262 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE CREEK DISTRICT. 
El Paso and C. K. & N. mines .—An abundant flow of gas, in part carbon 
dioxide, issues from some of the fissures of the C. K. & N. lode, at a depth of 300 
feet, so that a candle held to such an opening is immediately extinguished. Owing 
to the connections with the El Paso and Old Glory shafts, the mine was well 
ventilated and the gas was causing no particular inconvenience. 
In the El Paso tunnel, a few hundred feet from the regular El Paso workings, 
gas sometimes issues from granite near the phonolite in such volumes that the 
rapidly flowing stream of water coming from the heading of the tunnel and the 
resulting brisk circulation of air in the drift are insufficient to carry it away. 
At such times candles, torches, and acetylene lamps are extinguished. While no 
actual fissures were found from which the gas issued, the zone from which gas 
comes is narrow and well defined. 
Pointer and Mint mines .—The Mint shaft is 750 feet deep and is sunk in breccia, 
while that of the Pointer is 530 feet deep, latite-phonolite being the country rock. 
Both mines contain much gas, which often seriously interferes with their operation. 
This gas collects in nearlv all crosscuts and drifts not in the direct line of ventilation 
between the two shafts. A considerable part of the workings was found to be 
inaccessible from this cause at the time of visit. 
Poverty Gulch .—Of the mines in this vicinity the Abe Lincoln contains a small 
amount of gas in the winze below the Cripple Creek and Chicago drainage tunnel, 
close to the Half Moon vein. There is also a little gas in the winze below the 
500-foot level. 
In the Mollie Kathleen the air on the 700-foot level is often so bad that candles 
fail to burn, especially when a brisk southwest wind is blowing. 
In the C. O. D. mine, the lower levels of which are not worked at present, 
gas stands several feet deep above the bottom level, 800 feet below the surface. 
Conundrum mine .—Tins mine, which is situated on the eastern slope of Gold 
Hill, contains at times a large amount of gas, which interferes very seriously with 
the working of the property. The deposit consists of a basic dike in a very much 
shattered gneiss, whence the gas escapes in large quantities. The workings con¬ 
sist of an adit 300 feet long with an incline shaft at the end. The lowest (sixth) 
level is 625 feet below the adit, and the workings where most of the gas issues 
are approximately 725 feet below the surface. The workings, as shown in fig. 24, 
partly connect with those of the adjoining Midget mine, which is also much troubled 
by gas. The ventilation is not perfect, the air current entering an old incline near 
the mouth of the adit; thence descending through the workings and winzes to level 
6, from which point it ascends through the incline and leaves the mine through the 
adit. The connection with the Midget mine on level 6 is closed by an air curtain. 
It will be seen that there is practically no difference in level between the intake 
and the upcast current. An attempt is made to increase the ventilation by a sail 
stretched above the winze at the mouth of the adit so as to catch the prevailing 
southerly or southwesterly winds. On days of low barometer gas enters the mine 
from practically all points on level 6, and when the barometer is exceptionally 
low it may fill the whole mine. Work is frequently impossible for many days in 
succession. On March 20, 1904, when the barometer stood at 19.9 inches at the 
portal, the mine was visited. Candles would burn at the shaft station on level 6, 
