MINES OF GLOBE HILL. 
285 
layers of gypsum, manganese, oxide, and iron ocher. Scattered through the vicin¬ 
ity but parallel to the group of columns of gypsum there are patches as well as 
seams of fluorite sand, consisting of particles of crystalline silica, stained purple by 
admixture with fluor-spar. The upper levels also show bands of * * * pure 
kaolin.” For further discussion in regard to this occurrence see page 220. 
PLYMOUTH ROCK MINE. 
The Plymouth Rock property, likewise owned by the Stratton estate, is 
located on the west side of Ironclad Hill, about 600 feet southwest of the Deerhorn 
shaft. The production is not known. Developments consist of a shaft between 
800 and 900 feet deep, the principal workings being on a northeasterly trending 
vein, possibly the same as the Ironclad. From the lowest (ninth) level drifts 
extend for a couple of hundred feet west, northeast, and southeast. The shaft 
and workings, which were inaccessible in 1904, are reported to be throughout in 
thoroughly oxidized breccia. The deep exploration is said to have failed to develop 
any ore bodies, though much of the soft rock gives traces or very low assay values 
in gold. 
The Chicago tunnel, the elevation of which is about 9,700 feet, extends from 
Poverty Gulch to the Plymouth Rock shaft, with which it connects about 700 feet 
below the surface. The tunnel extends for 2,000 feet in an east-southeast direction, 
and then changes to a few degrees north of east and continues for about 2,200 feet 
farther, to the connection with the shaft. From its portal to the end the tunnel 
traverses normal breccia and aside from the few basalt dikes cut in the first 1,200 
feet there are no intrusive masses present. The breccia is in general not oxidized 
and contains a little pyrite. A specimen from a point 1,200 feet from the shaft 
consists of normal fine-grained breccia of phonolite and granite, with much finely 
distributed pyrite. The ferromagnesian silicates have been converted to cliloritic 
material. Otherwise there is little alteration. About 1,000 feet from the end 
the rock within a short space becomes entirely oxidized and softened; it is filled 
with kaolin, limonite, and oxides of manganese; sometimes it also contains gypsum. 
At the end the rock is extremely soft, and close timbering is necessary. There are 
no distinct veins, but seams, usually with much kaolin, run in various directions. 
The rock is said to contain small assay values throughout, ranging up to SI.50 
per ton in gold. Branch drifts from the main tunnel enter schist. 
A thousand feet east-northeast of Plymouth Rock shaft is the World’s Fair 
claim, also belonging to the Stratton estate. A shaft about 200 feet deep has been 
sunk on it and some drifting has been done on a northerly trending vein. A little 
ore is said to have been shipped. 
IRONCLAD MINE. 
The Ironclad mine is situated a few hundred feet southwest of the Plymouth 
Rock and is operated at present by the Cripple Creek Homestake Mining and Reduc¬ 
tion Company. The total production is stated to be 8225,000. A considerable 
amount of low-grade oxidized ore has lately been encountered on the claims adjoin¬ 
ing the Ironclad on the southeast; this ore is at present mined and milled by the 
same company, the process employed being that of simple cyaniding without 
13001— No. 54—06-20 
