Page 447 - calmining1890

PLACER COUNTY. 423

For the sake of illustrating this theory (see Geological Map of Placer
County), let us begin on the deposit above Volcanoville in El Dorado
County and follow a northwesterly course across Forest Hill to Wiscon-
sin Hill and Iowa Hill; thence westerly, making confluence west of Iowa
Hill with Gold Run channel; thence following course of American
River Canon and the remaining patches in its course westerly to Bowl-
der Ridge and the plains. The elevation of bedrock and similarity in
character of deposit and capping of remaining patches between Iowa
Hill and Bowlder Ridge offer a reasonable basis for the theory that the
ancient river flowed westerly in the direction near that marked by
remaining patches between Iowa Hill and Bowlder Ridge.
Accurate surveys, however, are the only reliable means of determining,
delineating, and reconstructing with any degree of certainty the system
of ancient rivers of the Tertiary.
A survey of the volcanic-capped ridge above Damascus, made by the
writer in the year 1878, maps of which are on file in State Mining Bureau,
resulted in delineating and locating the course of the beds of an exten-
sive and valuable system of auriferous channels now being worked at
Red Point, and in course of development at Indian Springs, Golden
Fleece, New Basel, Macedon, and Hogsback Mines.
Prior to the anti-debris litigation there were thirty-three hydraulic
mines operated in the Iowa Hill District, all of which are now closed.
Since the cessation of hydraulic mining several of the mines have been
reopened for working by drift process, giving satisfactory and profitable
results.
The Waterhouse & Dorn Mine.

The Waterhouse & Dorn Mine is located at Wisconsin Hill, and has
an area of one hundred and sixty-three and thirty-seven one hundredths
acres, covering several thousand feet of the Morning Star channel.
The mine is opened with a tunnel eight hundred feet in length, from
which a shaft is raised and a station opened in the cemented blue gravel.
Gangways have been driven up and down the course of channel, expos-
ing a deposit of rich gravel similar to that in the Morning Star Mine.
The mine is provided with a three-drill compressor plant of the Rix
& Firth pattern, also two of Bryan's twenty-ton roller mills. A ditch
owned by the company, having a capacity of five hundred inches, fur-
nishes water for power to drive both mill and compressor.
The power drills in use at the mine are the Ingersoll and National,
which work to perfection in the hard cemented gravel. They are used
in the breasts, as well as in the drifts and gangways, and are found much
cheaper than hand drilling.
The gravel extracted is first run through a rockbreaker and fed by
self-feeders to the Bryan roller mill, which is provided with No. 4 wire
screens. The gold is recovered on plates. The gravel extracted yields
$9 per carload of one ton. The company intend erecting a twenty-stamp
mill, which will be more suitable for crushing hard cemented gravel
than mills of the roller pattern.
It is unnecessary to give detailed descriptions of the drifting opera-
tions at the Morning Star and other mines in the vicinity, as they were
fully described in the Annual Report of 1888. They are, however,
working steadily and are in a prosperous condition.