CHAPTER XIII.—UNDERGROUND GASES AND TEMPERATURE. 
SUBTERRANEAN GASES. 
GENERAL STATEMENT. 
During the earlier years of development in the Cripple Creek district no unusual 
mine gases were observed, but as the shafts were deepened and the workings extended 
several properties began to experience much annoyance and even serious interfer¬ 
ence with the work, often in spite of vigorous measures to insure ventilation. At 
least one mine has been forced to close down, largely on account of this subtle and 
insidious enemy, and several miners have perished by it. The trouble appears to 
increase as depth is gained, though at what rate can not as yet be ascertained. 
Certain localities are almost exempt, while in other mines not far distant the gas 
issues in large quantities. The gas lias proved to be a mixture of nitrogen and 
carbon dioxide, with some oxygen. 
The subject seemed of sufficient importance to warrant a careful investigation. 
Such facts as have been ascertained are set forth in the following paragraphs. 
COMPOSITION OF AIR. 
Normal air should have the composition shown in the following table: 
Composition of normal air. 
• 
Dry 
Volumes. 
air. 
Weight. 
Average 
air 
(volumes). 
Oxygen. 
20.92 
78 “179.04 
. 94 j 
.04 
23.10 
{ 
20.6 
78.5 
.04 
.86 
Nitrogen. 
Argon. 
Carbon dioxide. 
Water.. 
100.00 
100.00 
100.00 
Comparative specific gravity of air and various gases. 
Air. 1.0000 
Oxygen. 1. 1056 
Nitrogen.9713 
Carbon dioxide. 1. 5290 
The amount of water gas naturally varies and may reach 3 per cent by volume. 
In moist climates it would perhaps average 1.3 per cent by volume or 0.84 per cent 
by weight. The air at Cripple Creek is ordinarily dry, and the elevation above sea 
level is without influence on its percentage composition." 
252 
a Erdmann, H., Lehrbuch der anorganischen Chemie, Braunschweig, 1902, p. 223. 
