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J. Ross (John Ross) Browne.

Reports upon the mineral resources of the United States [electronic resource]

. (page 24 of 55)

inanition for want of the fostering care of the general government. As will be
explained anon, to smelt the ores on this coast, with the present price of fuel



160 RESOURCES OF STATES AND TERRITORIES

and the metal when made, would be but a partial and temporary remedy, the
nal success of which is involved in doubt. The recommendation of the chair-
man of the national revenue commission on this very point explains the only
effectual plan that will secure the extended development of the copper resources
of this coast. The following is a copy of the commissioner's recommendation
referred to : " The commission therefore recommend that all excise duties on
domestic copper be repealed ; and that the duties on imported copper ores and
copper be advanced to a moderate extent, or sufficient to relieve the copper
m.ning interests of the United States from the depressing effects of the internal
taxes upon their supplies, and to give to it as good a -standing in our own mar-
kets, with reference to foreign competition, as they had before the present taxes
were imposed."

4.-REDUCTION OF ORES.

Processes in use for smelting and concentrating the ores. Numerous plans have
been proposed and tested for the purpose of smelting and concentrating the cop-
per ores found on this coast, none of which, for causes to be stated, have been
entirely successful, though several of them have been partially so. A detailed
description of all these various processes, and of the furnaces and apparatus
used, while it might be both interesting and instructive, would be out of place
in this report. Most of these plans which have been tested, on the large scale,
have possessed some novel principle, which might be of advantage if employed
in combination with old established processes, by those who possess the neces-
sary skill, experience, and judgment to admit innovations upon systems under
which they may have been educated. This seeming digression is intended to
explain the principal cause of the failure of some of the most costly works that
have been erected for the purposes to which this portion of the report refers. In
not a few cases, those having charge of these works appeared to labor under
the impression that it was so absolutely necessary to follow the old patterns in-
troduced from their native land, that some German, French, and Cornish opera-
tives seemed to attribute their failure to the fact that the laborers employed,
and the materials used, did not understand the German, French, or Cornish
language.

Early in 1862, works of an experimental character were erected at Antioch,
on the banks of the San Joaquin river, near the base of Mount Diablo, for the
purpose of testing the adaptability of the coal obtained in that vicinity, for
smelling purposes; many persons, supposed to be authorities on the subject,
expressing the opinion that such coal was unsuited for the purpose.

These works were erected under the direction of Mr. Thomas Price, an ex-
perienced Welsh copper miner, who has for several years been acting as agent for
the Swansea smelters* for the purchase of copper ores on this coast a gentle-
man of considerable scientific attainments and a first-class practical chemist and
metallurgist. It may be proper to state further, that this gentleman, whose
opinions on this subject of fuel should have much weight, is also professor of
chemistry at the most famous college on this coast, and superintendent at the
assaying and refining works of Kellogg, Hueston & Co., the most extensive
private establishment in that business in the United States.

These works put up by this gentleman at Antioch consisted of a reverberatory
furnace and roasting kiln, built on the plan of those in use at Swansea, but on
somewhat smaller scale, and with a slight change in the form of the grate, to
adapt it to the fuel. The furnace has a base of thirteen feet six inches long, by
nine feet four inches wide, with a chimney-stack, for the purpose of creating
sufficient draft and carrying off the fumes, sixty rfive feet high. All these works
were built of the best available materials.

As stated above, this furnace was built as an experiment, chiefly to test the



WEST OF THE KOCKY MOUNTAINS. 161

adaptability of the Mount Diablo coal for smelting purposes to ascertain the
quality and quantity of heat it generates.

It would occupy too much space to enter into any extended details of the
nature of this coal ; but it may be necessary, to make the subject plain to those
who have never paid any attention to the study of such matters, to state that
in a reverberatory furnace the fire in its passage up the chimney strikes the
roof, and is forced down upon the ore by means of a " bridge," built between
it and the burning fuel. In all flames, no matter how generated, there is one
portion more intensely hot than the others. This is called the " reducing flame"
because of its action in reducing ores, under certain conditions, into metals. All
coals, do not produce a flamo of the same nature or length, and the operation of
the reverberatory furnace depends, in a great measure, upon its being so con-
structed that the " bridge " is placed so that the reducing portion of the flame
is caused to strike the ore at the proper point.

After this explanation it will not require any technical or scientific knowl-
edge of the principles of combustion to understand that a furnace to use fuel,
which burns with a short flame and little smoke, requires great modifications in
its construction when it is to be used to burn fuel which produces a long flame
and much smoke. The experiments at Antioch settled this point clearly, if not
satisfactorily, to those interested, and proves, for general information, that fur-
naces built on the plan of those used at Swansea, in which the short-flamed
Welsh coal is used, are not adapted for the use of the long-flamed coals of the
Pacific coast. But the question whether this long-flamed coal could not be
used for smelting purposes, in a suitably constructed furnace, remains still un-
settled Mr. Price states this Mount Diablo coal could be economically used
for that purpose in a properly constructed furnace, but thinks no attempt should
be made to proceed any further than in the conversion of the ores into regulus.
The price of all descriptions of coal being so much higher on this coast than a
better article can be obtained in other countries, the refining of the metal can be
more profitably done in those countries.

It is much to be regretted that the company, which expended nearly $50,000
in making these experiments at Antioch, did not carry them out to a full con-
clusion, by permitting Mr. Price to make such changes in the form of the fur-
nace as his skill and experience inay have suggested. But in California, where
money commands from 18 to 24 per cent, interest, such experiments are not
considered profitable.

The first bar of metal from the Antioch smelting works was received at San
Francisco on the 14th of September, 1863, and created almost as much interest
as the first bar of bullion from Washoe. During the time these works were in
operation they produced about 200 tons of matt, or regulus, of an average of
about 50 per cent., the balance being iron, sulphur, silica, &c. This was obtained
from about 2,000 tons of ores from various parts of the State, but chiefly from Cop-
peropolis, of an average of about 10 per cent., which the company advertised to
purchase at the following prices :

7J per cent $15 per ton of 2,376 pounds.

9 per cent 17 per ton of 2,376 pounds.

10 ' per cent : . 19 per ton of 2,376 pounds.

11 per cent 21 per ton of 2,376 pounds.

12 per cent 25 per ton of 2,376 pounds.

None were accepted below 7j per cent.

The coal used in the operations cost about $7 per ton delivered on the grounds
of the company. One ton of thia coal, it was estimated, would reduce two tons
of ore, after the furnace had become thoroughly heated ; but in consequence
of the difficulty in obtaining good materials for lining it the furnace was not
kept steadily heated. The best imported fire-bricks, in consequence of the ac-
H. Ex. Doc. 29 11



162 RESOURCES OF STATES AND TERRITORIES

tion of the sulphur in the ore, would not endure more than about fifteen days.
Work had consequently to be stopped within that period, and everything cooled
off, in order to re-line the furnace. This entailed a great loss in the cost of fuel
and labor, as well as of metal, and as the works were only calculated to opeiv
ate on about eight tons of ore in twenty-four hours, these stoppages absorbed
all the profits.

A Mr. Henry Davis, another practical Welsh copper smelter, who had been in
charge of an extensive smelting establishment in Chili previous* to his arrival on
this coast, has made a number of experiments at the works at Antioch since
they were closed by the original owners. This gentleman also expresses the
opinion that the Mount Diablo coal, used in a properly constructed furnace,
oculd be profitably employed in the reduction to regulus of such ores as will not
pay to ship in bulk.

The smelting works erected at the Union mine, at Copperopolis, are on a more
extended scale than those at Antioch. They cost nearly $75,000, and consist of
two cupola blast furnaces, and other buildings, which were erected under the
superintendence of M. Desermeaux, a French engineer, on the plans introduced
on this coast by M. D'Heirry, a very skilful French metallurgist, who has
erected similar works on the Queen of Bronze mine, in Oregon. The whole estab-
lishment consists of four large kilns for roasting the ores to deprive them of a portion
of their sulphur, two large blast furnaces on the most approved German plan, with
a powerful blast set in motion by a 20-horse power steam engine. The kilns are
each capable of roasting 500 tons of oie at a batch, which required from 7 to 12
weeks to burn, according to the weather and the care taken in laying them.
After burning in these kilns the ore was placed in the blast furnaces, which are
capable of operating on eight tons of such materials, each, in twenty-four hours.
The only flux used in any of the operations was a portion of the slag from pre-
vious meltings, or silica in the form of quartz. The ore came from the furnaces,
after the first operation in them, in the form of two qualities of regulus, the one
containing about 80 per cent, of copper, the other about 40 per cent. This
regulus was afterwards broken up and re-melted three or four times, in order to
deprive it of all the sulphur, and to oxidize the iron as much as possible. No
attempts were made to refine this matt into tough copper. The costs for fuel in
these operations were exceedingly heavy, as charcoal, costing from 37 to 50
cents per bushel, had to be used This, together with the necessity for hand-
ling the materials so many times by expensive and unskilful laborers, rendered
the operations so unprofitable that the works were discontinued after a few
months' trial not before some 5,000 tons of ores, averaging about 8 per cent.,
had been converted into regulus, which sold from $200 to $250 per ton, show-
ing that these waste ores may be rendered valuable if they can be operated
upon by some cheap process.

The smelting works at the Cosmopolitan mine, at Genesee valley, Plumas
county, cost about $30,000. These are constructed on the plan described by
Piggott, in his work on copper, somewhat modified by Mr. J. C. Chapman, one
of the proprietors of the mine, under whose directions the works were built.
The blast here is generated by two double-action piston bellows, four feet in
diameter, set in motion by a large water-wheel. No ores have been operated
on at this place except oxides, carbonates and silicates, and as long as plenty of
such ores were attainable, this company was able to obtain respectable
quantities of good matt and inferior copper ; but when the supply ceased, they
had to close up their establishment, as it was not adapted to operate on sul-
phurets.

At these works the molten materials were not drawn off into rough bars and
reinelted, as at Copperopolis, but they were run into a sort of cauldron built in
front of the furnace, in which they were kept sufficiently liquid to allow the
copper to fall to the bottom by its superior specific gravity ; and as the slag,



WEST OF THE ROCKY MOUNTAINS. 163

being the lightest, floated on the surface and cooled 'quickest, it was scraped
off and thrown away; the copper, on cooling, readily separating from the reg-
ulus which was allowed to cool above it. The latter was remelted and the
former was ready for market. The fuel used at these works was pine wood
charcoal, costing about thirty-seven cents per bushel.

Other smelting works, of a novel and very economical and useful character, have
been erected on the La Victoire mine, at Hunter's valley, Mariposa county ; at
the Buchanan mine, in Merced county; at the Campo Seco mine, in Calaveras
county, and at several other mines in various portions of the coast, on a plan
introduced by Mr. Nathaniel Haskell, a California mechanic, and called by him
the " water-lined cupola furnace." These furnaces are capable of reducing
twenty tons of oxides, carbonates, or silicates to good regulus in twenty -four
hours.

The peculiar feature of this useful invention is a " water lining/' which may
be described by stating that the cupola consists of two parts, one within the
other, like the divisions of an onion. These parts are formed of stout iron boiler
plates, strongly riveted at the joints. Between the two there is a space of
about six inches ; this is. kept constantly filled with cool 1 water, by means of a
tank above. This cool water saves an immense quantity of heat that would
otherwise be lost by radiation, and, as a matter of course, affects a correspond-
ing saving in fuel. No fire bricks are used in these furnaces, which, besides
being a great saving in the consumption of this costly article, affects an addi-
tional saving by requiring no time, labor, or heat to be lost in replacing these
bricks every few days, as they become destroyed by the heat. A very power-
ful and even blast is kept up in these furnaces by a large cylinder bellows, set
in motion by a small steam-engine. One of these furnaces, used at the Bu-
chanan mine, has produced upwards of 100 tons of good marketable copper during
the past year, which has sold at San Francisco for from $300 to $320 per ton of
2,000 pounds. That at the La Victoire mine, has only recently been put into
operation, but is producing 80 per cent, of regulus at the rate of 24 tons per week.

It may be quite proper to state that these furnaces are not adapted to operate
on ores containing a very large proportion of sulphur, unless they have been
thoroughly calcined, and are combined wilh a large proportion of other ores or
suitable flux. The sulphur has a very damaging effect on the iron of the cupola
when both are heated to the necessary temperature to melt the ore.

These furnaces will be of great benefit to the owners of mines containing large
bodies of oxides, silicates, and carbonates, which* are of too poor a quality to
ship to market in bulk. They are very cheap and portable, the cupola, blast,
engine, and boiler only costing about $3,000, and all combined only weighing
about five tons.

In 1862 a lady, a Mrs. Hall, invented a novel description of furnace for
smelting copper ores, by means of jets of superheated steam being passed into
the cupola during the time the fuel and ore were in an incandescent state. To
the cupola of this furnace was attached an apparatus for condensing the fumes,
previous to their passage into the chimney. This invention was very much
lauded at the time by Colonel Charles Harazthy, in a letter published over his
own name in the papers at San Francisco.

The concentrating works erected by the proprietors of the Keystone mine at
Copperopolis are on the principle adopted by some of the large copper mining
establishments in Cornwall, England. The ores in these works are operated
upon by water. The object sought to be obtained is the separation of the
gangue rock by means of the difference in the specific gravity and hardness in
it and the ores. There are conditions in which this process is quite simple,
cheap, and effective. It is so where the ore is contained in a silicious gangue,
or in hard spar, in a locality where there is an abundant supply of free water,
constantly running, and where there are plenty of cheap laborers to be had



164 RESOURCES OF STATES AND TERRITORIES

who understand the details of the operations. But a none of these conditions
exist at Oopparopolis, the experiment, which cost about $50,000, if not an
absolute loss, has been only so far successful as only to be of use, at a very
heavy expense, during a few months in the winter, when the rains fill the com-
pany's reservoirs. And then, in consequence of the ore being free from gangue
rock, and the containing slate, from which it is sought to separate it, being of
nearly the same specific gravity and hardness, it is not possible to save more
than three-fourths of it, at a cost of more than it is worth.

These works have been erected in the best manner and of the best materials,
under the directions of Mr. Pawning and his brother, two thorough, practical
machinists. In the operation of these works the ore is brought between two
heavy iron rollers, where it is crushed as fine as possible, and afterwards led,
by means of an endless belt, on to five "jiggers," or shaking tables, which are
each contained in a large tank of water. The motion of these tables causes all
the lighter particles to float off in the stream of water passing through the tanks
These fine particles are collected in "settlers," dried and saved. The coarser
grains which do not float off are 'retained in sieves arranged beneath the tables,
and are returned to the rollers to be reduced to the proper fineness. The ma-
chinery of this cumbrous contrivance is set in motion by a sixty-five horse-
power steam engine.

Many other companies concentrate their ores, to a slight extent, by the process
described in the description of the Napoleon mine, given in another portion of
this report, with such modifications as the judgment of the parties carrying on
the work may suggest, or the necessities of the case may compel.

The above will probably not be considered a flattering account of the various
processes that have been introduced for concentrating and smelting the copper
ores found on this coast. But the many failures therein recorded are not of a
character to discourage so energetic a people as those of the Pacific coast.

The want of success is in so many instances so clearly traceable to the want of
skill and experience on the part of the operators that it is evident a plan for pro-
fitably working the lowest of these ores will be devised when experience shall
have taught those engaged in the business the defects and advantages of the
various processes now in use.

The few observations contained in this division of the report should be suffi-
cient to convince any reasonable person that the manufacture of refined copper
on this coast, with profit, is an impossibility under the present state of affairs.

In reviewing the above remarks on these processes, it will be observed that
the furnace erected at Antioch was erected as much to test the coal as to smelt
the ore. It was made of only sufficient capacity to operate upon eight tons of
ore in twenty-four hours. This was a serious error and a material source of
loss.

The furnace should have been made of a capacity sufficient to have operated
upon at least ten tons. Twelve or fourteen tons would have been better, as it
requires nearly the same quantity of fuel and the same amount of labor to
operate upon eight tons of ore as it would to operate on ten or twelve tons.

The furnaces at the copper mines in Chili, which are built on the same general
plan, and operate upon ores very similar to those found on this coast; and use a fuel
very much like that used here, are constructed of a capacity to work from twelve
to fourteen tons of ore in the twenty-four hours.

The Chilian copper smelters have no better indigenous coal than is to be
found on this coast. They are compelled to import the greater portion of the
coal used in their works from England. As good an article, and at as low a
price, may be obtained here from Sydney, if it is absolutely necessary to im-
port any coal at all.

In California, in consequence of the absence of readily available quantities
of oxides, carbonates, and silicate ores, and the preponderance of ores contain-



WEST OF THE ROCKY MOUNTAINS. 165

ing a large percentage of .sulphur, smelting will always be more expensive than
it is where a different class of ores are used, because it is necessary to put such
sulphur ores through the preliminary process of roasting, which is costly, slow,
and sometimes causes much loss. The object of this process is to expel the
sulphur, arsenic, antimony, phosphorus, or other deleterious element that the
ore may contain, and to oxidize the iron as much as possible. But if this pro-
.cess be carried too far, or the ore contains a very large proportion of the
sulphuret of iron, or when the heat becomes excessive, a fusion takes place,
which makes the separation of the metal from the sulphur much more difficult.
This action in the roasting process caused the loss of many thousands of dollars
to the proprietors of the Union mine, by requiring the regulus produced at their
smelting works to be roasted three or four times to expel the fused sulphur
from it.

With Sydney coal, which may be landed at San Francisco at $9 per ton,
the reduction of low grade ores to 50 per cent, regulus could be made a very
profitable investment for capital. The necessary works, if erected on sufficient
scale to afford a market for, say, 8 per cent, ores, would give an immense im-
petus to the development of the copper resources of the Pacific coast ; because,
without some such market, all the ores of that standard will be valueless for
many years to come, and they form about seven-eighths of all the ores on this
coast.

To prove that such works would yield a large profit on the capital invested,
the following calculation is here given :

Costs attending the conversion of ten tons of 10 per cent, ore into 45 per
cent, regulus :

Ten tons of ore, at $16 per ton $160 00

Roasting in heaps, at $1 per ton 10 00

Six tons of Sydney coal, at $9 per ton 54 00

Labor of four men 15 00

Incidental expenses 10 00

Total costs. . 249 00



Per contra :
Ten tons of the above ore produced two* and three-quarter tons of

regulus of 45 per cent. This is worth $4 per unit, or. $495 00

Deduct freight and expenses attending export 100 00

Leaving balance 395 00

From this deduct cost of ore and reduction 249 00



There is a clear profit of 146 00



This profit would be fully 20 per cent, larger if one thousand tons of ore
were operated upon.

The Bristol copper mine, in Connecticut, when under the management of Mr.
H. H. Sheldon, the present superintendent of the Keystone mine, at Copper-
opolis, paid a very large revenue to its proprietor from ores that did not exceed
3 per cent, in value, on an average. Such a person, after a reasonable amount
of experience on this coast, will certainly be able to devise a plan by which
ores of three times that value may be worked to a profit.

Among the principal causes of the failure of the smelting works tried on this
coast have been

1st. The uniform character of the ores operated on.

2d. The want of experienced and steady, skilled laborers.

3d. The misconstruction of the furnaces.



166 RESOURCES OF STATES AND TERRITORIES

At Swansea the smelters have the advantage of purchasing ores of all or
any classes, as all are brought there from many different districts. With
this assortment of ores at their command, they can arrange the charges of their
furnaces to suit their fuel. On this coast there are no established means for
obtaining such a wide selection of ores as will admit of their being combined so
as to be worked with advantage. Most of the smelting works which have been
tried on this coast operate on the ores from generally the one mine on which
they were erected, and these are generally of one class.

The furnaces built on this coast have generally been copies of such as are
used in England, Germany, or France, where fuel of a totally different char-
acter is used. The impatience of the parties interested in such works to obtain



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