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Page: of 474
146 Ghe BHlining and Scientific Bress,
yein, has ruined, financially, thousands, and will rnin
more before the public will recognize the difference
between the rule and the exception, in mining enterprises. . Be :
There are thonsands of veins in the country that
will pay handsome retnrns upon the proper amount
of capital and labor being expended upvun them. But
if the proper bounds are not regarded, rnin must be
the inevitable result. This is ascertain as the fact
that no vessel can-carry more-freight than. its tonage
measurement, without the risk of going to the bottom.
I have written this article for the purpose of pointing out a road of safety for those who are capable of
measnring the future by tbe experiences of the
present and past history of mining.
J. BE. Cravron, M. &.
[Written for the Mining and ScientiNe Press]
HINTS TO PROSPECTORS.
BY J. GH. CHURCHILL, A. M.
(CONTINUED FROM PAGE ONE HUNDRED AND THIRTEEN.)
V. Prospecting must be nudertaken, more or less,
as scientifie experimenting—a definite question must
be put to mother eartb, at every opening made into
her bowels, and a definite answer obtained from
every rap of the pick. It is not only, “Shall I find
mineral?” It should be mucb more exact—‘ Shall
I find gold, silver or other ores?” according to the
indieations from the surface aud bedrock in its geologieal order. Sinking furtber, “Shall I find the
tmiserals from which the croppings were decomposed ?”—e.er., pyrites where carbonate of eopper has
been abundant. “ Shall I find it rich?” where at the
eroppings a cross-conrse has run into the lead.
“ How shall I find the dip ?”—* how shall I find the
direction of the heave of my lead?” in case of a fault.
“ Wow shall Tidentify my bed of coal?” where the dip
and strike and casing are the only guide. Answers to such qnestions must be insisted upon. If
such qnestions are systematically put with proper
judgment, work to determine them will not be abundoned before the object to be sought is known to be
there or not. Vast labor has been thrown away in
idle guessing.
‘Vi. It mains to show how to learn the value of
your ove. Hixacr Sampuine is the essential preliminary to Exacr Assayine. For tbe first, any method
of wising materials of different sizes, whicb admits of
rolling of the large particles over the smaller, will
be fallacious. Sieves or rakes are necessary to sort
the sizes ; but they eannot do this completely. Rolling must be provided against by laying ont tbe material, after sifting into different coarsenesses, in layers
ona level smooth surface, of a thickness say twice
that of the mesh of the sieve last used, then divided
into portions, and then cleaned up. ‘The exactness
of the work must then be verified by deertmining
whether the specific gravity of the different portions
is the same in that equal medsures are of the same
weight. Thisis to be done readily by weighing
equal-sized boxes or measures one against the other.
This mode of sampling should leave no donbt, and is
simple in practice. One error must be guarded
against. As nearly perfect as this system of sampling is, through une operation, it secures no similar.
ity between equal measures of ore of the same
weight obtained at different samplings. ‘he ore
which does not pass throngh each sieve shonld be
sampled, after sifting, and the sample reduced in size
till it will pass through the sieve, and then mixed
and resampled with the smaller ore.
[TRE END OF SERIES 1.)
eee the Table, page 35, Tor ‘South Wales" read North
ales.
Burning, Roastinc anp Smevtine Ores.—J. D.
Whelply, of Boston, Mass., has patented a process
and arrangement for roasting and smelting ores. In
the process of roasting, water is made to perform a
eonspicuons part. ‘lhe description, in the Official
Patent office Report is merely tecbnical, with reference by letters to drawings, etc., which cannot be
understood in the absence of the drawings referred
to. Ifthe invention is valnable anywbere, it must
be especially so on the Pacific coast. We should
be pleased to hear from the inventor.
[Written for the Mlulng and Scientific Press.]
Sierra District--Humboldt County, N. T.
We have been furnished with a receut communication to the Tallnlah Mining Company, written by
Hon. James A. Banks, Superintendent of the mine,
which is situated near tbe town of Dunglen, in the
niiueral distriet of Sierra, Humboldt county, N. T.,
and which was hriefly alluded to in the columns of
this paper some weeks ago. The well-known ability
and integrity of Mr. Banks, warrants us in asking for
the portions of this communication, which we subjoin, the careful atteation of ourreaders. The Tal.
lulah is a representative mine, and is owned principally by wealthy merchants and lawyers in San
Francisco, who will not part with their interests and
care very little for the fluctuations of the market.
This mine has been opened to a great depth, and the
value of the facts and opinions stated hy My. Banks,
after the most exhaustive aud careful investigation,
lies principally in their vindication of the importance
of Sierra District and of the permanence of its
mines. We append extracts as follows :
Doxeuen, January 26th, 1864.
Weare gradually, and I thiuk certainly, getting
clear of the burnt quartz, to which 1 alluded in previous letters. although the fissnre is still to be seen
in part of the ledge. Having just struck a kind of
ore different froin any I have sent you, I forwnrd
some of it by express. The kind I allude to is that
whicb somewhat resembles black lead in appearance.
Some of the other ore in the package is, in slight
particulars, different from any . have previously sent.
1 consider these specimens rich, but, in estimating
their value, an assay will be worth much more than
my opinion. The ledge shows more silver ore than
it has done at any other poiut iu our progress in the
iucline, which is thirty feet deep. [This iucline was
commenced twenty-five feet to the south of where
the vein was first tapped by the tunnel, at a depth of
two hundred and fifty feet from the surface,. The
ledge is upwards of three feet in thickness. In the
place where the quartz was nost burnt, it narrowed
dowu to about eighteen inches; but that was only
lor a short distance. At that point, the wall rock,
as is usual in such cases, was quite hard. ‘Throughont all that portion of the ledge exposed tv view, it
is admirably defined, uniform in its position and in
its course, running north and south, and pitching
west. ‘I'be walls are perfect, and the seams of clay
separating them from the ledge are never wanting.
The wall rock is porpbyry. ‘lhe shale formations in
the vicinity generally pitcb to the east; and, so lar
as it has any stratification, the graywack pitches in
the sanie direction. Of course in the porphyry we
find nothing that can properly be called a stratification.
J need not say to the members of the Board that
these facts indicate clearly that this is one of those
much valued depositories of the precious metuls,
called “ fissure veins "—the non-existence of which
in this section profound blockheads (whose arrogance and pretension are equalled only by their miseonception and ignorance of ihe docad gevlogy of the
district) have made such a mystifying display of
learning to prove.
In addition to the fact Ihave stated, there are
numerous other evidences in favor of the belief that
this is a regular fissure vein, while there is uot even
a solitary fact that appearto be incompatible with
this view. Nor need . call the attention of the gentlemen, whose reading has heen recent, to the consideration that the geological formation within and
abont the Tallulah claim is the same as that of the
richest and most vefzadle silver mines in the world.
+ e # & * & ES * x #
I wish it distinetly understood tbat [ make no
pretension to that kind of knowledge which enables
sonie men to express the most positive opinion upon
every subject relating to mines and mining; but depending mainly upon that science which lingers
closely around the point of a pick, and having just
completed a careful review of the clatm and df matters connected with it, I feel fully warranted in stating as tme the following propositions—some of
which, it will be observed, are matters of fact, and
some of inference :
1. Neptune Hill has, on every side of it, an immense quantity of quartz boulders of great size,
from which valuable specimens of various kinds of
silver ore have heen, and can be, obtained, although
they are uot nearly so rich as the qnartz recently
struck in the tunnel.
2, These boulders can, in many instances, be
traced to ledges that project above the snrface, while
in other cases the debris covers the croppings.
3. ‘The lode we are now working, and from which
Lhave sent you a considerable number of specimens, which will enable-yon to jndge of its character, contains a large quantity of ore, which can he
profitably worked ; and, as we sink upon it, we will
doubtless find it larger and ricber, especially alter
Preaching the water line. 7
4, The lodes we bave not yet reached will prove
to be both large and rich.
5. The veins we passed through in the tunnel before striking the last, show sufficient mineral, and
are of suflicient size, to warrant the opinion that
they will prove valuable, when followed to a eonsiderable depth; and the Mattie Wayne ledge. below
the mouth of the tunnel, is also a lead of considera‘ble promise, be ng regular and affording some tolerable specimens. It is worthy of remark that these
yeius all run and pitch in the same direction.
6. The vein on which we are now working, while
undoubtedly valuable in itself, is still more important as being indicative of the ebaracter of the otber
veins in Neptune Hill.
7. The topography of the hill is admirably adapted to the thorough and convenient working of the
mine to a great depth.
8. Thesupply of wood within a range of three miles,
is sufficient to render fuel reasonably cheap during
tho next five years, aud the river affords an amplo
power at a distance not excceding six miles over a
good road.
9. The climate is much superior to that of Virginia, Aurova, Silver Mountain or Reese River, and
fresb water springs are very numerous and eusy of
access ; while much of the sickness that prevails
here is clearly attributable to excess aud to earelessness.
10. The development, thus far, of the Tallulah
mine shows it to be exceedingly valnable ; and it is
highly probable, further developments will prove it
to be capable of enriching generations. * * *
When the company determines to erect a mill,
there will be no difficulty in proenring a site, at a
small cost—merely a nominal one, I think. Water
privileges and town sites are too numerous to warrant the spending of mnch time in considering such
propositions as have frequently been presented to me
since my arrival here. * * The company can
ereet a mill bere almost as cheaply us in Virginia
City. With a small expenditure, certainly not exceeding one hundred and twenty-five dollars, I ein
construct a machine that-will cnable me to use timber
found here for nearly everything about a quartz inill,
and being practically, as well as theoretically familiar with the constructing aud erecting of nachinery,
including of course, the making of all necessary
drawings and calculutions, no ex)ensive mechanics
will be required. ‘I'he sending of such niechanies to
distant points to “ boss” the various departments in
the erection of such works, generally involves a
heavy expenditure, and their presence is often the
means of uselessly spending large sums of money.
* * # * * * # %
The best plan is to more thoroughly develop the
the mine, and erect a.small mill, say ol ten stainy:s,
which will not cost a large sum, and with the proceeds
of that, additional works can be constructed without
hurthening the memhers of the company.
In a postscript added on January 27th Mr. Banks
says i—
“Last night we found in the vein a very fine deposit of silver ore, of which I] send yon a large samy le,
This pieceis part of a chunk that weighs wlout seventy-five pounds. * * Wither this is the richest
kind of silver ore, or the books are most outrageously at fault. It seems to he very abundant, althongh
as yet we have had but one blast in it.”
The ore last mentioned by Mr. Bunks, and tested
here by George W. Bell, gave $2,940.60 to the tn ;
the ore he compared to black lead, yielded $2,058.40
and the refuse, after the best specimens were selected, $1,131.00. In each instance the vein rock and
mineral were crnShed together. ‘Iwo hundred grains
of the black metal, unmixed with quartz, yielded
twen'y-eight grains and a fractiou of silver: this is
at the rute of $6,005.63 per ton. ‘Tests have been
made in Virginia City, with similar results, and mill
tests made in Unionville, were almost equally lavorable. The mineral isa double sulphuret of eopper
and silver, containing no gold. Since the letter quoted from was written, the.incliué has been sunk to o
depth of sixty-one ft. below the level of the tunnel, or
three hundred aud eleven feet from the surface of the
ground. Tbe ledge bas gradually increased in size
nutil it is now four feet and a half thick, with tho
black metal so abundantly distributed thronghont it,