it
has not been a paying undertaking. By dry washers, however, men have
been able to make $3 a day. The gold here is in a gravel conglomerate
at the north terminus of the San Dias.
Las Animas.—In
the Las Animas district, Sierra County, dry-wash and gulch mining have
been productive about 6 miles northeast of Hillsboro, the nearest post
office. The dry placers cover several square miles from one-half inch
to several feet in depth. Gold is practically all worked on false
bedrock. Nothing is known of the original bedrock. Fake tests have
averaged $1.25 per cubic yard, but average working tests from 22 to 25
cents. The largest nugget-found was valued at $85, and the fineness of
the gold ranged from 0.945 to 0.956. This property was worked about six
months in 1912 with the use of the Quenner trommel mill and Hilltscher
Bros, dry concentrator. The machinery was operated by gas-engine power.
These placers, of which the Luxemburg claims are the most important,
contain a piece of undisturbed cement gravel left standing of about 20
acres, which lies at the head of all the placer field. Gold is found on
a false bedrock and as a rule is very coarse. The cement is worked
sometimes to the depth of 8 feet to bedrock and averages in thickness
about 5 feet. The average value in gold disseminated through the cement
is about $2 per yard. Bedrock is soft, but the cement above it, which
varies from a few feet to 30 feet, is so hard that every foot of the
pay streak has to be blasted with powder. The Quenner machine handles 5
tons an hour and throws out the largest part of the rock and bowlders.
The discharge is run over a concentrator made of iron, which catches
all of the coarse gold that will not pass the staves of the Quenner
trommel. The fine passes over four dry tables built on the plan of a
simple bellows dry washer. The Quenner machine is driven by an 8
horsepower gas engine and the tables and conveyor by a 5 horsepower
engine. Extraction is reported to be over 90 per cent when the material
worked is perfectly dry. A paper 1 prepared by members of the Survey gives descriptions of the placer regions of New Mexico.
DRY PLACERS IN CALIFORNIA. By Charles G. Yale.
An
attempt was made during 1912 to ascertain the condition of the industry
of dry washing for gold in California, particularly in the semiarid and
desert regions, but it was not as successful as hoped for. Most of the
men working the dry placers are nomadic in their pursuits and only go
to the camps during the season when the weather is not too hot. These
localities, too, are usually isolated, at points where there are no
towns or communities.
There
is some dry washing going on in the Summit and Goler districts, near
Randsburg, Kern County, but those who control the properties are
reticent as to results. Work of this kind is also being done about 12
miles southeast of Ricardo, in the same county, in Last Chance and
Black Mountain camps, but no output has been reported there lately.
Christmas Camp, 24 miles north of Garden Station, is being worked by
dry washing. At Coolgardie Camp, 20 miles north of Barstow, some gold
from ancient river bed gravel was obtained
i
Lindgren, Waldemar, Graton, L. C, and Gordon, C. H., The ore deposits
of New Mexico: Prof. Paper U. S. GeoL Survey No. 68,1910, pp. 74-76.
