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Mark Twain > Roughing It > Chapter XXXVI

Roughing It

Chapter XXXVI


I had already learned how hard and long and dismal a task it is to burrow
down into the bowels of the earth and get out the coveted ore; and now I
learned that the burrowing was only half the work; and that to get the
silver out of the ore was the dreary and laborious other half of it.
We had to turn out at six in the morning and keep at it till dark.
This mill was a six-stamp affair, driven by steam. Six tall, upright
rods of iron, as large as a man's ankle, and heavily shod with a mass of
iron and steel at their lower ends, were framed together like a gate, and
these rose and fell, one after the other, in a ponderous dance, in an
iron box called a "battery." Each of these rods or stamps weighed six
hundred pounds. One of us stood by the battery all day long, breaking up
masses of silver-bearing rock with a sledge and shoveling it into the
battery. The ceaseless dance of the stamps pulverized the rock to
powder, and a stream of water that trickled into the battery turned it to
a creamy paste. The minutest particles were driven through a fine wire
screen which fitted close around the battery, and were washed into great
tubs warmed by super-heated steam--amalgamating pans, they are called.
The mass of pulp in the pans was kept constantly stirred up by revolving
"mullers." A quantity of quicksilver was kept always in the battery, and
this seized some of the liberated gold and silver particles and held on
to them; quicksilver was shaken in a fine shower into the pans, also,
about every half hour, through a buckskin sack. Quantities of coarse
salt and sulphate of copper were added, from time to time to assist the
amalgamation by destroying base metals which coated the gold and silver
and would not let it unite with the quicksilver.

All these tiresome things we had to attend to constantly. Streams of
dirty water flowed always from the pans and were carried off in broad
wooden troughs to the ravine. One would not suppose that atoms of gold
and silver would float on top of six inches of water, but they did; and
in order to catch them, coarse blankets were laid in the troughs, and
little obstructing "riffles" charged with quicksilver were placed here
and there across the troughs also. These riffles had to be cleaned and
the blankets washed out every evening, to get their precious
accumulations--and after all this eternity of trouble one third of the
silver and gold in a ton of rock would find its way to the end of the
troughs in the ravine at last and have to be worked over again some day.
There is nothing so aggravating as silver milling. There never was any
idle time in that mill. There was always something to do. It is a pity
that Adam could not have gone straight out of Eden into a quartz mill, in
order to understand the full force of his doom to "earn his bread by the
sweat of his brow." Every now and then, during the day, we had to scoop
some pulp out of the pans, and tediously "wash" it in a horn spoon--wash
it little by little over the edge till at last nothing was left but some
little dull globules of quicksilver in the bottom. If they were soft and
yielding, the pan needed some salt or some sulphate of copper or some
other chemical rubbish to assist digestion; if they were crisp to the
touch and would retain a dint, they were freighted with all the silver
and gold they could seize and hold, and consequently the pan needed a
fresh charge of quicksilver. When there was nothing else to do, one
could always "screen tailings." That is to say, he could shovel up the
dried sand that had washed down to the ravine through the troughs and
dash it against an upright wire screen to free it from pebbles and
prepare it for working over.

The process of amalgamation differed in the various mills, and this
included changes in style of pans and other machinery, and a great
diversity of opinion existed as to the best in use, but none of the
methods employed, involved the principle of milling ore without
"screening the tailings." Of all recreations in the world, screening
tailings on a hot day, with a long-handled shovel, is the most
undesirable.

At the end of the week the machinery was stopped and we "cleaned up."
That is to say, we got the pulp out of the pans and batteries, and washed
the mud patiently away till nothing was left but the long accumulating
mass of quicksilver, with its imprisoned treasures. This we made into
heavy, compact snow-balls, and piled them up in a bright, luxurious heap
for inspection. Making these snow-balls cost me a fine gold ring--that
and ignorance together; for the quicksilver invaded the ring with the
same facility with which water saturates a sponge--separated its
particles and the ring crumbled to pieces.

We put our pile of quicksilver balls into an iron retort that had a pipe
leading from it to a pail of water, and then applied a roasting heat.
The quicksilver turned to vapor, escaped through the pipe into the pail,
and the water turned it into good wholesome quicksilver again.
Quicksilver is very costly, and they never waste it. On opening the
retort, there was our week's work--a lump of pure white, frosty looking
silver, twice as large as a man's head. Perhaps a fifth of the mass was
gold, but the color of it did not show--would not have shown if two
thirds of it had been gold. We melted it up and made a solid brick of it
by pouring it into an iron brick-mould.

By such a tedious and laborious process were silver bricks obtained.
This mill was but one of many others in operation at the time. The first
one in Nevada was built at Egan Canyon and was a small insignificant
affair and compared most unfavorably with some of the immense
establishments afterwards located at Virginia City and elsewhere.

From our bricks a little corner was chipped off for the "fire-assay"--a
method used to determine the proportions of gold, silver and base metals
in the mass. This is an interesting process. The chip is hammered out
as thin as paper and weighed on scales so fine and sensitive that if you
weigh a two-inch scrap of paper on them and then write your name on the
paper with a course, soft pencil and weigh it again, the scales will take
marked notice of the addition.

Then a little lead (also weighed) is rolled up with the flake of silver
and the two are melted at a great heat in a small vessel called a cupel,
made by compressing bone ashes into a cup-shape in a steel mold. The
base metals oxydize and are absorbed with the lead into the pores of the
cupel. A button or globule of perfectly pure gold and silver is left
behind, and by weighing it and noting the loss, the assayer knows the
proportion of base metal the brick contains. He has to separate the gold
from the silver now. The button is hammered out flat and thin, put in
the furnace and kept some time at a red heat; after cooling it off it is
rolled up like a quill and heated in a glass vessel containing nitric
acid; the acid dissolves the silver and leaves the gold pure and ready to
be weighed on its own merits. Then salt water is poured into the vessel
containing the dissolved silver and the silver returns to palpable form
again and sinks to the bottom. Nothing now remains but to weigh it; then
the proportions of the several metals contained in the brick are known,
and the assayer stamps the value of the brick upon its surface.

The sagacious reader will know now, without being told, that the
speculative miner, in getting a "fire-assay" made of a piece of rock from
his mine (to help him sell the same), was not in the habit of picking out
the least valuable fragment of rock on his dump-pile, but quite the
contrary. I have seen men hunt over a pile of nearly worthless quartz
for an hour, and at last find a little piece as large as a filbert, which
was rich in gold and silver--and this was reserved for a fire-assay! Of
course the fire-assay would demonstrate that a ton of such rock would
yield hundreds of dollars--and on such assays many an utterly worthless
mine was sold.

Assaying was a good business, and so some men engaged in it,
occasionally, who were not strictly scientific and capable. One assayer
got such rich results out of all specimens brought to him that in time he
acquired almost a monopoly of the business. But like all men who achieve
success, he became an object of envy and suspicion. The other assayers
entered into a conspiracy against him, and let some prominent citizens
into the secret in order to show that they meant fairly. Then they broke
a little fragment off a carpenter's grindstone and got a stranger to take
it to the popular scientist and get it assayed. In the course of an hour
the result came--whereby it appeared that a ton of that rock would yield
$1,184.40 in silver and $366.36 in gold!

Due publication of the whole matter was made in the paper, and the
popular assayer left town "between two days."

I will remark, in passing, that I only remained in the milling business
one week. I told my employer I could not stay longer without an advance
in my wages; that I liked quartz milling, indeed was infatuated with it;
that I had never before grown so tenderly attached to an occupation in so
short a time; that nothing, it seemed to me, gave such scope to
intellectual activity as feeding a battery and screening tailings, and
nothing so stimulated the moral attributes as retorting bullion and
washing blankets--still, I felt constrained to ask an increase of salary.
He said he was paying me ten dollars a week, and thought it a good round
sum. How much did I want?

I said about four hundred thousand dollars a month, and board, was about
all I could reasonably ask, considering the hard times.

I was ordered off the premises! And yet, when I look back to those days
and call to mind the exceeding hardness of the labor I performed in that
mill, I only regret that I did not ask him seven hundred thousand.

Shortly after this I began to grow crazy, along with the rest of the
population, about the mysterious and wonderful "cement mine," and to make
preparations to take advantage of any opportunity that might offer to go
and help hunt for it.

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Index Index

Prefactory
Contents
Chapter I
Chapter II
Chapter III
Chapter IV
Chapter V
Chapter VI
Chapter VII
Chapter VIII
Chapter IX
Chapter X
Chapter XI
Chapter XII
Chapter XIII
Chapter XIV
Chapter XV
Chapter XVI
Chapter XVII
Chapter XVIII
Chapter XIX
Chapter XX
Chapter XXI
Chapter XXII
Chapter XXIII
Chapter XXIV
Chapter XXV
Chapter XXVI
Chapter XXVII
Chapter XXVIII
Chapter XXIX
Chapter XXX
Chapter XXXI
Chapter XXXII
Chapter XXXIII
Chapter XXXIV
Chapter XXXV
Chapter XXXVI
Chapter XXXVII
Chapter XXXVIII
Chapter XXXIX
Chapter XL
Chapter XLI
Chapter XLII
Chapter XLIII
Chapter XLIV
Chapter XLV
Chapter XLVI
Chapter XLVII
Chapter XLVIII
Chapter XLIX
Chapter L
Chapter LI
Chapter LII
Chapter LIII
Chapter LIV
Chapter LV
Chapter LVI
Chapter LVII
Chapter LVIII
Chapter LIX
Chapter LX
Chapter LXI
Chapter LXII
Chapter LXIII
Chapter LXIV
Chapter LXV
Chapter LXVI
Chapter LXVII
Chapter LXVIII
Chapter LXIX
Chapter LXX
Chapter LXXI
Chapter LXXII
Chapter LXXIII
Chapter LXXIV
Chapter LXXV
Chapter LXXVI
Chapter LXXVII
Chapter LXXVIII
Chapter LXXIX
Appendix

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