place in the shaft,the compression occurs
adiabatically(heat is constant).

6. 2. Rock surrounding openings.
 The temperature of subsurface rock rises steadily with
depth.(geothermal gradient)
 The age of rock,the formation and their properties
determine the gradient.
 Heat inflow into the mine workings from the
surroundings is a complex mechanism.
 Mine water is also a profile source of heat in mining
workings.

7. 3. Metabolism in human beings.
 Chemical and oxidation processes within the human
body, termed metabolism, produce much waste heat.
 This is liberated from the human body into the
ambient air by convection, radiation etc.
 The amount of heat liberated depends upon the man,s
activity and environmental conditions.

8. 4. Machinery and lights.
 Essentially all the inefficiency of power operated
machines underground constitutes an addition of heat
to the mine air, since the power losses are converted
directly or indirectly to heat through friction.
 The heat produce by the mine lighting system and
individual cap lamps is generally small, although
essentially the entire electrical energy consumption of
lights is converted into heat.

9. 5. Oxidation.
 Oxidation processes involving the mineral and timber
in mines contribute heat to the mine air.
 In coal mine, this may constitute 80% to 85% of the
total load.
 In ore mines having a high sulfide content, the
addition of heat may also be very great.
 The amount of heat generated by oxidation is difficult
to determine.

10. 6. Blasting.
 Since over half of the energy created by the detonation
of a high explosive is liberated in the form of heat.
 Blasting is usually a very significant cause of
temperature rise in the mine air.
 The exact amount of heat added to the mine air cannot
be calculated directly, since some is absorbed by the
rock.

11. 7. Rock movement.
 Movement of ground due to the geologic causes or
mining subsidence is another heat source which is
difficult to determine.
 Caving or collapse of waste is the most common cause
of heat liberation due to ground movement.
 Some theoritical determinations have indicated that in
coal mines, rock movement may account for about 10%
of the total heat produced.

12. 8. Head losses in air flow.
 All friction and shock losses which must be overcome
in mine air flow, convert energy into heat. Essentially
all the static horsepower of moving air is converted
into heat.

13. Thank you