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River Mining
By R. L. DUNN, E.M.
(excerpted from the Ninth Annual Report of
the State Mineralogist for the year ending December 1, 1889, by the California State
Mining Bureau.)
 River
mining is a branch of placer mining that is carried on in the channels and beds of rivers
and large streams. Practically it may be considered as including the mining of such deep
bars as have to be exploited below the surface of the water in the adjacent river. River
mining is not local to California, though undoubtedly carried on to a greater extent here
than in any other gold-bearing district in the world.
As contrasted with gulch and ravine mining
and hydraulic mining, it is dry season work, only practicable when the rivers are in their
low water stages. Probably no other branch of our gold mining industry is subject to more
uncertainty under ordinary conditions than is river mining, yet in no other branch are as
large returns possible with comparatively small capital.
In the early mining history of California,
after the rapid working out of’the shallow placers of the high bars, attention was
turned to the river channels as the next most certain source for a large gold yield, and
in 1852, 1853, and 1854, a very large amount of this mining was done, and most of the gold
yield of the State at that time came from this source. During these years all of the large
gold-bearing rivers in the State were worked, but the industry gradually declined in
relative importance with the discovery and opening of the mines in the old river channels.
Hydraulic mining from 1857-58 practically extinguished river mining in many of the rivers
by reason of tailings covering up the river claims, and it is only since 1880, coincident
with the restriction of hydraulic mining, that the attention of mining men has been
directed to the river channels.
The rivers which have been and are now the
locality of this branch of mining, are the Klamath, Salmon, and Scott Rivers, Trinity
River, and the main Sacramento above Redding, Feather River above Oroville and its four
large forks, Yuba River above Smartsville and its main forks, Bear River, the North,
Middle, and South Forks of the American River, Cosumnes River, Mokelumne River, Stanislaus
River, Tuolumne River, and Merced River. Of these the Cosumnes, Mokelumne, Stanislaus, and
Merced Rivers are practically worked out and abandoned, certainly so far as any large
operation is concerned. The low water flow of these streams is comparatively small and
easily controlled, and the tailings from hydraulicking did not get into the river channels
until they had been thoroughly worked.
The very little mining in these streams of
late years has been by small companies of Chinese handling over tailings and the few
unworked spots overlooked by the old miners. The South Fork of the American River, and
Trinity River, are practically abandoned, though it is probable that in both streams there
yet remain unworked portions of the bed that will pay. The large volume of water in the
main Sacramento River above Redding has prevented work in that stream to any extent, and
it is not likely that any successful mining on a large scale will be possible there till
the low water volume of the stream has been materially reduced by diversion for
irrigation. The remaining streams are thus prac-tically the only available ones for this
branch of mining. Of these the Yuba and its forks, Bear River, and the North Fork of the
American con-tain large areas of unworked ground known to be rich, but buried beneath
large masses of hydraulic tailings. These tailings, however, contain in the aggregate a
large amount of gold, and have thus enriched the riverbeds for future mining. The winter
floods, with the cessation of hydraulic mining, are now ground sluicing on a tremendous
scale, washing the tail-ings that have been slacking and disintegrating for years, and
concentrat-ing the gold they contain into a smaller bulk of gravel. A
few years of this operation and these rivers can again be profitably mined.
The localities of active mining operations in
this branch of mining at the present time are confined to the Klamath, Salmon, and Scott
Rivers, in Siskiyou County; the Feather River in Butte County, and the Middle Fork of the
American River in Placer and El Dorado Counties, with a little work by Chinese high up in
the forks of the Yuba River.
Klamath River ever since the discovery of
gold in its bed has been con-tinuously mined and is still a long way from being worked
out. The conditions for river mining in this stream are very favorable. Though carrying a
large volume of water, it has nearly everywhere a considerable grade and velocity of
current with no great depth. Hydraulic mining tailings have not accumulated and covered up
the claims, and mining in it has been so continuous that the location of the worked and
unworked portions. of the bed are well known, and there is not the uncertainty on this
point that is the case with the other noted streams. At the present time there are about
twenty-five claims being worked on the Klamath and Salmon Rivers, employing three hundred
men. Operations in this locality are generally on a small scale and involve the use of but
little capital.
The Feather River, in Butte County, is the
location of the two most extensive river mining operations in the State. These will be
considered in detail further on. The Middle Fork of the American River, though worked very
extensively in the fifties, still contains much valuable ground, particularly in deep bars
and in portions of the main channel that the early miners could not drain or bottom.
A considerable amount of river mining is now
being done at several points on this stream, and new enterprises are under consideration
for the immediate future; the successful results of the present work having encouraged the
investment of capital.
The rivers in which river mining is carried on run in narrow canons more or less difficult
of access. Usually the hill and mountain slopes rise directly from the water’s edge,
but the streams meander for portions of their course from side to side of narrow valleys,
leaving small flats, or “bars,” as they are termed by the miners, alternately on
one and the other side of the stream. The formation of these bars is due
to the action of the flowing river. During the period of its gradual erosion, slides from
the hillsides, or the accumulating debris of floods, have changed the course and channel
of the streams, and widened the cañons to narrow valleys.
These bars, sometimes high above the present
channel of the river, sometimes lower than it, are nothing but portions of its former bed.
Often a secondary erosion so changes them that their identity is lost, but wherever they
are, the dynamic and hydraulic forces that formed them made them natural riffles and
storehouses of placer gold. These deep bars were the dream and the snare of the early
miners, probably more effort and capital being expended in unsuccessful attempts to mine
them than in any other of the early mining operations, the fabulous yield of the few
successfully worked deep bars and adjacent river-bed encouraging similar undertakings,
that were only abandoned after successive failure had demonstrated the inadequacy of the
appliances and methods employed.
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