Last updated: 7 March, 2020 1:24
Persistence of Ore in Depth at Cripple Creek (1919, April 26)

The Mining and Scientific Press,
April 26, 1919 (page 556)

Source had no images, so I used a couple images from my collection.
Persistence of Ore in Depth at Cripple Creek
By Unknown

Recent correspondence from Cripple Creek, published in the Review of Mining, reports numerous discoveries of rich ore in the district. Some of these have been made by lessees, others by companies, at depths varying from 800 to 2130 ft.

Cresson Mine C.C. District, Colo.
Cresson Mine C.C. District, Colo.
Photo by Leslie

The Cresson company has found an extensive shoot at 800 ft., while the Portland is developing two rich veins from the Roosevelt drainage-tunnel, at a depth of 2130 ft. The elevation of the Portland's new workings is 8113 ft. above sea-level.

On the other hand, the annual report of the Vindicator Consolidated contains the following:

"Early in 1918 development was discontinued on the 20th level, the bottom of the Golden Cycle shaft. On this level a total of 4240 ft. of work has been done, and no ore of a commercial grade exposed.

Vindicator Shaft Nos. 1, 2, and 3
Vindicator Shaft Nos. 1, 2, and 3

This work has systematically explored the known ore-zones which at this level should possibly produce ore. The vein-systems were found in place and the fracturing was strong and well defined, and with a general physical appearance favorable to ore-deposition.

However, the value necessary to make commercial ore was lacking. This level is at a depth of 2150 ft. from the collar of the shaft, and at an elevation of 7020 ft. above sea-level.

The productive areas in the property maintained well with depth to an elevation of about 8300 ft. In sinking below this there was a gradual but marked decrease in the production of the areas, the ore-shoots being more broken up, and showing a decrease in the average grade of the ore produced.

Extensive work has been done on the 20th level with the view of developing ore below a possible barren zone existing at the elevation of the 19th level, with negative results.

There are possibly existing orebodies at a greater depth, but it is the opinion of the operating-staff, from a thorough study of the habits of the existing orebodies, that there will not in this property be sufficient ore opened at a greater depth than that to which exploration work has been carried to warrant the expenses of sinking and exploring.

However, this does not mean that exploration should stop, as there is a considerable area on the upper levels of the property that has not been thoroughly prospected, and it is the intention of the management to explore this ground during 1919.

Due to the intense labor shortage during the year 1918 this work was impossible."


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