Old Mines of Southern California: Desert-Mountain-Coastal Areas Including the Calico-Salton Sea Colorado River Districts and Southern CountiesFairbanks, Harold W. (Harold Wellman)
History
Old Mines of Southern California: Desert-Mountain-Coastal Areas Including the Calico-Salton Sea Colorado River Districts and Southern Counties
Fairbanks, Harold W. (Harold Wellman)
Geology -- California, Southern; Mines and mineral resources -- California, Southern
The ores carry on an average about 30 ounces of silver, and for the most
part are very free-milling. At the time of my visit an estimate of this
silver ore on the dump and in the mine placed its value at,
approximately, $20,000. In one portion of this rather remarkable ore
deposit considerable quantities of native sulphur occur, associated with
a brownish iron oxide and silicious gangue material. As depth is
attained the oxidation is less marked, and at 80 feet has apparently
given place entirely to sulphuretted ores and silicious rock, low in
silver.
The strike of this shoot of ore is north 50° west, dipping northeast at
an angle of 70°. At the depth of 65 feet below the croppings, in sinking
a winze, which in its downward course follows a slip northward but is
vertical as compared with the dip of the vein, a bunch of high-grade,
partly oxidized copper ore was discovered. Further development
discovered other pockets or bunches of copper ore carrying usually about
15 ounces in silver per ton. When a depth of 120 feet had been reached a
crosscut tunnel was run in 235 feet. The course of this tunnel is north
5° west. The face, however, had not reached a line representing the dip
of the surface shoot. The tunnel has been connected by winze with the
upper workings, and considerable other development accomplished.
By means of these workings the peculiarities of the mine have been
exposed. The series of faults which have resulted in the deposit of a
considerable quantity of silver ore have been accompanied by another
series of fractures which, while independent of the former, were,
perhaps, contemporaneous. The second series exhibit no parallelism, but
strike in various directions. Along these fault planes occur bunches of
copper ore, principally variegated pyrites (bornite), chalcopyrite, and
a black “earthy” sulphide, having a shining streak, not sectile,
probably a variety of copper glance.
These ores are sometimes associated with iron sulphide, but most of this
class may be easily sorted. One class of ores occurs intermingled with
the gangue containing about 15 per cent copper. This ore can be
separated on any concentrating machine such as a jig, the resulting
product being high grade. The ore shipped to Swansea has averaged over
33 per cent copper and 15 ounces silver per ton.
[Illustration: _LONGITUDINAL SECTION OF TIPTOP MINE
LAVA BEDS DISTRICT SAN BERNARDINO CO._]
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account