GENERAL41483

• Permit No: M1995097
• IBM Index Class Name: General Documents
• Doc Name: BIBLIOGRAPHY WITH INTRODUCTION GLOSSARY OF TERMS AND LIST OF MINERALS
• Media Type: D
• Archive: No

19SO BUREAU OF MINES REPORT
There are two types or stages of brecciation, one parallel
to bedding along and near the Leadville-Weber [Belden]
contact, the other along the cross faults. Exposures are
too limited to state that both breccias are not wholly
related to the cross faults." Gouge is absent or present
only in minor amounts.
Principal structures in the mine are a large number of minor
faults of small displacement nearly parallel to the bedding
[trending northeast-southwest) and several cross faults that
strike northwest-southeast, dip about 45° to southwest, and
displace bedding and the minor bedding faults from a few to
20 ft. northwest. The cross faults are generally zones of
brecciation rather than identifiable fault planes, although
the Emma and Smuggler do include recognizable fault planes.
Brecciation is most extensive where these faults cut the
Leadville-Weber [Belden] contact. As they continue into the
Weber [Belden), the faults die out as local folds. The
existing stopes roughly follow the cross faults.
Orebodies. The Smuggler orebodies are silver-bearing lead-
zinc deposits formed mainly by replacement of limestone and
dolomite at the Leadville-Weber [Belden] contact. In older
areas the ores mined were rich in native silver, pearceite,
argentite, and argentiferous tennantite. Native silver and
some pearceite and argentite were considered to be the
result of supergene enrichment, noted by Spurr (SevRa
MONOGRAPH) to occur to depths up to 700 ft. Principal
sulfides are argentiferous galena, sphalerite, and pyrite,
in very fine grains. Wurtzite occurs rarely. Cadmium
occurs in very small quantities with zinc.JB Much oxidation
has occurred at shallower levels, especially of sphalerite,
resulting in smithsonite, cerrusite, and siderite ranging
from superficial coatings to complete replacement of
sulfides. Gangue minerals are barite, ferruginous dolomite,
calcite, and minor quartz.
Low-grade ores remain in the walls of stopes. The stopes
follow the Leadville-Weber [Belden] contact 2nd show
brecciation in their walls, particularly the hanging walls.
Appearance suggests that the breccias follow the contacts,
but geology indicates the breccias and ore bodies are more
The principal breccias have since been determined to primarily of
sedimentary origin, essentially unrelated to this faulting. See STEGEN
THESIS dnd STEGEN REPORT.
'a Primarily in sphalerite.
Bruce A. Collins - 22 - BIBLIOGRAPHY