Page 199 - calmining1890

FRESNO COUNTY. 193
to the present time, one being one hundred and forty-two feet in length
and the other, as far as explored, fifty-two feet. There are three levels
in the mine, the longest being one hundred and fifty-two feet. Both
Giant and Hercules powder are used in the mine, and about sixty
pounds is the amount consumed monthly. Four dollars is the cost of
mining per ton. The method of treating the ore is by the "arrastra"
process. The company has two arrastras, run by horse power, reducing
one and one fourth tons of ore each twenty-four hours, which averages,
in free gold, $65 per ton. The sulphurets average about 1 per cent, but
none are saved, although tests made show them to be quite rich. The
company contemplate the erection of a five-stamp mill. During the
year 1890, from January to May, one hundred and thirty-five tons of ore
were reduced, yielding $62 50 per ton.

BIG DRY CREEK MINING DISTRICT.

The Big Dry Creek Mining District is situated about twenty-four miles
northeast of Fresno City, T. 11 S., R. 22 E., and covers Sections 29 to
36, inclusive. Passing through this section is a belt of slate running
northwest, which direction is the general trend of the stratification
through this county, the course being, in general, with the direction of
the main ridges. This belt is about eighteen miles in length, varying
from one to three miles in width, and is in contact with a narrow belt
of serpentine on its eastern side. There are but few mines in this dis-
trict, and at this writing only one on which work is being done, namely,
the Confidence Mine.
CONFIDENCE MINE.

The claim is at an elevation of six hundred and sixty-five feet above
sea level. It was located in 1874, and is one thousand five hundred feet
in length by six hundred feet in width. It is four miles northeast from
Academy Station by road. The vein courses northwest and southeast,
and dips to the east at an angle of 85 degrees. Its average width is three
feet. The mine is opened by a tunnel three hundred and sixty feet in
length, and upraises have been made from it to the surface in each of
the first two ore shoots, there being three shoots in the mine; a shaft
has been sunk in the third shoot from the surface, forty feet in depth.
Both walls are of slate. The ore shoots are respectively eighty feet,
seventy feet, and fifty feet in length. The greatest vertical depth reached
by the working tunnel is one hundred and fifty feet from the surface.
The tunnel is well timbered with round pine for two hundred feet of its
length. The explosive used is Hercules powder, and but very little of
it is consumed, as the ground is quite soft. The cost of mining per ton
does not exceed $1 50. About one thousand seven hundred tons have
been milled, and have averaged $9 per ton. The mill is a five-stamp
mill, situated about one and one half miles by road from the mine, and
is run by a sixteen-foot overshot wheel, with two and one half feet face.
The ore contains about one half of 1 per cent sulphurets, but none have
been saved. The stamps are of six hundred and fifty pounds weight.
The drop is six inches, and the stamps drop eighty-five times per minute,
crushing one ton per stamp every twenty-four hours. The height of
the discharge above the dies is five inches. The screens are of brass