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GOLD AND SILVER.
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are
found on bedrock. Bench gravels form the largest part of the deposits,
which are reported 50 feet deep and to average $1.50 per cubic yard in
coarse gold. The largest nugget found in this region was valued at
$1,150 and assayed about 0.870 in fineness. One of the companies has a
reservoir and preparations are under way for a hydraulic plant which
will be supplied with water from Colorado River. A Newkirk hydraulic
elevator will raise the gravel to sluice boxes.
Weaver district.—For
over 35 years the dry washes, gulches, and mesas of the Weaver district
in the southern part of Yavapai County have been worked after each
rainfall for the gold which has been caught in depressed areas and
channels. The placer ground containing values extends from 1 to 10
feet in depth over an area of 5 by 8 miles. Stream gravel sand and mesa
soils carry the gold, which, in the gulches, is very coarse, while on
the mesas it is flaky and fine. The largest nugget found was reported
to be worth $400. All of the gold has a fineness of 0.910. During 1912
about 30 placer miners, both Mexicans and Americans, were working with
dry washers, rockers, or, when water permitted, by sluicing, and
produced nearly $5,000 in gold.
San Domingo district.—About
45 miles northwest of Phoenix is San Domingo Wash, in northern Maricopa
County, where dry-placer ground is situated, covering an area 1,200
feet wide by 2£ miles long, with an average depth of 10 feet, and
containing a reported average of about 40 cents per cubic yard. The
surface is scarred by frequent watercourses down which the water runs
in torrents after a heavy rain. It is proposed to work this placer by
taking water from a reservoir built in "Rogers Wash," or by building a
dam in Hassa-yampa River to catch the underground now and to pipe the
water to the placers. Gold has been produced from this locality for
many years by miners operating dry-washing machines.
Teviston district.—During
the wet season dry-placer ground in the Teviston district, Cochise
County, yields a small quantity of gold yearly. About 300 acres have
been reported valuable to a depth of from 3 to 10 feet, the latter
being the greatest depth prospected. Bedrock is from 50 to 75 feet in
depth. Most of the gold is coarse, and the ground by tests has yielded
from 3 cents to $28 per cubic yard. The largest nugget found was valued
at $375. Some cement or caliche has been found in prospecting the
ground, but values have been found in the gravel beneath.
Old Hat district.—An area of 25,000 acres in the Old Hat district,1 Pinal
County, covering nearly the whole of Tp. 10 S., R. 14 E., Gila and Salt
River meridian, distance 4 to 10 miles south from Oracle post office
and 16 to 29 miles north from Tucson , is found containing valuable dry
placer gravel, which has apparently been deposited at intervals by
floods from the Santa Catalma Mountains so as to form a deposit of
nearly equal value from surface to bedrock, there being no pronounced
accumulation of heavy gold at bedrock except in the stream, Canada del
Oro Creek, which passes through the region. The bed of dry gravel is
from 6 feet deep at the creek side to 252 feet at the summit, with an
average thickness of about 150 feet. The deposit is in general a loose
gravel, uncemented. There are, however, alternating strata of deep
red, clayey material. These strata are of nearly
• Burgess, Capt. J. D,, personal letters.
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