246 GEOLOGY AND GOLD DEPOSITS OF THE CRIPPLE' CREEK DISTRICT. 
April, 1904, 171 feet above the portal of the Standard tunnel. This gives a flow 
gradient, to the mouth of the tunnel, of about 1 to 82, which, in view of the condi¬ 
tions of flowage through the rocks, does not preclude the possibility that the Standard 
tunnel has aided in lowering the water in these mines. On the other hand, during 
the seventeen months ending December 31, 1904, the El Paso tunnel discharged 
3,550,000,000 gallons of water without perceptibly relieving the mines at Altman and 
Independence. We are forced to conclude that from a practical standpoint the 
existing tunnels do not aid the Vindicator, Lillie, Hull City, Findley, and Golden 
Cycle mines. The same statement probably applies to the Isabella mine, which 
may occupy a local water basin having only imperfect flowage connection with 
that of the Vindicator mine. The long idleness of this mine and the relatively 
high level of its sump (PI. XX, p. 242) leave us somewhat in doubt as to the recent 
behavior of its water. The portion of the district probably drained to a practical 
extent by the El Paso tunnel is shown in fig. 23 (p. 250). 
The isolation of the Vindicator water basin from those of the west side and 
Victor groups is apparently not due to the intervention of any continuous zone of 
massive rock, such as a phonolite or basic dike. The fissure systems of the Vindi¬ 
cator, Gold Cycle, and other mines in the vicinity traverse breccia as well as syenite 
and latite-phonolite, and were the breccia generally permeable there is no reason 
why the water should not drain westward. But the experience gained in under¬ 
ground workings, notably in the Elkton mine, shows that unfissured breccia may be 
practically impervious. The fissure systems of the Altman and Independence 
mines have a general northwest-southeast trend. Between these fissures and those 
those of the west and southwest slopes of Bull Hill is a zone of breccia with intrusive 
masses of syenite and latite-phonolite, which contains, so far as known, no important 
cross fissures that might serve as water channels. In the absence of notable east- 
west or northeast-southwest fissures in this zone is probably to be found the chief 
explanation for the failure of existing tunnels to drain the mines near the eastern 
side of the volcanic neck. 
FUTURE DRAINAGE. 
Mr. Hills has shown® that it is practicable to tap the Cripple Creek volcanic neck 
from the southwest by tunnels at various altitudes down to 6,600 feet. Taking the 
Blue Bird shaft as an objective point, he estimates the lengths of some of the possible 
tunnels as follows: 
* 
Estimated length of possible tunnels in Cripple Creek district. 
Elevation 
of portal 
above sea. 
Length of 
tunnel. 
Feet. 
Feet. 
8,600 
16,000 
8,400 
18,400 
8,200 
19,600 
8,000 
21,000 
7,500 
23,900 
7,000 
29,000 
6,000 
36,000 
a Ninth Ann. Rept. Portland Gold Mining Company, 1903. 
