Min-218 Lab #4
Estimating Natural Ventilation
Natural ventilation is generated and maintained by thermal energy due to temperature differences inside and
outside of the mine. Although not entirely true, this difference can be roughly estimated by physical
elevation as well as the difference in vertical depth from surface to the underground workings.
The following chart can be used to roughly estimate the amount of natural draft by knowing temperature
difference (between inside and outside of the mine) and mine's elevation.
80°F Te
mperatu
re Diffe
rential
1.00
70°F Tem
perature
Differen
tial
0.85
60°F Temp
erature Dif
ferential
0.75
0.71
50°F Tempe
rature Differe
ntial
40°F Temperat
ure
0.50
Differential
30°F Temperature
Differential
20°F Temperature Differential
Mine B
0.25
Mine A
Natural Ventilation, in. W.G.
1.25
0
1,000
2,000
3,000
4,000
5,000
6,000
Elevation above Sea Level, Ft.
Variation in NVP Per 1,000 ft Elevation for Varying Temperature Differentials