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BANCROFT
LIBRARY

THE LIBRARY

THE UNIVERSITY

OF CALIFORNIA

CI &\

jfi

PRACTICAL
MINING and ASSAYING

FREDERIC MILTON JOHNSON

9. S.

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PRICK
ONE DOLLAR

SAN FRANCISCO

PUBLISHED BY THE AUTHOR

1897

Copyrighted, 1897
by F. M. Johnson.

Idloo?

BANCROFT LIBRARY

0) PREFACE.

D
<

This work is the result of fifteen years of prac-
tical experience in the mountains, the mines, the
mills and the assay office, and is published for
the benefit of the prospector, the miner and
j those who may desire to obtain a general knowl-
O edge of practical mining and assaying.
O I have endeavored to make it as brief and

£- plain as possible for those who have not had the
Q opportunity to acquire the desired information

J on this subject, and this alone has prompted the
publication of this pocket edition of Practical
Mining and Assaying.

Frederic Milton Johnson.

CONTENTS.

Assaying , . . . page 33

Assay for Pure Concentrates 49

Amalgamation 55

Bead Scale 39

Chlorination 59

Cupellation 38

Concentrator 53

Chemical Assay for Gold 27

Dressings for Different Ores 44

Dressing the Plates 56

Formation 11

Fluxes 41

Glossary 99

How to Keep Mercury 56

Introduction 7

Leveling Instrument 65

Measuring Inaccessible Distance 62

Measuring Inaccessible Distance, (with in-
strument) 67

Metals that are Dissolved in Acids 49

Milling Test for Free Gold 26

Mining Laws 90

Ores (see rocks)

Panning for Gold 32

Parting 38

Preface 3

Pulp Scale 35

Rocks 12

Sundry Items 68

b PRACTICAL MINING

Tables, Assay Table, (240 grains) 73

Assay Table, (20 grammes) 76

Cast Iron Pipe 83

Natural Sines 84

Pelton Water Wheel 89

Relative Value of Weights 81

Specific Gravity, Weight and Melt-
ing Point 80

Wrought Iron Pipe 82

Test for Arsenic 31

Black Zinc Blende 20

Fluorspar 30

Gold 26

Gold (with gunpowder) 28

Iron 26

Gypsum (heavy spar) 31

Lime and the Carbonates 30

Lime, Magnesia and Barita 31

Manganese 29

Mercury (cinnabar) 30

Nickel 25

Nitrates (chilly nitre, etc.) 32

Red Copper 29

Silver 24

Tellurium 31

Zinc 29

Testing Ores with Acids 50

Veins or Lodes 21

Weighing 40

Wet Assay 25

INTRODUCTION.

Carbon is the base of the vegetable and organ-
ized world, and quartz or silica is the chief or
principal of the mineral world. A particle of
any one substance is a unit or simple. There are
64 simple substances known. Those that are un-
known are termed elements, which have a tend-
ency to combine with know substances or other
elements, forming compounds with the different
substances under various conditions of tempera-
ture, pressure, electricity, etc. All may assume
either a liquid, solid or gaseous state. These
elements may be mixed in any proportion, but
they combine only in fixed proportions. Chem-
istry gives us the knowledge of the proportions
in which the different substances combine. A
general idea only of such knowledge necessary
for this work is given. The mixture of all
metals by fusion forms alloys, hydrogen, oxygen,
chlorine, bromine, sulphur, arsenic, phosphorus,
silicon, etc., with the different metals enter into
the various compositions of ores and fluxes,
which to a certain extent the assayer must
understand.

A test of ore is made with acids or heat, usu-
ally with a blow pipe, with an indefinite amount

8 PRACTICAL MINING

of ore, simply to determine whether the ore con-
tains gold or silver or the metals sought for.
Testing may precede assaying to enable one to
know what fluxes are best adapted for a correct
assay.

Assays are made by wet or dry processes, i. e.,
acids and chemicals or heat with the proper
fluxes and with a definite quantity of ore to de-
termine the exact amount of metals it contains
per ton of ore. Lead combined with oxygen in
the exact proportion of 103^ parts of lead by
weight to 8 parts by weight of oxygen to form
litharge, this being a flux for most classes of ores
carrying precious metals. The melted lead gath-
ers up the precious metals and is thrown down
by carbon which is a reducer, forming a lead
button in the bottom of the crucible. Under
heat the affinity of carbon for oxygen is greater
than that of lead for oxygen. Therefore if lith-
arge and carbon are heated together the carbon
takes the oxygen from the litharge and the lead
is set free and goes to the bottom as stated
above. One grain of charcoal reduces 30 grains
of lead from litharge. Flour contains carbon and
hydrogen, also oxygen and nitrogen and conse-
quently is a reducer, but one grain of flour will
only throw down 14 grains of lead. Hence
double the amount of flour must be used in an

PRACTICAL ASSAYING 9

assay. I prefer the flour for assaying because it
is more convenient to procure and is cleaner and
in a finer powder.

Nitre consists of nitrogen, oxygen and potas-
sium, and when heated gives off its oxygen.
When sulphur is present, the oxygen combines
with it, and the sulphur is carried off, because
the affinity is stronger for the sulphur, so that
nitre is used in the assay of sulphurets to carry
off the sulphur, melted lead having a strong affin-
ity for oxygen which it takes from the air,
when the door^ or opening to the muffle is
open to admit it and the lead is oxydized and
part of it goes off in fumes and part is absorbed
by the bone-ash of which the cupel is composed.
Gold and silver do not combine with oxygen,
hence when the lead button is cupelled, the gold
and silver remain.

FORMATION.

This question is of the utmost importance and
requires considerable study, but a general idea
may be given to help the miner or prospector
in his search for gold, and requires a technical
knowledge of mineralogy. By technical miner-
alogy I mean only that amount of mineralogical
knowledge which will enable the prospector to
recognize the valuable minerals and metals and
to trace them by the formation in which they are
most likely to be found. This forms but a small
part of the whole subject of mineralogy as a sci-
ence. It is therefore important that the prospec-
tor should be able to distinguish many kinds of
rocks, to guide him or to check him in his ex-
ploration.

The formations forming the gold belts are en-
tirely different in different countries or districts,
hence the knowledge of the formation in Oregon
or Arizona will not assist the prospector in Cal-
ifornia or any other territory except in a very
general way. A man may be an expert on the
Mother Lode in California and know nothing of
the formation in Colorado. One thing, however,
may be settled for any country or district, and
that is where veins, lodes, or vein matter is

12 PRACTICAL MINING

found in a contact or fissure, i. e., a vein between
adjacent bodies of dissimilar rock, where gold is
found in these formations it is the very best evi-
dence of the existence of a permanent ledge, and
the prospector can begin his development with a
certain degree of certainty.

ROCKS.

Rocks may be classed in four great groups,
described as follows: Superficial rocks, Sedi-
mentary rocks, Igneous rocks and Metamorphic
rocks.

First — The Superficial Rocks. These are
composed chiefly of clay, sand and gravel and
lie in irregular beds and unconsolidated.

Second — Sedimentary Rocks. These are
conglomerate sandstone, shale and limestone
which have been deposited by the water and
have usually become hard.

Third — Igneous Rocks. These are rocks
which have been thrown up from a molten con-
dition through crevices and fissures and cooled
where they have formed dikes and veins. Some-
times they pour out of cracks and volcanoes and
flow over the surface as lava and afterwards be-
come scattered and broken up by water and

PRACTICAL ASSAYING 13

streams. The most abundant of these are gran-
itic, grano-diorite, granite -porphyry, diabase,
basalt, augite-porphyrite, augite-andesites and
hornblende.

Fourth — Mktamorphic Rocks. These are
altered rocks of crystalline texture and have
been so changed by pressure and chemical action
that the mineral particles in many^ases re-crys-
tallize and are understood as metamorphic, crys-
talline formations.

We will now give the names and a brief des-
cription of some of these rocks.

Allybydenum is a sulphide in masses. Has a
strong metallic lustre. Color, dead grey. Shows
a greenish black streak on a common piece of
broken plate or china. Easily scratched with a
nail. Occurs in granite, syenite and chlorite
schists. Sometimes mistaken for graphite. Its
chief use is for the manufacture of blue colors.
Value, $12 per pound.

Andesite. — An effusive, porphyritic rock.
The constituents are lime, spar, magnesia and
silica.

Antimony. — Resembles galena in color but is
crystalline in form and when pure looks like a
mass of needle points melted together. Very
often galena and antimony are combined, espe-

14 PRACTICAL MINING

cially in gold and silver ores. This metal mixed
or combined with galena often destroys the
value of a lead mine, and vice versa.

AugiTE. — A dark green or blackish, composed
of iron, schists, and magnesia; lustre vitreous;
found chiefly in volcanic rock.

Basalt.— 40 to 50 % of silica, 15 to 30 % of
alumina, and oxide of iron, manganese, lime,
and magnesia. Color is black, bluish or greenish
shades when broken, usually drab or greyish
brown on the surface.

Bird's Eye Porphyry is composed of feldspar
and specks of hornblende and mica through the
rock in such a manner as to form little specks
resembling birds' eyes.

Casseterite or Tin Ore. — Tin ore is usually
an oxide and contains small quantities of iron,
copper, manganese, arsenic and silica and rarely
any lime. The ore is nearly as hard as quartz and
will scratch glass. It is of a dark brown color,
sometimes almost black; when scratched with a
file or knife, the mark turns brown or light
brown. Zinc does the same when found in other
ores. These are the only metals that the fine
powder made with a file turns brown. It is usu-
ally found in granite, quartzite, metamorphic
sandstone and slaty rock; often traced with black

PRACTICAL ASSAYING 15

tourmaline. It is sometimes found with other
ores as the sulphide of tin with iron and copper.
Looks like bell metal or black oxide of tin. It
is found in granite only when the granite con-
tains chiefly mica and quartz or mica and soda
feldspar.

Copper Glance. — Similar to the above in
character but carries a much larger per cent, of
copper. The fine glance carries about one-third
metal. Found in copper ores.

Diabase. — An intrusive or effusive granular
rock composed of augite, partly or wholly con-
verted into fibrous hornblende, soda, lime and
feldspar.

Diorite. — A granular intrusive rock com-
posed piincipally of soda-lime, feldspar and
hornblende.

Feldspar is silicate of potash amd alumina;
silica and lime.

Gabbro. — A granular intrusive rock consisting
principally of dialage, pyroxene, together with
soda, lime and feldspar.

Gabbro-diorite. — This term has been used
where the gabbro areas contain primary and
secondary hornblende.

Galena. — Bright lead color having a metallic
lustre and when not mixed with antimony,

16 PRACTICAL MINING

breaks in cubes; carries silver and gold; very
often found in gold ores.

Granite. — A term descriptive of rocks com-
posed of silica, feldspar and mica. There are
different classes of granite, nor are they alike in
color. Some granites contain no mica as in
graphic granite. Others contain black mica
stained with iron, and hornblende.

Grano-diorite. — This is also an intrusive
rock carrying feldspar, quartz, biatlte, horn-
blende and mica.

Graphite or Plumbago or Black Lead. -
Soft and soils the fingers; marks on paper; color,
gray to dark blue, nearly black. Found chiefly
in crystalline limestone and mica schists or
graphite schists.

Gypsum. — Composed of sulphuric acid, lime
and water. When it is pure white it is called
alabaster; when transparent, selenite; when
fibrous, satin spar; and when burnt, forms
plaster of Paris. t

Hornblende.— Contains dark or black crys-
talline specks or crystals consisting essentially of
silica, magnesia, lime and iron.

Itacolumite. — A quartzose rock that is more
or less cemented by mica; takes its name from a
mountain in Brazil. Diamonds and other pre-

PRACTICAL ASSAYING 17

cious stones are found in this and other similar
rocks.

Kaolin. — A peculiar clay, composed of silica,
alumina, pyroxide of iron and water. It is used
in the manufacture of porcelain and china; found
ill granitic formations.

Limonite. — A brown ironstone. Jt is com-
posed of iron, alumina and silex, and sometimes
manganese. Belongs to the iron ores.

Manganese. — It occurs as a black or red ox-
ide, often with red or brown hematite; very
easily pulverized. When dissolved with muriatic
acid, it throws off chlorine gas which can be
easily detected by the smell.

Mica Schist. — This" term is given to those
laminated rocks composed of mica and quartz,
manganese, often black, colored with iron, easily
broken up.

Mispickee. — Often mistaken for brittle silver.
It occurs usually in ores that are regarded as re-
bellious with zinc and other bases. It is simply
composed of arsenide of iron and iron pyrites
and is very brittle.

Micaceous Quartz Rocks. — These are not
very common. Generally found in a granite
formation; sometimes carry gold.

18 PRACTICAL MINING

Porphyry is feldspar, quartzite, talc, mica,
iron, and clay; chiefly feldspar and quartzite.

Porphyritic Granite. — A granite with a
large proportion of porphyritic potash-feldspars.
Color, dark green.

Porphyritic Quartz. — A rock consisting of
quartz, lime, feldspar, and a small amount of
hornblende. Often found in contact or con-
nected with grano-diorite.

Pyroxene. — Lustre vitreous inclining to res-
inous, some pearly. Color green of various
shades verging from white and grayish white to
brown and black. A bi-silicate of lime, magne-
sia, protoxide of iron, protoxide of manganese,
and sometimes potash, soda and oxide of zinc.
Usually two of these bases are present. The
first three are the most common but lime is al-
ways present and in a large percentage.

' Quartz or Silica is combined with nearly
every other kind of rock. The miner must
study it carefully, as nearly all the gold is found
connected with it in some way. A few general
ideas may be given to assist the prospector.

When found in ledges or loads in granite
walls, it is flinty and white when pure, but it is
nearly always stained with iron and often car-

PRACTICAL ASSAYING 19

ries iron pyrites. It breaks in chunks like sand
and granite rocks, and when gold bearing, the
gold is found in pockets or bunches and not
evenly distributed through the rock as it is found
in other formations. Sometimes laminated or
stringer quartz is found in granite that carries
the gold principally in the seams. When found
in a contact vein or "true fissure" it is of a more
even texture, carries lime and spar and is much
the better class of ore. When gold or pay ore is
found, it is more evenly distributed through the
quartz when found in contact of slate and por-
phyry. It carries enough oxide of manganese or
slate to give a bluish cast, and is more stratified.
Often carries iron pyrites and galena, and when
galena or copper stain is found in the quartz, it
is the best evidence of a permanent ledge of "pay
ore." This class of ore when found in Mexico,
Arizona, Nevada and Southern California, car-
ries silver and often leads into a silver mine be-
low the water line.

Rhyolitk. — It is of the tertiary age. The
essential composition is alkali, quartzose, and
hornblende.

Red Oxide oe Manganese. — Looks like red
ironstone. At first sight might be taken for
cinnabar.

20 PRACTICAL MINING

Serpentine. — A hydrous silicate of magnesia
combined with talc, syenite, and hornblende,
forming rock known in mining regions as "ser-
pentine."

Siderite. — An iron carbonate; about 62 per
cent, of protoxide of iron or nearly 45 per cent,
of pure iron and from 15 to 20 per cent, of man-
ganese. Looks like black ironstone with small
streaks or specks of white. Color, gray to black.

Silver occurs native in various forms usually
branching or leaf-like or in small particles that
resemble leaf lead. It is never found pure; often
carries copper, lead and gold; it is always malle-
able and can easily be distinguished from mis-
pickle by the fact that it can be cut with a knife
and is not brittle. Before the blowpipe it melts
without leaving any oxide or whiteness around
it as does zinc, antimony, bismuth and tin.

Silver Glance. — A metallic silver combined
with iron and copper. Has the appearance of
leaf lead nearly black. Often occurs pure enough
in the ore to be cut with a knife. This is often
connected with copper glance found in rich cop-
per ores with hematite. Usually carries from 20
to 33 per cent, of silver.

Slates. — There are several kinds of these
slates which should be carefully studied. All of

PRACTICAL ASSAYING 21

these slates are sedimentary or water washed dis-
integration and are found as mica slate, horn-
blende slate, clay slate or argillaceous shale and
bituminous shale, plumbago schists and talcose
slate. Sometimes trap rock and trap and blue
limestone are mistaken for slate, but all slates
have cleavage lines and break in planes while
the trap rock breaks irregularly and rough and
rings to the hammer.

Talc — Composed chiefly of silica and magne-
sia, with alumina and iron; color varies from a
greenish, to a yellowish white with a pearly lus-
tre, and is smooth and greasy to the touch, or-
soapy if moistened.

Zinc Blende. — Streaks white to reddish
brown. Color, resin yellow to dark brown or
black. Occurs in rocks of all ages and is often
associated with ores of lead and sometimes those
of iron, copper, tin and silver.

VEINS OR LODES.

The rocks in the Auriferous Belt occur in very
complex associations, but we have to deal prin-
cipally with the granites, slates and schists, and
it is chiefly in these schists that the gold or
quartz veins are found. These "gold belts"

22 PRACTICAL MINING

consist principally of quartzite, mica-schists,
clay, slate and limestone lentils. The trend of
these lodes or belts is generally North-west and
South-east, but the great mass of granite and
igneous rocks have been intruded among these
schists, forming irregular bodies which interrupt
the regular schistose structure, These are of
the group that forms the famous "Mother Lode"
of California.

Converging or wedge veins are numerous and
lie between the divisions of stratified rock, as
granite, clay, slate, etc. They are never very
long and sometimes show a large blowout or
cropping, but are nearly always unreliable, as the
wedge-like space between the wralls must neces-
sarily diminish in depth.

GASH VEINS.

These are found in all sedimentary deposits.'
They are caused by shrinkage of the particular
stratum in which they exist by the underlying
igneous conditions. Ledge matter or mineral
deposits may be found in these veins which
sometimes "go down" to quite a depth and may
be rich, but they are not very long and thin or
pinch out at the ends. Sometimes they are
lapped with another similar vein wThich may con-

PRACTICAL ASSAYING 23

tinue further. A number of these veins may lap
each other and form a number of ledges in one
claim only a few feet apart, but they seldom, if
ever, go down to any great depth or make a
large or permanent mine.

Fissure Vein.— True fissure vein quartz in-
variably shows ribbon-like stringers parallel to
the walls. The most lasting and permanent pay-
ing mines are found in true fissures as well as in
the contact.

Contact Veins. — A quartz ledge or other
vein matter lying between two walls of dissimilar
rock, as slate and porphyry, or granite and dio-
rite, etc.

Cross Veins are transversely fractured fis-
sures of more recent origin. They are often pay-
ing feeders for the mineral deposits of regular
veins.

Blanket Ledges are those that lie nearly
horizontal and are often a break from some per-
manet vein that may be found in slides which
have moved them from their fracture. They are
seldom very large.

Dikes are not veins aud are generally larger
and are chiefly composed of yellow or blue col-
ored feldspathic, finely crystallized, igneous rock,
or porphyry, often carrying gold, but very fine.

24 PRACTICAL MINING

Deposits. — Sometimes quite extensive and
must have been concentrated by alluvial water-
washing, or precipitation of quantities of min-
erals in large cavities or depressions in the bed-
rock. Those of the volatile and condensable
minerals found in these deposits are cinnabar
and sublimations of lead and antimony.

Alluvial Deposits are of placer and gravel,
sometimes rich in gold and platinum.

Quartz Lodes and vein matter often well
defined, and cropping boldly in veins and spurs,
cross-courses and small dikes, with a variety of
heave, shift or slide that are very misleading and
must be carefully studied and examined in order
to determine what relation they bear, if any, to
a contact or "true fissure."

TESTS. -

TEST FOR SILVER.

Powder and boil a small quantity of the ore in
nitric acid; allow to settle and put in a few drops
of muriatic acid when it will immediately form a
white curdle if silver is present. When exposed
to sunlight for a short time, this white curdle
will turn dark. Sometimes the whole solution
is colored with iron; if so, allow it to stand in

PRACTICAL ASSAYING 25

the test tube until the whitish curdle will settle
in the bottom as a precipitate.

TEST FOR SILVER IN COPPER ORES.

Boil in nitric acid as above; allow it to settle.
Put into the solution a polished piece of copper;
If silver is present, it will show on the copper.

WET ASSAY.

Pulverize an ounce of ore finely; place in a
pint dish (agate or porcelain lined) and boil in
four ounces of muriatic acid until the acid has
nearly all evaporated, leaving the mass in a
pasty condition. Add one-half as much sul-
phuric acid and boil and stir for a few minutes.
Then add five times the uuantity of water. Stir
until it nearly boils, then filter the whole. The
copper is now all dissolved and held in solution.
To this solution put in about four square inches
of sheet zinc and allow it to stand until the zinc
has entirely dissolved. All the copper will be
precipitated im the form of a brown or nearly
blacd powder. Filter aud dry when the powder
may be weighed any melted into a button.

TEST FOR NICKEL.

First pulverize one ounce of ore. Boil in 3
ounces of muriatic acid until nearly dry. Add 8

26 PRACTICAL MINING

or 10 ounces of water; stir and boil: Filter and
add to the solution caustic potash until it stops
effervescing. Filter and put the filtrate in a cru-
cible with three parts of soda and one of borax,
and melt. Allow it to cool in the crucible and
find the button in the bottom.

TEST FOR IRON.

Powder and dissolve in muriatic acid in test
tube over the lamp. Allow it to cool and settle.
Add a few drops of ferro-cyanide, when, if iron
is present, it will immediately turn blue.

TESTS FOR GOLD.

Milling Tkst. — This may be satisfactorily
made in the following manner. Break up and
powder the ore to pass through 10 mesh, not less
than one-fourth of a pound; one or two pound
lots are better if your muller or mortar is large
enough. For this purpose a Buck's patent muller
is the best. Now dissolve one ounce of cyanide
and 3 ounces of caustic soda in five gallons of
water; then add one-half teacup-full, no more, of
this solution into the water or muller with the
ore, and half a thimble-full of mercury, then add
one pint of water; grind for half an hour; fill the
mortar nearly full of water, turning slowly for
fifteen minutes. Empty the whole in a pan and

PRACTICAL ASSAYING 27

collect the mercury. Be careful to save every
particle. Sometimes it is very hard to collect all
of the mercury. In such cases pour off all the
water and add a little sodium amalgam; shake
for a few minutes, when it will all collect nicely.
In the absence of sodium amalgam use one hand-
ful of dry sand, stirring it thoroughly for a few
minutes, then pan it as usual, when the mercury
will collect. Now dry the mercury with blot-
ting paper, put it in an evaporating dish or any
small dish that will stand heat; cover with two
ounces of nitric acid and boil until all agitation
ceases. The gold, if any, will be found in a
bead-like form at the bottom. Pour off the acid
carefully, rinse with rain or distilled water; dry
over a lamp and weigh. Calculate the weight of
gold at four cents per grain. If one pound of ore
has been used, multiply by 2,000. If one-half
pound of ore, multiply by 4,000, and so on.
This gives tfye value per ton. Follow these di-
rections carefully and the result will give the
exact quantity of free gold.

CHEMICAL ASSAY FOR GOLD.

Take a carefully prepared sample of one ounce
of ore, ground to 60 mesh; put into an enameled
or porcelain dish with a half teacup-full of nitric
acid; stir and boil until the fumes are steam

28 PRACTICAL MINING

white. Now fill the dish with clear water,
stir and then filter, or carefully pour off the
water; add a little lime or lye with more water to
entirely destroy the acid. Be sure to save all the
pulp, filter or pour off the water again; rinse all
the pulp into an earthen bowl; now add a few
drops of mercury and grind with a pestle or the
bottom of a long bottle for half an hour, save the
mercury and retort with acid as in the mill test.
Weigh and multiply by 32,000; the result will be
the value of a ton of ore. The gold from this
test must be weighed on the bead scales. One
bead point on the scale with one-tenth of a grain
rider is equal to $12.56 per ton of ore.

A TEST FOR GOLD.

A simple test for gold may be made by first
pounding the rock to a fine pulp and mixing
with it twice the quantity of common gun-
powder and water into the constituency of thick
mortar. Press it into the form of a brick or ball
and let it dry. When thoroughly dry place it on
a shovel or flat rock, cover with a few chips and
set fire to it. When the fire goes out, rake
through the ashes or pan them, and you will
find a gold button if there is any in the ore.
This test will not succeed if the ore carries much
iron pyrites or other base metals.

PRACTICAL ASSAYING 29

TEST FOR MANGANESE.

A very interesting test for manganese is made
as follows. Take the ore supposed to contain
manganese and powder a little very fine and dis-
solve it in muriatic acid over a gentle heat; then
let it cool and settle. This solution will be col-
ored brown. Now dissolve a little sal soda,
(common washing soda), in pure water; then put
a little of the brown solution into a test tube or
saucer, add soda solution, when it will instantly
become clear and nearly water- white, if mangan-
ese is present. If curdled and dark or cloudy, it
is iron, and not manganese.

TEST FOR RED COPPER.

Very brittle; does not froth with acid, but is
dissolved in ammonia and turns blue in a few
minutes. Also the carbonates of copper will
turn blue when dissolved in ammonia.

TEST FOR ZINC.

Powder the ore and throw on live coals.
Shows a brilliant white flame. Moisten a piece
of charcoal with a solution of cobalt nitrate. Put
some of the powdered ore on the moistened char-
coal and heat with a blow pipe or over the forge,
when it will turn to a deep green.

30 PRACTICAL MINING

BLACK ZINC BLENDE.

Is sometimes found so pure that it is mistaken

for galena. The infallible test is that when

scratched with a knife the powder of galena

turns black whilst that of the blende turns brown.

TEST FOR FLUORSPAR.
Is composed of fluoric acid and lime. Throw
a piece in a hot fire on a forge, when it will fly
and crack in pieces. The pieces of the pure
fluorspar after a strong heat will show a phos-
phorescent light some little time after being
taken from the fire. Once seen will always be
remembered.

TEST FOR LIME AND THE CARBONATES.

After heating to nearly a white heat, will slack
in water and when powdered produces a some-
what violent effervescence in acids.

TEST FOR MERCURY.— (CINNABAR.)

Powder the ore, mix one or two grains with
equal parts of soda, and place in the bottom of
the test tube. Take a small thin piece of copper
or brass about two inches long or a little gold-
leaf; (the gold leaf must be wrapped around a
thin piece of wire.) Place the copper inside the
test tube using a cork to hold it in place — one

PRACTICAL ASSAYING 31

inch of the copper extending below the cork.
Gently heat over a lamp until nearly red and
allow it to cool If mercury is present it will
show on the copper, brass or gold, whichever
may be used.

TEST FOR TELLURIUM.
Powder and moisten; heat with blow pipe on a
piece of white porcelain; now moisten the hot
porcelain with sulphuric acid: Leaves a red or
scarlet color.

TEST FOR ARSENIC.

Powder the ore and throw onto coals or heat
on charcoal with a blow pipe. Gives off the
smell of garlic.

TEST FOR LIME, MAGNESIA AND
BARITA.
It cuts or scratches with a knife. Foams or
effervesces with nitric acid. It dissolves with
effervescence in muriatic acid, and if pure, that
is, not mixed with other matter, the solution
will be colorless.

TEST FOR GYPSUM.— (HEAVY SPAR.)

Is scratched with quartz or a knife. Does not
dissolve with acids and has no smell when
heated. When ground finely, it feels like starch.

32 PRACTICAL MINING

TEST FOR NITRATES. — (CHIIJ.Y NI-
TRE, ETC.)

Flashes when thrown on live coals. It will
dissolve in water, and when four parts of this so-
lution and one part of sulphuric acid and one
part of salt are mixed together it will dissolve
gold.

PANNING FOR GOLD.

The prospector and even the practical miner is
almost invariably deceived in the value of gold
he gets from a few pieces of ore in the pan or
horn. In the first place, he will always think
that the piece or pieces of ore he took to sample
or pulverize is not nearly as much as it really is.
He will think he has pounded up about an ounce
when it is nearer three ounces, and should al-
ways weigh the sample before crushing, and then
he may form some reasonable estimate of the
value of ore per ton 'by the amount of gold in the
pan, if he has been careful to have even ounces,
as two or four. Now after he has saved a few
colors they always look to be more than there
really is. Especially if the gold is fine, one may
really think there is $10 per ton when there is
not $5. It takes very many fine particles of
gold to make one cent. To illustrate how very

PRACTICAL ASSAYING 33

fine it can be, one grain of gold is worth four
cents, and this one grain can be hammered into
a leaf of gold containing 75 square inches.

One 50, 700th part of one grain can be seen by
the eye, and gold is found in talcose slate so
very fine that it would take enough of these par-
ticles to cover four inches square to make one
cent, so unless the gold is coarse, one may easily
be deceived as to the amount or value of gold in
a ton of ore, if you will carefully pan the gold
from i pound of ore and then collect it with
mercury, as in the mill test given on page 26;
then the gold can be weighed and calculated
with some degree of certainty.

ASSAYING.

This work is not intended for those who wish
to fit up an assay office for a permanent business,
in which case they would require a full and com-
plete laboratory. I will endeavor to describe and
explain how to make satisfactory assays and prac-
tical tests on the ground, at the mine, or over
the forge. An outfit for the assay er may be
very elaborate and expensive but for the purpose
of this work only the few implements actually
necessary are mentioned. First, a small port-
able carbon or coke furnace. It can be bought
for $12 or $15. In a coal furnace the muffle will

34 PRACTICAL MINING

'be included. With the carbon furnace it will be
necessary to have a muffle furnace separate.
This muffle furnace will cost about $23, but for
the many who may not possess either of these,
satisfactory assays may be made with an ordi-
nary blacksmith's forge. Nearly everything re-
quired for practical tests and assays may be had
at almost every small town, or may be carried in
a gripsack. The only expensive things required
are the scales for weighing the prills or beads.
There are small pocket scales that will answer
every purpose, and can be bought for $12, but if
one has no scales, the prills or beads from the
assay and the gold from the mill test must be
saved in small bottles, and numbered, to be
weighed when convenient.

For assaying one must have crucibles to hold 8
ounces. I use No. 9 Denver; they cost 8 cents
each. (Following is given a list of the more im-
portant things.)

The cupels should be one and one-half inches,
and cost 30 cents a dozen. One-half inch test
tubes 5 inches long. For a drying cup a broken
saucer will answer. Evaporating dishes 3 and 4
inches. These cost 35 cents, and will stand
heat. A muffle costs one dollar.

A substitute for a muffle. — Take a piece of 4
or 5 inch iron pipe or an old mercury flask or a

PRACTICAL ASSAYING 35

crucible; any one of these will answer the pur-
pose. A mortar. — A good substitute for a mor-
tar is a piece of 2 or 3 inch gas pipe 8 inches
long. For a pestle any old steel drill. Sieves
63 mesh and 10 mesh. One pair of small pulp
scales to weigh the ore; any scales that will
weigh a half-ounce or more, will answer.

On page 36 is a cut of a pulp scale that any
one can make in an hour, that will answer for
weighing from one-sixteenth of an ounce to two
ounces or more of ore for assaying. A glance at
the cut will show how it is made. A scale bar is
made out of a thin strip of board \ inch wide,
narrowed down at the ends a little, and a needle
put through the middle just above the center line;
piece of tin, 3 inches long and 1 inch wide, more
or less, with the ends bent up square, as shown,
for the needle to rest on; and the cover of a small
tin can be fastened to one end to hold the ore,
and a small bar of lead weighing just two
ounces, bent so as to straddle the bar. Place the
lead weight close to the needle, just so it will
balance the pan at the other end. Mark the bar
at the lead, and divide or rule it from the bal-
ance to the end into 32 lines or divisions, to the
end. Now when the lead weight is at the end
it should balance with 2 ounces of ore in the pan.

PRACTICAL MINING

biO
a

<
O

PRACTICAL ASSAYING 37

A common earthen bowl will do for mixing the
assay, or it may be mixed on a piece of strong
paper with a spatula or ordinay table knife.
One pair of crucible tongs and one pair of cupel
tongs. — These may be made with a piece of
quarter-inch wire three feet long. Flatten the
ends, bending them together. Some of the
smaller blacksmith's tongs will answer. An iron
mould is necessary for pouring the assay into, if
you desire to save the crucible for another assay;
but if you have no mould, remove the crucible
from the fire, jar it lightly to settle the lead and
stand it where it wTill cool and then break and
find the lead button at the bottom which must
be cleaned of all the slag, when it is ready for
the cupel.

If working with a coke or charcoal furnace or
forge, first get a good bed of glowing coals. Set
in the crucibles, hold them in place until the
coal is placed firmly around them. The cru-
cibles must always be covered with the crucible
covers in order to keep everything out. Open
the blast and heat until nearly white. Remove
the cover, and if the slag has quit boiling, looks
smooth and settled, it is ready to pour into the
mould. When nails are used, they must be
taken hold of with the tongs, tapped lightly
against crucible side and removed; then pour.

38 PRACTICAL MINING

CUPELLATION.

Cupels may be made of bone ash together with
the proper moulds, but when a few are wanted it
is preferable to buy them. The proper size is
one and one-half inches for the ordinary assay.
If you have a regular furnace the muffles will be
provided and the work is simple. The cupels
are placed inside the muffle as many as may be
required, and then brought to a red heat
when you take out the tongs and place the lead
button inside the cupel,' carefully noting the po-
sition in order to identify each assay. Close the
muffle and increase the heat to a bright red or
until the lead is well melted, when it is opened a
little to admit air. The lead now appears lumi-
nous; rainbow colors are circling over it. Air
should be admitted at this point to increase the
oxidization.

When the fumes are seen rising from the lead
it must be kept in that condition until the lead
has enterely disappeared, when the cupel is re-
moved and cooled. The prill is then ready to be
weighed and parted.

PARTING.

Silver is soluble in nitric acid. Gold is not,
but the bead to be parted must contain at least
twice as much silver as gold, and should be flat-

PRACTICAL ASSAYING 39

tened to a thin sheet and put in test tube and
boiled in nitric acid until the red fumes cease,
and the acid clears; and the particles of gold, if
any is seen at the bottom, as brown powder.
Now pour off the acid and fill the tube with pure
or distilled water, and rinse once; then fill with
water, and place the dry cup or saucer over the
tube to hold 'the water, and invert the whole,
still holding it firm, allowing the gold to settle
in the cup, and let the water off gradually. Now
dry and weigh the gold. Having first weighed
the bead from the assay subtract the weight of
gold from the weight of the whole bead and you
have the amount of silver and gold in the assay,
unless it is known that the ore contains two or
more parts of silver, to one of gold, a weighed
amount of pure silver should be added to the as-
say in the crucible, and deducted from the bead
weight.

BEAD SCALE.

A cheap and convenient bead scale is shown
on page 41. Take a hard, dry piece of wood 6
inches long and i of an inch thick and $ of an
inch wide in the center and \ of an inch wide
at each end. Bend a small piece of tin, or thin
brass V-shaped, and fasten to the right end as
shown in the cut to hold the weights, and fasten

40 PRACTICAL MINING

to the other end, a piece of tin \ inch square,
made a little cupping to hold the beads. Now
take a piece of li inch wide and 6 inches long
for a base. Fasten onto each side of this base a
piece 3 inches long and £ inch square, on top of
these (see cut.) Fasten a piece of glass tubing
filled nearly full of alcohol corked and sealed, on
top of these pieces with small wire staples, as
shown. These show when the scale is level, and
serve as rests for the ends of the needle, passing
through the scale beam as seen in the cut. This
needle must be put exactly in the middle of scale
bar, and just i of an inch below the top. Use the
regular Troy weights from 10 grain to one-tenth
of a grain, with a one-tenth rider weight to use
on the scale bar which must have the division
lines from the center to right end. Divided into
20 parts with the figures, 1, 2, 3, 4, 5, 6, 7, 8, 9,
on the tenth divisions, the same as the regular
scales, the pan making the tenth.

WEIGHING.

The bead is taken from the cupel, placed in
left hand pan of the scales, as it will be more
convenient to use the weights in the right hand
pan, if you have the proper bead scale, with
riders. The beam is divided into 20 parts,
numbering the tenths, 1, 2, 3, 4, 5, 6, 7, 8, 9,

PRACTICAL ASSAYING

Crq
0>

CO
CO

42 PRACTICAL MINING

the pan making 10. Now if you have taken 240
grains for the assay, and have the Troy weights,
every number, or "tenth, is one one-hundredth
part of a grain and is called a "bead point,*' and
is 1.21 ounces to the ton of 2,000 pounds of ore,
and if gold, $25.12. (See table.)

If you take 291.66 grains of ore for the assay,
every bead point will represent one ounce to the
ton of ore, and if gold, $20.67.

FLUXES.

Lithargk. — A lead oxide, 8 to 10 cents per
pound. It is an oxidizer or desulphurizer; that
is, it oxidizes the iron and destroys the sulphur
and is a source of lead which takes up the gold
and silver in the ores. It is a flux because re-
fractory substances are melted with litharge at a
moderate heat. It fluxes most rocks, earth and
metal oxides. A desulphurizer, because it burns
the sulphur.

Soda. — Common baking soda, 4 cents a
pound. It fluxes quartz and some metal oxides,
desulphurizes galena, antimony and bismuth.

Borax. — 8 cents per pound. Fluxes clay,
lime, magnesia, slate.

Borax Glass. — 65 cents per pound. Fluxes
the same as borax but does not swell. To pre-

PRACTICAL ASSAYING 43

pare it, melt it, allow it to cool in thin pieces
and grind to powder. One part by weight is
equal to two of undried borax.

Glass. — Common bottle or window glass.
Pulverize and grind finely. Used in assays con-
taining much lime, clay, etc., but not quartz.
Useful in an assay where much litharge or nitre
is used to protect the crucible.

Nitre. — 15 cents per pound. A powerful ox-
idizer; destroys the sulphur; will oxidize all met-
als excepting gold and some of the platinum
group.

Sulphur. — Used in certain kinds of assays, as
copper, to prevent the copper entering the lead
button. The copper will be converted into sul-
phurets.

Iron. — (Nails or wire.) A desulphurizer for
galena and silver ores with sulphur, not for sul-
phurets of iron, copper and zinc.

Salt.— Used because it becomes very fluid.
Serves as a cover to exclude air, also to wash the
sides of the crucible.

Sheet Lead. — 25 cents a pound. Tea lead
will answer.

Flour. — A reducer; reduces the litharge into
lead. One part by weight of flour reduces fifteen
parts of lead.

44 PRACTICAL MINING

Charcoal. — A still better reducer than the
above, as it throws down 30 parts of lead by
weight to one part of charcoal.

Acids. — Nitric 40 cents per pound, muriatic
and sulphuric.

Distilled Water. — Filtered rain water will
answer.

Black Flux. — A mixture of charcoal, potas-
sium carbonate; one ounce of powdered charcoal
and 8 ounces pulverized potassiu mcarbonate,
thoroughly mixed and kept dry.

DRESSING FOR DIFFERENT ORES.

It must be remembered that soda is a flux for
quartz and galena, borax for earths and metal
oxides generally, litharge for all. I give a few
samples of dressings for general use. Charcoal
and flour are reducers. Charcoal has double the
strength of flour; either can be used.

Quartz :

Ore One part.

Eitharge Three parts.

Soda. . . .One and one-half parts.

Borax One-half part.

Flour One-eighth part.

or Charcoal. . . .One-twelfth part.
Cover with salt.

PRACTICAL ASSAYING 45

Mix the litharge with the ore first, then mix
all together thoroughly, and after placing in the
crucible cover with the salt. The crucible
should not be more than two- thirds full.

Quartz carrying not more than three per
cent, of sulphurets:

Ore One part.

Litharge Three parts.

Soda One-half part.

Borax One part.

Charcoal One-eighth part.

Cover with borax and salt.

Rock carrying iron pyrites and galena from
two to ten per cent.:

Ore One part.

Litharge Three parts.

Soda One part.

Pearl ash One-half part.

Borax One part.

Charcoal One-eighth part.

Cover with salt with two or three twelvepenny
nails, according to the amount of sulphurets
contained in the ore. The nails are stuck down
through the dressing, heads up. They serve to
throw down the lead and silver and take up the
sulphur.

46 PRACTICAL MINING

Ore carrying galena, copper, zinc and other
bases :

Ore One part.

Litharge Five parts.

Soda Three parts.

'Pearl ash .One part.

Charcoal . . . .One-sixteenth part.
Cover thickly with salt and add three or four
twelvepenny nails.

Silver ores carrying galena:

Ore One part.

Soda Two parts.

Pearl ash One part.

Charcoal .... One-sixteenth part.

Cover with borax.

Quartz rock carrying five to ten per cent, sul-
phurets:

Ore One part.

Litharge Four parts.

Soda One part.

Pearl ash One-half part.

Borax One part.

Charcoal One-tenth part.

Cover with salt and borax mixed.
Ore containing arsenical pyrites or arsenide of
iron, five to twenty per cent.: •

Ore One part.

Soda Two parts.

PRACTICAL ASSAYING 47

Litharge Four parts.

Pearl ash One part.

Charcoal One-twelfth part.

Cover with borax; stick one twelvepenny nail
in the center.

Antimony:

Ore One part.

Soda Four parts.

Cyanide of potassium Two parts.
After charging the crucible, add a few grains
of charcoal.

Galena:

Ore One part.

Soda Four parts.

Pearl ash One part.

Charcoal . . . .One-sixteenth part.

Ordinary ores carrying quartz, clay, lime,
iron, etc. :

Ore One part.

Litharge Three parts.

Soda One-half part.

Pearl ash One-half part.

Borax One part.

Charcoal One- twelfth part.

A little salt to cover, and one-third part of
borax on top.

48 PRACTICAL MINING

For the most refractory ore:

Ore One part.

Litharge Sixteen parts.

Soda Two parts.

Borax-glass One part.

Charcoal One-sixth part.

Salt to cover.

Concentrated pyrites:

Ore One part.

Litharge Eight parts.

Soda ■■". Eight parts.

Glass Four parts.

Lead:

Ore One part.

Soda Four parts.

Borax . One part.

Flour, by weight, One-sixth part.

Bismuth :

Ore One part.

Soda Four parts.

Borax-glass One-half part.

Flour One- twelfth part.

Salt to cover.
Tin:

Ore One part.

Soda Three parts.

Cyanide of potassium Two parts.

PRACTICAL ASSAYING 4CJ

Assay for pure concentrates or ore, an}- very
heavily sulphurated ore or nearly any of the very
base ores:

Take 240 grains of ore or the assay ton of
291.66 grains of ore; pulverize to 60 mesh; mix
thoroughly with double the quantity of nitre,
(salt peter). Put into a crucible so large as not
to more than half fill it. Place in a moderately
hot fire and after complete fusion stir it in the
crucible with a hot iron rod or wire three or four
minutes, then add quickly with a long scoop or
ladle, the flux, it having been prepared before-
hand, as follows: \ ounce of litharge, one ounce
of soda and six grains of finely pulverized char-
coal; and cover the crucible and incease the
heat, when it should melt in fifteen or twenty
minutes. When melted take the crucible and
tap lightly to settle the lead, and let it remain in
the crucible until cool; then break the crucible,
extract and clean the button, cupel and weigh.

METALS THAT ARE DISSOLVED IN ACID.

Nitric acid disssolves silver, copper, iron, bis-
muth, zinc and mercury.

Sulphuric acid dissolves silver, copper, bis-
muth, zinc, tin and antimony.

Hydrochloric or muriatic acid dissolves iron,
zinc, bismuth, and antimony if powdered.

50 " PRACTICAL MINING

One part of nitric acid and two parts muriatic
acid dissolves gold, platinum, copper, iron, silver,
zinc and bismuth; and if diluted with, will dis-
solve lead. Lead is not dissolved in nitric acid,
but will be converted into a white powder.

A solution of caustic potash dissolves zinc, tin,
and aluminum.

A solution of cyanide of potassium dissolves
the following metals out of finely pulverized ore:
gold, silver, zinc, copper, lead and aluminum.
It will act more rapidly when combined with
peroxide of soda.

TESTING ORES WITH ACIDS.

Many very satisfactory tests can be made with
acids with very little trouble, the outfit costing
only a few dollars, and can be carried in a small
chest or even a grip sack, the material actually
necessary consists of the following:

1 lb. C. P. nitric acid.

1 lb. C. P. muriatic acid.

1 lb. sulphuric acid.

-J lb. cyanide of potassium (dry).

1 bottle caustic soda, in sticks (pure).

1 small porcelain-lined dish.

2 small evaporating cups.
\ dozen test tubes.

PRACTICAL ASSAYING 51

1 funnel, some filter paper and some blotting
paper.

1 lb. mercury -and i lb. sodium amalgam.

1 small bottle of ammonia.

\ lb. ferrocyanide; a few thin strips of copper
and zinc.

1 lb. sal soda (common washing soda).

The above outfit will enable one to make the
milling test for free gold, the copper assay and
the chemical tests given in this work, as well as
many qualitative tests for gold, silver, copper,
lead, mercury, iron, bismuth, manganese, anti-
mony and nickel. If the ore contains iron py-
rites, sulphate of copper, arsenic or zinc, it is
well to powder and roast the ore before the acid
is added, but if one ounce or less is taken for the
test, and this powdered to 90 or 100 fine, then
nitric acid will do the work.

Put a little of the powdered ore into a test
tube, or one of the evaporating dishes; if a test
tube is used, take as much ore as will lay on a
ten cent piece. If a dish is used, \ ounce of the
powdered ore may be used. The acid used in
test tube should fill the tube not more than 1^
inches above the ore; if a dish is used 1 ounce
of nitric acid with a very little water may be
added to the ore and heated gently over a lamp
10 or 15 minutes, or until any violent action

52 PRACTICAL MINING

ceases, then let it stand until cool and settled.
Now pour a little of this solution into a test
tube, and add and as much muriatic acid. Now if
the ore carries silver, it will be seen as a whitish
curdle or white precipitate of chloride of silver.
If lead is present, it will be thrown down as a
white precipitate, or powder; mercury will show
the same as silver, but mercury and silver are
not found in the same ore. Now if a precipitate
is found and settled at the bottom, carefully pour
off the clear solution and add a little ammonia to
this precipitate and shake it a little in the tube
and note the result.

If the white precipitate is dissolved, it is sil-
ver. If blackened, it is chloride of mercury. If
it still remains unchanged, it is lead. A test for
antimony is made the same way, dissolving first
in nitric acid, and adding muriatic; let it settle
clear as before and introducing a piece of zinc,
if it is antimony a black precipitate will be seen.
If the ore to be tested carries iron, copper, and
other metals, first thoroughly dissolve the pow-
dered ore in nitric acid by heating; let cool and
settle. Now try a little of this solution in a test
tube, by adding as much dilute sulphuric acid,
white precipitate, shows lead. Add an excess of
ammonia to some of the original solution, and a
blue color shows copper, or nickel.

PRACTICAL ASSAYING 53

Red color shows peroxide of iron. By adding
muriatic acid to this solution, and introducing
the point of a knife, a coating of copper will
form on the blade if copper is present. Again
add an excess of potash to the first solution and
note the reaction. Blue shows the presence of
colbalt; light green of nickel, brown of iron;
white of zinc; yellow of mercury.

CONCENTRATOR.

My improved carpet concentrator (see cut, page
54), is one of the most effective and least expen-
sive used, and does not require power. "A" is
tank 6 feet wide and 16 feet long. In it is
placed a box 29 inches square and 15 feet 5
inches long, hung on gudgeons at each end, to
run in boxes on the outside of, and at the end of
tank "A," as shown in the end view (fig. 2),
allowing it to revolve. This inside box is made
by cutting end pieces out of 2-inch plank ex-
actly 27 inches square. Now nail on one-inch
boards 16 feet long to form the box. Let the
inch board project over the two sides two or
three inches to form a trough or sluice, and nail
strips one by three on the other two sides for the
sluice; now cover these sides, which will be just
27 inches inside the sluice, with Brussels carpet;

PRACTICAL MINING

PRACTICAL ASSAYING OO

the whole is placed below the plates "D" as any
other concentrator, with the same pitch or in-
cline as the copper plates. Now the pulp is car-
ried from the plates to the carpet with a short
moveable apron. Then the pulp flows over the
carpet, and the sulphurets, and heaviest particles
settle in carpet, and are washed off into tank
"A" as the box revolves, in the water in the
tank. Now as the carpet becomes filled with
concentrates a clean side must be turned up.
This may be done every hour or two. The idea
is to keep the carpet free from the gangue, or
nearly so, as nothing catches concentrates better
than clean Brussels carpet, With very little ex-
perience and attention this will do the work.
An apron is placed at the lower end to carry off
the gangue.

AMALGAMATION.

The first and most important point is to thor-
oughly understand the cleaning of the mercury.

First — Retorting of foul mercury. The retort
should not be more than half full, and covered
with a layer of quick-lime or powdered charcoal.
Lute and wedge the cap on the retort. Cover
the pipe with wet rags and allow it to extend to,
but not in the water. Keep water running on
the rags, and commence the heating very gradu-

56 PRACTICAL MINING

ally and slowly until the retort is nearly red.
Stop heating before it is fully red and allow it to
cool. The mercury will be found in the water.

Second — To clean mercury without retorting:
Put the mercury in a fruit jar or large bottle, say
five pounds. To this add one teacup full of nit-
ric acid, three teacups full of distilled wTater.
Allow it to stand for twenty-four hours, shaking
it occasionally.

HOW TO KEEP MERCURY.

It should be kept in a large jar, mug or bot-
tle, preferably a bowl or large mouthed bottle.
Put into the bottle 5 pounds of mercury, one
pound of sal-ammoniac, 2 pounds of quick-lime,
writh just enough water 'to dissolve. Shake it
well. Use the mercury from this jar.

DRESSING THE PLATES.

Rinse them off with af hose, u^ing clean water.
If they are fouled or dark, go over them with a
brush or flannel-mop, washing them with the
following solutions as may be best suited to the
conditions which will be given below.

The best for general purposes is solution

No. 1. — Cyanide of potassium, 2 ozs.
Caustic soda, 5 ozs.

Dissolved in five gallons of water.

PRACTICAL ASSAYING 57

When the plates are fouled or blackened with
black sulphurets, use eithel of the following:

No, 2. — To five gallons of strong brine add
one-half pint of sulphuric acid.

No. 3. — Sal-ammoniac, 1 lb.

Lime, 3 lbs.

Carbonate of soda, \ lb.

Go over the plates thoroughly with one of
these solutions. When the plates are fouled
with zinc, black oxide of manganese, sulphate of
copper, use

No. 4. — Muriatic acid, 1 lb.

Water, 5 gallons.

After having cleaned the plates and used one
of the above solutions, take from the bottle one
pound of mercury, put it in a small bottle and
add one-half ounce of sodium amalgam.

Stretch a piece of muslin over the mouth of
the bottle and sprinkle the plate with the mer-
cury; rub them smooth with a flannel mop in
clean water. They are then ready to receive the
pulp from the mill. The mercury now is fed
into the battery every half hour. The quantity
must be governed by the amount of gold in the
ore. Two and one-half ounces of mercury is suf-
ficient to amalgamate and hold in proper condi-
tion on the plates one ounce of gold. The mill-
man must keep the plates in good condition, that

58 PRACTICAL MINING

is, the mercury should be kept soft on the plates
but not to run, so that it may be rubbed up with
the ringer, feeling like soft putty, and as the
amalgam accumulates, it should be kept in like
condition, but must be spread on the plates, and
not be allowed to remain in bunches as it will.
This may be done with a brush, going over the
plates from side to side, the brush in this manner
forming very fine ridges. When the ore carries
black oxide of manganese or black sulphurets
the plates become foul so often that it is a very
hard matter to keep them clean, and the follow- -
ing maybe found very useful not only in keeping
the plates clean but in saving the fine gold.

Take some light tent cloth or heavy cotton
drilling; cut a piece six feet long and the width
of the plates; tack or sew a narrow, thin lath
across each end and in the middle to keep the
cloth stretched like a window shade. Place this
right over the plates thirty inches from the bat-
tery and just below the first copper, raise the
upper end so that all the pulp and water flows
under. Allow the whole piece to float on the
pulp. You may add a little more water below
the battery. This arrangement serves to force
the fine gold on to the plate and at the same time
serves to force the foul matter off.

PRACTICAL ASSAYING 59

Sometimes the water prevents amalgamation
and causes the loss of the fine gold, even when
the plates seem to be in perfect condition. This
is often the case when the water is used from
the mine in the batteries. When this is the case
the water should be kept in a tank, adding one
bushel of lime for every 1 ,000 gallons of water.

Sodium Amalgam. — This is prepared by dis-
solving dry chips cut from clean metallic sodium
in dry mercury. Heat it very gently in a flask
or porcelain dish; add the chips of sodium piece
by piece until the mass has become thick. This
must always be kept perfectly dry and air tight.

CHLORINATION.

On page 60 see apparatus for making a chlo-
rine test, which can be purchased for $1.50.

Place in the bottom of the funnel "C" some
quartz pulverized pretty fine, a layer first of the
coarser, and cover with the fine quartz. This is
for the filter; then put into the funnel one or two
ounces of the concentrates or sulphurets which
must be roasted to destroy the sulphur, to be
treated, on top of the quartz; then place the
cover (cut out of a pine board) over the whole
and lute it down with dough. Now mix one
ounce of black oxide of manganese and one
ounce of fine salt, and put it into the generator,

PRACTICAL MINING

<
<

H
u

PRACTICAL ASSAYING 61

"A;" then' connect the generator, as shown. To
wash bottle or any clear bottle rilled with water
as shown, above the end of the glass tube, con-
nect this bottle wi'h rubber tube to the bottom
of the funnel as shown. Now * pour into the
small funnel top of glass tube in the generator,
"A;" water to cover the manganese and salt, and
then add 2 ounces of sulphuric acid, a little at a
time, and in a minute or two you will see the
chlorine gas begin to bubble up through the
water in the bottle, and this gas will pass
through the rubber tube in the ore in the funnel
and will dissolve the gold. If there is a leak
you will detect it at once by the smell, and you
can readily discover it by dipping a stick or a
sliver into ammonia and holding it all around
.the different connections, as you would do with
a lighted match, to discover a gas. The moment
the stick wet with ammonia is touched with the
gas, a whitish fume will rise from the stick.
The leak when found can be checked at once
with dough. When the bubbles cease in the
bottle, add a little more acid; let it work for six
or eight hours, then take the cover from the ore,
and remove the rubber tube from the bottom of
the funnel and place a bowl under the funnel
and begin to pour hot water on the ore, which
will leach down . through the ore and carry the

62 PRACTICAL MINING

chloride of gold with it in solution, after it has
been thoroughly leached out. You precipitate
the gold from the solution with sulphate of iron
and a few drops of muriatic acid, which you can
make by dissolving any hoop iron or thin sheets
of iron in sulphuric acid. The whole is filtered
and the brown precipitate is then dried and
mixed with litharge and borax, and melted.
The lead button is then cupelled as in an assay.
The better way is to thoroughly rinse the ore
with hot water, to leach out all the gold, and
assay for the pulp to determine the per cent, of
gold extracted.

TO MEASURE INACCESIBLE DISTANCES.
A very simple and convenient method of meas-
uring inaccessible distances, as across a canyon
or river is shown on page 63. Suppose it is de-
sired to know the distance from a given point as
" A " across a stream to " E " (see cut . ) Step off or
measure with a line, 100 feet, yards, or rods, at
right angles from the starting point "A" to "B,"
and set a stake on the same line at 80, one-fifth
of the 100 at "D." Now measure or step off at
right angles from ' 'B" to a point 4 'C, " where a line
to "E" will cut the stake at "D" as shown by the
dotted line from "C" to "E." Now the distance
from "B" to "C" multiplied by four gives the
correct distance from ''A" to "E."

PRACTICAL ASSAYING

^$^, :;,.;•;; ,;;:,;/;/.:. v

w\«v, f;

1 '■■ \ & wzz

PRACTICAL MINING

PRACTICAL ASSAYING 65

LEVELING INSTRUMENT.

There are very many times and places where
it is necessary to know the depth of shaft to tap
a drift or the length of a tunnel to cut a shaft,
and it is very seldom convenient to have a sur-
veyor or even a compass. On page 64 I have
shown a cut of an instrument I have made and
u.3ed, that is very simple, satisfactory, and easily
made. Take two pieces of hard, sound, clear
board, \ inch thick, 1 inch wide and two feet
long, dressed, and rule them the same as an or-
dinary two foot rule. Fasten them together at
one end with a common wood screw ; now cut a
quadrant, and j inch or more out of a piece of
thin brass or tin and mark the degrees on it from
0 to 90, as shown at "C;" the \ inch is to fasten
to the base "A;" let "0" begin at the top edge
of "A." Let this in flush with the face of the
piece "A" and fasten with small screws; now
take a piece of glass tubing, cork one end and
fill it with alcohol; cork and seal both ends;
countersink a place in the middle of base "A"
and fasten this in it as shown at "D." This
makes a good spirit level of the base. Stick a
piece of a pin in each end of the leg " B , " for
sights; now the instrument is ready for use. For
grading a ditch or flume, or tunnel, push the leg
"B" below the base, the number of inches re-

PRACTICAL MINING

quired for the grade, if end of the leg "B" is
pushed below the end of the level — 2 inches.
This would make the grade one inch to the foot,
etc., holding the base level; the leg "B" forms
the pitch, or incline, or base required.

For measuring distances, running tunnels,
etc., when it is desired to know the length of a
tunnel to cut a lode or shaft: Let ''A," fig. 1,

Figure 1.

be the top of the lode or shaft, and "C" be the
point where the tunnel is to start. Now place
the instrument level at "C;" let the leg "B"
point to "A," and note the angle, and then
measure the distance carefully up to the shaft at
"A," and take the pitch, or angle, of the incline
or pitch of the shaft. Now from the table of
sines, get the sine of the angle at "c" and the
sine of the angle at "a;" then the

Length of tunnel "B - e"==MAC"Xsine "a".
Depth of shaft "A - B"="AC"Xsine "c".

PRACTICAL ASSAYING
C

FlGURK 2.

Suppose it is desired to get the distance to a
certain point, with the instrument, accurately, set
a stake at the starting point, "A;" then measure
off any distance at right angles from the line
"AC" to point "B," set the base or level at "B"
and sight back to "A;" then point the leg of the
instrument to "C" and note the angle, which in
this example, figure 2, is 60°, then the angle at
"C" must be 30° and the distance from "A" to
' *B" is 80 (feet, yards or rods). The distance from

A" to "C" =

AB" Xsine"b'

sine c
Example: Angle at "B" is 60°, sine 8660.
(See table of sines.) Angle at "C" is 30°, sine
5000. Now the line "AB" is 80 X 8660 = 6928
-f- 5000 = 138.56.

68 PRACTICAL MINING

SUNDRY ITEMS.

DIFFERENT GRADES OF GOLD.

Twenty-four-carat gold is all gold; 22-carat
gold has 22 parts of gold, one of silver and one
of copper; 18-carat gold has 18 parts of gold and
three each of silver and copper; 12-carat gold is
half gold and has 3^ parts of silver and 8^ of
copper. Its specific gravity is about 15; pure
gold is 19.

LOCATION NOTICE.

There are many forms; the shortest and most
concise is as good as any, besides being the eas-
iest. Take a soft pine board and a hard lead
pencil, and the writing will sometimes outlast
your claim. I have written notices that have
remained legible for six years.

"Notice is hereby given that I, Samuel Bur-
bank, claim by right of discovery and to locate
under the mining laws of the state of California,
1,500 feet in length and 600 feet in width along
this vein or lode to be known as the "Gold Bug"
beginning at center of this shaft (cut or mound)

PRACTICAL ASSAYING 69

and running 700 feet in a northerly direction and
800 feet in a southerly direction, together with
300 feet on either side of this vein or lode.
Located January 1, 1897.

Samuel Burbank, Locator."

Now have a copy of this recorded.

MINER'S INCH.

An outlet of two inches width, four inches of
water above the outlet, one inch wide, is two
miner's inches, and a flume ten inches with six
inches of water, would give twenty miner's
inches.

SOLUTION NO. 3 FOR WORKING BLACK
SAND.

Dissolve one pound of cyanide potassium and
two pounds of caustic soda in 40 gallons of
water. Use one gallon of this solution mixed
with six gallons of water. This will free the
gold so that it will amalgate when it comes in
contact with the mercury.

209 fee"t square is one acre.

A gallon of fresh water weighs 8-J pounds, and
contains 231 cubic inches.

70 PRACTICAL MINING

A cubic foot of water weighs 62^ pounds, and
contains 1,728 cubic inches or 1\ gallons. A
cubic inch of water weighs .0361 pounds.

The friction of water in pipes increases as the
square of its velocity.

The capacity of pipes increases as the square
of the diameters, thus doubling the diameter
increases the capacity four times.

To find the area of a piston, square the diame-
eter and multiply by .7854.

In calculating horse power of tubular boilers,
15 square feet of heating surface is equivalent to
one nominal horse power.

Each nominal horse power of boilers will re-
quire about one cubic foot of water per hour.

The mean pressure of the atmosphere is usu-
ally estimated at 14.7 pounds per square inch, so
that, with a perfect vacuum, it will sustain a
column of mercury 29.9 inches, or a column of
water 33.9 feet high.

To find the capacity of a cylinder in gallons:
Multiplying the area in inches by the stroke in
inches will give the total number of cubic inches:
divide this amount by 231 (which is the cubical
contents of a gallon in inches), and the product
is the capacity in gallons.

PRACTICAL ASSAYING 71

To find the pressure in pounds per square
inch of a column of water, multiply the height
of the column in feet by .434. Approximately
each foot elevation is called equal to one-half
pound pressure per square inch.

To find the diameter of a pump cylinder to
move a given quantity of water per minute at a
piston travel of 100 feet per minute, divide the
number of gallons by 4, then extract the square
root, and the product will be the diameter of the
pump cylinder in inches.

To find the horse power required to elevate
water to a given height, multiply the amount of
water, in gallons, to be raised per minute by
8.35, the weight of a gallon of water, and this
product by the height (in feet) of the discharge
from the point of suction; divide the result by
33,000, and you have the theoretical horse power
required to raise the amount of water a certain
distance. Owing to the friction of water in
pipes, the friction of machinery and the pump
itself, a liberal allowance must be made for fric-
tion .

The area of the steam piston, multiplied by
the steam pressure, give the total amount of
pressure exerted. The area of the water piston,
multiplied by the pressure of water per square

72 PRACTICAL MINING

inch, gives the resistance. A margin of from 30
to 50 per cent, must be added to move the piston
at the required speed.

To find the velocity in feet per minute neces-
sary to discharge a given body of water in a
given time, multiply the number of cubic feet of
water by 144, and divide the product by the area
of the pipe in square inches.

Amount of water to mill one ton of ore is from
1,200 to 2,400 gallons, the average being about
1,800 gallons to the ton of ore.

Small particles of anything may be picked up
with the moistened point of a pin or needle.

PRACTICAL ASSAYING

ASSAY TABLE

Showing the amount of Gold and Silver, in ounces and frac-
tions, contained in one ton of ore. of two thousand pounds, from the
weight of fine metal obtained in an assay of (half an ounce) two
hundred and forty grains of ore.

If 240
!of Ore
of Fine
- Thoi
of the i
10 graii

One t
Ore wil
of Fine
—Ounc

. ^ v.

Intrins

ue per
Gold .

— Zl ^ >=i '7Q

xUhll

5 t*"*o

: lr

:. 53'

E.a«,

.001

1.21

$ 1.56

$ 25.01

2.43

3.14

60.23

3.64

4.71

75.24

4.86

6.28

100.40

6.08

7.86

125.68

7.29

9.42

150.70

8.51

10.99

175.92

9.72

12.57

200.93

10.94

14.14

226.15

.010

12.15

15.69

251.1)

13.37

17.29

276.88

14.58

18.85

301.29

15.80

20.43

326.61

17.01

21.99

351.63

18.23

23.57

376.85

19.44

25.13

401.80

20.66

26.71

427.08

21.87

28.27

432.09

23.09

29.85

477.31

.020

24.30

31.42

502.32

25.51

32.99

527.54

26.74

34.57

552.76

27.95

36.14

577.78

29.17

37.71

601.00

30.38

39.28

628.01

31.60

40.86

653.23

32.81

42.42

678.24

34.03

44.00

703.43

35.24

43.56

728.47

.030

36.46

47.14

753.69 I

37.67

48.70

778.71

38.89

50.28

803.93

40.10

51.85

838.94

41.32

53.42

854. i<;

42.53

54.99

879.17

43.75

56.56

901.39

44.96

58.13

929.40

46.18

59.71

954.62

47.39

61.27

979.04

PRACTICAL MINING

ASSAY TABLE — Continued.

Showing the amount of Gold and Silver, in ounces and frac-
tions, contained in one ton of ore, of two thousand pounds, from the
weight of fine metal obtained in an assay of (half an ounce) two
hundred and forty grains of ore.

If 240 j
of Ore
of Fine
— Thou
of the u
10 graii

One t
Ore wil
of Fine
— Ouno

0>S M

OSS
0^5.

2*o 2.

. 2 3

: ^ v>

grains
give
Metal
sands
init of
is.

FH£8

ELSE,

i 52

if*

.040

48.61

$ 62.85

$ 1004.86

49.83

64.43

1030.07

51.04

65.99

1055.09

52.26

67.57

1080.31

53.47

69.13

1105.32

54.69

70.71

1130.54

55.90

72.27

1155 . 55

57.12

73.85

1180.77

58.33

75.42

1205.79

59.55

76.99

1231.00

.050

60.76

78.56

1256.02

61.98

80.13

1281.24

63.19

81.70

1306.25

64.41

83.28

1331.47

65.62

84.84

1356.48

66.84

86.42

1881.70

68.05

87.98

1406.72

69.27

89.56

1431.93

70.48

91.12

1456.95

71.70

92.70

1482.17

.060

72.92

94.28

1507.39

74.13

95.84

1532.40

75.35

97.42

1557.62

76.56

98.99

1582.63

77.78

109.56

1607.85

78.99

102.13

1632.86

80.21

103.70

1658.08

81.42

105.27

1683.10

82.64

106.85

1708.32

83.85

108.41

1733.33

.070

85.07

109.99

1758.55

86.28

111.55

1783.56

87.50

113.13

1808.78

88.71

114.69

1883.79

89.93

116.27

1859.01

91.14

117.84

1884.08

92.36

119.41

1909.25

93.58

120.99

1984.47

94.79

122.56

1959.48

96.01

124.13

1984.70

PRACTICAL ASSAYING

ASSAY TABLE — Continued.

If 240 grains
of Ore give
of Fine Metal
— Thonsandr
of the unit of
10 graitis.

One ton of
Ore will yield
of Fine Metal
—Ounces.

*n a

: \\

0 **

£•0 2.

.080

97.22

$ 125.70

$ 2009.71

98.44

127.27

2034.93

99.65

128.84

2059.94

100.87

130.42

2085.16

102.08

131.98

2110.18

103.30

133.56

2135.40

104.51

135.12

2160.41

105.73

136.70

2185.63

106.94

138.26

2210.64

108.16

139.84

2235.86

.090

109.37

141.41

2260.87

110.59

142.98

2286.09

111.80

144.55

2311.11

113.02

146.13

2336.33

114.23

147.69

2361.34

115.45

149.27

2386.56

116.67

150.84

2411.78

117.88

152.41

2436.79

119.10

153.99

2462.01

120.31

155.55

2487.02

.100

121.53

157.13

2512.24

.200

243.05

314.26

5024.48

.300

364.58

471.39

7536.72

.400

486.11

628.52

10048.96

.500

607.64

785.65

12561.21

.600

729.16

942.78

15073.45

.700

850.69

1099.91

17585.70

.800

972.22

1257.04

20097.93

.900

1093.75

1414.17

22610.17

1.000

1215.27

1571.30

25121.41

PRACTICAL MINING

ASSAY TABLE

Showing the amount of Gold and Silver, in ounces and fractions,
contained in one ton of ore, of two thousand pounds, from the
weight of fine metal obtained in an assay of 20 Grammes of ore.

MO , 0 0 m

| o oo

crse y

OS t?

f 20 grams
f Ore give
f Fine Metal
- Thousands
f the unit of
G^ram.

: 3S'
: E.S2,

o n 2.

• 3 3

.001

1.458

$ 1.88 5

$ 30.14 6

2.916

3.77.1

60 29.2

4.374

5.65.7

90.43.8

5 833

7.54.2

120 58.5

7.291

9.42.8

150.73.1

8 749

11.31 3

180.87.7

10.208

13.19 8

211.02.4

11.666

15.08.4

241.17 0

13.124

16.95.9

271 31.6

.010

14.583

18.85.4

301.46.3

16.041

20.73.9

331 60.9

17.499

22.62.5

361.75.5

18.958

24.51.0

391.90.1

20.416

26.39.5

422.04.8

21.874

28.28.1

452.19.4

23.333

30.16.6

482.34.0

24.791

32.05.2

512.48.7

26.249

33.93 7

542.63.3

27.708

35.82.4

572.77.9

.020

29.166

37.70.8

602.92.6

30.624

39.59.4

633.07 2

32.083

41.47.9

663.21.8

33 541

43.36.4

693.36.5

34.999

45.25 0

723.51.1

36.458

47.13.5

753.65.7

37.916

49.02.1

783.80.3

39.374

50.90.6

813.95.0

40.833

52 79.2

844.09.6

42.291

54.67.7

874.24.2

.030

43.749

56 56.2

904.38.9

45.208

58.44.8

934.53.5

40.636

60.33.3

964 68.1

48.124

62.21.9

994.82 8

49.583

64.10.4

1024.97.4

51 041

65.99.0

*)55.12.0

52.499

67.87.5

1085 26.7

53.958

69.76.0

1115.41 3

55.416

71.64.6

1145.55.9

56.874

73.53.1

1175.70.5

.040

58.333

75.41.9

1205.85.0

59.791

77.30.4

1235.99.8

61.249

79.18.9

1266.11.4

62.708

81.07.5

1296.29.1

PRACTICAL ASSAYING

ASSAY TABLE — Continued.

Showing the amount of Gold and Silver, in ounces and fractions,
contained in one ton of ore, of two thousand pounds, from the
weight of fine metal obtained in an assay of 20 Grammes of ore.

MO i o o •-*

| o OO

C/5C JH

qc tr1

f 20 gram
f Ore giv
fFineMeta
- Thousand
f the unit o
Gram.

Crt B

o n 5.

0^2 %
g a *

: £5"
: S.S2,

if}

En 5.

■ 2 3

•*, w h- rt tc

1 i

.044

64.166

$ 82.96.0

$ 1326.43.7

65.624

84.84.6

1356.58.3

67.083

86.73.1

1386.73.0

68.541

88.61.7

1416.87.6

69.999

90.50.2

1447.02.2

71.458

92.38.7

1477.16.8

.050

72.916

94.27.3

1507. SI. 5

74.374

96.15.9

1537.4'J.l

75.833

98.04.4

1557.60.7

77.291

99.93.0

1597 75.4

78.749

101.81.5

1627.90.0

80.208

103.70.1

1658.04.6

81.666

105.58.6

1688.19.3

83.124

107.47.1

1718.33.9

84.583

109.35.7

1748.48.5

86.041

111.24.2

1778.63.2

.060

87.499

113.12.8

1803.77.8

88.958

115.01.3

1838.92.4

90.416

116.89.9

1869.07.0

91.874

118.78.4

1899.21.7

93 333

120.67.0

1929.36.3

94.791

122.55.5
124.44.0

1959.50.9

96.249

1989.65.6

97.708

126.32.6

2019.80.2

99.166

128.21.1

2049.94.8

100.644

130.09.7

2080.09.5

.070

102.083

131.98.3

2110.24.1

103.541

133.86.8

2140.38.7

104.999

135.75.4

2170.53.4

106.458

137.63.4

2200.68.0

107.916

139.52.4

2230.82.6

109.374

141.41.0

2260.97.2

110.833

143.29.5

2261.11.9

112.291

145.18.1

2321.26.5

113.749

147.03.6

2351.41.1

115.208

148.95.2

2381.55.8

.080

116.666

150.83.7

2411.70.4

118.124

152.72.2

2411.85 0

119.583

154 60.7

2471 99 7

121.041

156 49.4

2502.14.3

122.499

158.37 9

2532.28 9

123 957

160.26 5

2562.43.6

125.416

162.15.0

2592.58.2

PRACTICAL MINING

ASSAY TABLE — Continued.

Showing the amount of Gold and Silver, in ounces and fractions
contained in one ton of ore. of two thousand pounds, from the
weight of fine metal obtained in an assay of 20 Grammes of ore.

Mai a© a

1 2,oo

oi: U

QCf

20 grams
Ore give
Fine Metal
Thousands
the unit of
gram.

If J

2 n

:. El

2." 2-

. 2 3
. n en

.087

126.874

$ 164.03.5

$ 2622.72.8

128.332

165 92.5

2652.87 4

129 791

167.80.6

2683.02.1

.090

131 249

169.69.2

2713.16.7

132.708

171.57.7

2743.31.3

134.106

173.46.3

2773.46.0

135.624

175.34.8

2803.60.6

137.083

177.23.3

2833.75.2

133.541

179.11.9

2863 89.9

139.999

181.00.4

2894.04.5

141.458

182 89.0

2924 19.1

142.916

184.77.5

2954.33.7

144.374

186.66.1

2984.48.4

.100

145.833

188 54.7

3014.63.0

.200

291.666

377.09

6029.26

.300

437.499

565.64

9013 91

.400

583.333

754.19

12058.55

.500

729.166

942.73

15073 18

.600

874.999

1131.29

18087.82

.700

1020.833

1319.83

21102.46

.800

1166.666

1508.38

24117 09

.900

1312.499

1696.93

27131 73

1.000J
Orl GraniJ

1458 333

1885 47

30146.37

2 ..

2916.666

3770.95

60292.74

3 ..

4374.999

5656.42

90439.10

4 ..

5833.333

7541.90

120585.47

5 ..

7291.666

9427.37

150731.84

6 ..

8749.999

11312.85

180878.21

7 ..

10208.333

13198.32

211024.58

8 ..

11666.666

15083.80

241170.94

9 ..

13124.999

16964.27

271317.31

10 ..

14583.333

18854.75

301403 68

11 ..

16041.664

20740.22

331610.05

12 ..

17499 999

22625.70

361756.42

13 ..

18958.333

24511 17

391902.78

14 ..

20416.666

26396.65

422049.15

15 ..

21874.999

28282.12

452195.52

16 ..

23333.333

30107.60

482341.89

24791.666

32053.07

512488.25

18 ..

26249.999

33938.55

542634.62

19 ..

27708.333

35824.02

572780.99

20 ..

29166.666

37709.50

602927.36

PRACTICAL ASSAYING 79

The foregoing table is computed from an assay
of 20 grammes, which is a convenient amount
for a crucible assay. When a scorification assay
is made, two scorifiers are used with 10 grammes
in each, and the two buttons (which should
weigh exactly alike, if the assay is correct) are
weighed together and treated as one assay. It is
then only necessary to compare the tables with
the number of milligrammes obtained, in the
first column; in the next will be found the num-
ber of ounces to the ton, and the value of gold
and silver in the other columns. A single exam-
ple will fully illustrate it.

20 grammes of ore yield a metallic button of
gold and silver weighing 830 milligrammes.

Boiled in nitric acid. — Gold weighing 32 milli-
grammes remains.

380-32 gold=348 silver.

In the first column find 32 milligrammes and
you have 46.666 ozs. Troy and its value in gold
column, $964.68. In the first column find 348
milligrammes. To do this you must add 48 and
300, and you have 69. 999-f 437.499=507.49 ozs.
Troy, and its value in silver column 90.50 -j-
565.54=$656.14. The result will be,

Gold 46.666 ozs. Troy =$964.68.

Silver 507.49 " " = 656.14.

Value per ton of 2,000 lbs $17620.82.

PRACTICAL MINING

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PRACTICAL MINING

TABLE OF NATURAL SINES.

[ De-
gree.

10'

20'
.0058

30'

40'

50'

.0000

.0029

.0087

.0116

.0145

.0175

.0204

.0233

.0262

.0291

.0320

.0349

.0378

.0407

.0436-

.0465

.0494

.0523

.0552

.0581

.0610

.0640

.0669

.0698

.0727

.0756

.0785

.0814

.0843

.0872

.0901

.0929

.0958

.0987

.1016

.1045

.1074

.1103

.1132

.1161

.1190

.1219

.1248

.1270

.1305

.1334

.1363

.1392

.1421

.1449

.1478

.1507

.1536

.1564

.1593

.1622

.1650

.1679

.1708

.1736

.1765

.1794

.1822

.1851

.1880

.1908

.1937

.1965

.1994

.2022

.2051

.2079

.2108

.2136

.2164

.2193

.2221

.2250

.2278

.2306

.23:34

.2363

.2391

.2419

.2447

.2476

.2504

.2532

.2560

.2588

.2616

.2644

.2672

.2700

.2728

.2756

.2784

.2812

.2840

.2868

.2896

.2924

.2952

.2979

.3007

.3035

.3062

.3090

.3118

.3145

.3173

.3201

.3228

.3256

.3283

.3311

.3338

.3365

.3393

.3420

.3448

.3475

.3502

.3529

.3557

.3584

.3611

.3638

.3665

.3692

.3719

.3746

.3773

.3800

.3827

.3854

.3881

.3907

.3934

.3961

.3987

.4014

.4041

.4067

.4094

.4120

.4147

.4173

.4200

.4226

.4253

.4279

.4305

.4331

.4358

.4384

.4410

.4436

.4462

.4488

.4514

.4540

.4566

.4592

.4617

.4643

.4669

.4695

.4720

.4746

.4772

.4797

.4823

.4848

.4874

.4899

.4924

.4950

.4975

.5000

.5025

.5050

.5075

.5100

.5125

.51^

.5175

.5200

5225

.5250

.5275

.oi99

.5324

.5348

.5373

.5398

.5422

.5446

.5471

.5495

.5519

.5544

.5568

.5592

.5616

.5640

.5664

.5688

.5712

.5736

.5760

.5783

.5807

.5831

.5854

. .5878

.5901

.5925

.5948

.5972

.5995

.6018

.6041

.6065

.6088

.611il

.6134

.6157

.6180

.6202

.6225

.6248

.6271

.6293

.6316

.6338

.6361

.6383

.6406

.6428

.6450

.6472

.6494

.6517

.6539

.6561

.6583

.6604

.6626

.6648

.6670

.6691

.6713

.6734

.6756

.6777

.6799

i 43

.6820

.6841

.6862

.6884

.6905

.6926

.6947

.6967

.6988

.7009

.7030

.7050

PRACTICAL ASSAYING

TABLE OF NATURAL SINES.

De-
gree.

10'

20'

30'

40'

50'

.7071

.7092

.7112

.7133

.7153

.7173

.7193

.7214

.7234

.7254

.7274

.7294

.7314

.7333

.7353

.7373

.7392

.7412

.7431

.7451

.7470

.7490

.7509

.7528

.7547

.7566

.7585

.7604

.7623

.7642

.7660

.7679

.7698

.7716

.7735

.7753

.7771

.7790

.7808

.7826

.7844

.7332

.7880

.7898

.7916

.7934

.7951

.7969

.7986

.8004

.8021

.8039

.8056

.8073

.8090

.8107

.8124

.8141

.8158

.8175

.8192

.8208

.8225

.8241

.8258

.8274

.8290

.8307

.8323

.8339

.8355

.8371

.8387

.8403

.8418

.8434

.8450

.8465

.8480

.8496

.8511

.8526

.8542

.8557

.8572

.8587

.8601

.8316

.8631

.8646

.8560

.8375

.8339

.8704

.8718

.8732

.8746

.8760

.8774

.8788

.8302

.8316

.8329

.8343

.8857

.8370

.8884

.8897

.8310

.8923

.8936

.8949

.8962

.8975

.8988

.9001

.9013

.9026

.9038

.9051

.9033

.9075

.9088

.9100

.9112

.9124

.9135

.9147

.9159

.9171

.9182

.9194

.9205

.9216

.9228

.9239

.9250

.9202

.9272

.9283

.9293

.9304

.9315

.9325

.9336

.9346

.9356

.9337

.9377

.9387

.9397

.9407

.9417

.9426

.9436

.9446

.9455

.9435

.9474

.9433

.9492

.9502

.9511

.9520

.9528

.9537

.9546

.9555

.9563

.9572

.9580

.9588

.9596

.9605

.9613

.9321

.9328

.9336

.9344

.9652

.9359

.9337

.9374

.9331

.9689

.9696

.9703

.9710

.9717

.9724

.9730

.9737

.9744

.9750

.9757

.9763

.9769

.9775

.9781

.9787

.9793

.9799

.9305

.yail

.9316

.9322

.9827

9333

9338

.9843

.9348

.9353

.9858

.9833

.9368

.9372

.9377

.9331

.9386

.9390

.9394

.9899

9903

.9907

.9911

9914

9918

.9922

.9925

.9929

.99:32

.9936

.9939

.9942

.9945

.9918

.9951

.9954

.9957

.9959

.9962

.99(54

.9967

.9969

.9971

.9974

.9976

.9978

.9980

.9981

.9933

.9985

.9986

.9933

.9989

.9990

.9992

.9993

.9994

.9995

9996

.9997

.9993

.9998

.9999

1.0000

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90 PRACTICAL MINING

MINING LAWS.

The Legislature of 1897 enacted more mining
laws than any previous legislative body in the
State.

Through the exertions of the Legislative Com-
mittee of the Miner's Association, of which
Tirey L. Ford is chairman, and also the good
work done by Joseph H. NefF, President;
Samuel Thornton, Vice President, and Julian
Sonntag, Secretary of the Association, backed
by Assemblyman Howard of Sierra, who held
the proud position of Chairman of the Assembly
Committee on Mines and Mining, and who was
the principal factor in obtaining favorable mining
legislation, Senators Presk of Nevada, Boyce of
Santa Barbara, Chapman of El Dorado, Gleaves
of Shasta, Shine of Tuolumne, Smith of Kern
and Voorhies of Amador counties, and Assem-
blymen Caminetti of Amador, Power of Placer,
Robinson of Nevada, Burnham of El Dorado and
Fontana of Calaveras counties, more legislative
enactments of a practical character were pushed
through to the Governor, who signed them will-
ingly, than at any other period in the history of
the State.

Among the many measures which were intro-
duced and finally passed were the following:

PRACTICAL ASSAYING 91

First; All legal impediments were removed from
the appropriation of $250,000, which was allowed
by the State for the impounding of debris, thus
making available for that object $500,000, as the
General Government had already appropriated a
like amount pending the action of the State
Legislature.

Second; An act providing for the manner of
locating and recording mining claims.

And it is a remarkable fact that though Cali-
fornia was the first State to make large and won-
derful discoveries of gold, it was the last to enact
laws regulating , locating and recording of miner-
al claims. Every other mining State and Terri-
tory passed laws to cover these important points
as soon as the conditions presented themselves;
but the Golden State — the State replete with the
history of Argonauts and mushroom millionaires
— the mecca of prospectors for the past quarter
of a century; neglected to protect her miners by
wholesome laws until this late day. The follow-
is a copy of Assembly Bill, No. 551.

Section 1. The location of mining claims
upon the public domain of the United States
shall be made and perfected as provided in this
Act.

Sec. 2. The discoverer of any vein or lode
shall immediately, upon making discovery, erect

92 PRACTICAL MINING

at the point of discovery a substantial monument,
or mound of rocks, and post thereon a prelimin-
ary notice which shall contain:

First — The name of the lode or claim;

Second — The name of the locator or locators;

Third — The date of the discovery;

Fourth — The number of linear feet claimed in
length along the course of the vein each way
from the point of discovery;

Fifth — The width claimed on each side of the
center of the vein;

Sixth — The general course of the vein or lode,
as near as may be;

Seventh — That such notice is a first or pre-
liminary notice.

Such notice shall be recorded in the office of
the County Recorder of the county in which the.
same is posted within twenty days after the
posting thereof. Upon the erection of said
monument and posting such notice, the discover-
er shall be allowed the period of time specified in
section three of this Act to enable him to perfect
his location as hereinafter provided.

Sec. 3. Within sixty days from the date of
the discovery of the vein or lode, the discoverer
must perform fifty dollars' worth of labor in de-
veloping his discovery, and distinctly mark his
location on the ground so that its boundaries can

PRACTICAL ASSAYING 93

be readily traced, and must file in the office of
the County Recorder of the county in which the
claim is situated, a certificate of location, which
said certificate shall state:

1. The name of the lode or claim;

2. The name of the locator or locators;

3. The date of discovery and posting of the
notice, provided for in section two of this Act,
which shall be considered as the date of the lo-
cation.

4. A description of the claim, defining the ex-
terior boundaries as they are marked upon the
ground, and such additional description by re-
ference to some natural objects, or permanent
monument, as will identify the claim.

5. A statement that such certificate is the final
or completed notice of location, and that he has
performed the aforesaid fifty dollars' worth of
labor in development work thereon within the
aforesaid sixty day period, stating generally the
nature thereof. Said certificate shall be dated
and signed by or on behalf of the locator or lo-
cators, and verified by them or by some one in
their behalf, and when filed for record shall be
deemed and considered as prima facie evidence
of the facts therein recited. A copy of such
certificate of location, certified by the County
Recorder, shall be admitted in evidence in all

94 PRACTICAL MINING

actions or proceedings with the same effect as the
original. The performance of snch labor shall be
deemed a necessary act in completing such loca-
tion and a part thereof, and no part thereof shall
inure to the benefit of any subsequent location.

Sec. 4. The discoverer of placers or other
forms of deposit, subject to location and appro-
priation, under mining laws applicable to placers,
shall locate his claim in the following manner:

First — He must immediately post in a con-
spicuous place at the point of discovery thereon
a notice or certificate of location thereof contain-
ing:

(a) The name of the claim.

(b) The name of the locator or locators.

(c) The date of the discovery and posting of
the notice, hereinbefore provided for, which
shall be considered as the date of the location.

(d) A description of the claim by reference to
legal subdivisions of sections, if the location is
made in conformity with the public surveys;
otherwise, a description with reference to some
natural object or permanent monument as will
identify the claim, and w here such claim is lo-
cated by legal subdivisions of the public surveys,
such location shall, notwithstanding that fact,
be marked by the locator upon the ground, the
same as other locations.

PRACTICAL ASSAYING 95

Second — Within thirty days from the date- of
such discovery he must record such notice or
certificate of location in the office of the County
Recorder of the county in which such disco very
is made, and so distinctly mark his location on
the ground that its boundaries can be readily
traced.

Third — Within sixty days from the date of the
discovery the discoverer shall perform labor upon
such location or claim in developing thereto an
amount which shall be equivalent in the aggre-
gate to at least ten dollars' ($10) worth of such
labor for each twenty acres, or fractional part
thereof, contained in such location or claim.

A failure to perform such labor within said
time, shall cause all rights under such location
to be forfeited and the land discovered thereby
shall at once be open to location by qualified lo-
cators other than the proceeding locators, but
shall not in any event be open to location by
such proceeding locators, and any labor per-
formed by them thereon shall not inure to the
benefit of any subsequent locator thereof.

Fifth — Such locator shall, upon the perform-
ance of such labor, file with the Recorder of
the county an affidavit, showing such perform-
ance, and generally the nature and kind of
work so done.

96 PRACTICAL MINING

Sec. 5. The affidavit provided for in the last
section, and the aforesaid placer notice or certifi-
cate of location when filed for record, shall be
deemed and considered as prima facie evidence
of the facts therein recited. A copy of such cer-
tificate, notice or affidavit, certified by the
County Recorder, shall be admitted in evidence
in all actions or proceedings with the same effect
as the original.

Sec. 6. All locations of quartz or placer for-
mations of deposits, hereafter made, which do
not conform to the requirements of this Act, in
so far as the same are respectively applicable
thereto, shall be void.

Sec. 7. No record of a mining claim or mill
site, made after the passage of this Act, in the
records of any mining district, shall be valid.
All notices of location of mining claims, mill
sites, and other notices, heretofore recorded in
such district records, if such notices conform to
the local rules and regulations in force in such
district, are hereby declared valid. Within
thirty days after the passage of this Act the
district recorder or custodian of the records of
the several mining districts in this State, shall
transmit to the County Recorders of the respec-
tive counties, wherein the respective districts
are situated, all the records of said respective

PRACTICAL ASSAYING 97

districts, and thenceforward such County Re-
corder shall be deemed and considered the legal
custodian of such records. Thereafter copies of
such records, certified by the County Recorder,
may be received in evidence with the same effect
as the originals.

Sec. 8. This Act shall take effect and be in
foTce sixty days after its passage.

Third; The act of 1880, which provided a
penalty of $1,000 for failure of any mining com-
pany to post monthly accounts in its office, was
amended so as to allow any stockholder to sue
for any actual damage sustained by a neglect
to post such notice. The old law worked a
hardship oh the small companies, located perhaps
miles from any town, in mountainous districts,
where it would be sometimes difficult to post
such monthly statements. With the exception
of the right to sue for actual damages instead of
the $1,000 specified in the old statute, the law is
still in force.

Fourth; By a law enacted by the recent Legis-
lature it requires the consent of the majority of the
stock, instead of two thirds of the stock as hereto-
fore, before any transfer of real estate can be made
by any mining company, and a record of such con-
sent must be filed in the County Recorder's office.

98 PRACTICAL MINING

Fifth; Where titles are given to town site lo-
cators through the Superior Judge of the district,
preferance will in all cases be given to mining
locators.

All these are good measures, and the Miners'
Association may well be proud of its work.

PRACTICAL ASSAYING 99

GLOSSARY.

Air Furnace, A fireplace at the surface for drawing
out foul air from shafts or levels by its natural draught
from combustion.

Alumina, Oxidized aluminum extracted from clays,
creolite, kaolin, bauxite, and what is generally known
as chalk rock, or aluminite.

Angles, Dips and Spurs, The side extent which can
be claimed upon a mineral vein is expressed by these
phrases.

Anhydrous, Waterless, as salts or minerals.

Antimony, A mineral, symbol Sb. Atomic weight, 129.

Aqueous, A water solution.

Arborescent, A tree-like formation of minerals.

Argol, Crude tartar. An acid salt deposited from
wine.

Arsenate, Arsenic acid united with a base.

Arseniret or Arsenide, Arsenic in chemical com-
bination with some base, as arsenide of iron, sulphur or
bismuth.

Basalt, An effusive rock composed mostly of pyrox-
ene, olivine and silica.

Bismuth, A metal. Symbol Bi. Atomic weight 213.

BlackJack, Sulphuret of zinc.

Boyer, The name of a common rock drill.

Breast or Breasting, The standing end of rock,
vein or cliff of gravel immediately before taking down
and blasting is called breasting.

100 PRACTICAL MINING

Breccia, Cemented rock composed of angular frag-
ments of one or more minerals which generally exhibit
different colors.

Calcine, To burn off and volatize.

Calcium, The metalic base of lime.

Calc Spar, A pure crystalized or borate of soda and
carbonate of lime, sometimes combined with the matrix
in vein matter.

Cap Rock, The uncertain upper rock which covers
the older bedrock .

Carbonate, Carbonic acid combined with a base as
carbonate of lead.

Carbonate of Soda, Carbonic acid and oxide of so-
dium chemically combined.

Carboniferous, As carboniferous slate or shale,
containing a little carbon, indicative of underlying coal
seams.

Counter Lode, A vein obliquely crossing the reg-
ular veins of the district.

Cellular, When a stone or mineral has many small
cavities, sponge-like.

Chloride, Chlorine chemically united with some
base, as chloride of sodium (common salt), especially
found in manganese which when dissolved in muriatic
acid gives off the fumes of chlorine gas.

Clay, Chiefly composed of alumina in a moist and
putty-like or dry, pulverized condition, often found be-
tween the vein matter and the footwall rock as gouge.

Clay Course, Mostly applied to a common clay seam
or gouge on the side of a vein.

PRACTICAL ASSAYING 101

Cleavage, The planes at which cleavable stones
break.

Cobalt, A magnetic metal, Atomic weight, 29.5.

Coherent, Firmly held together, not friable.

Compact, When a stone is all alike, not cleavable.

Conchoidal, Fracturing to an irregular shaped sur-
face like flint; brick or sand rock without any sign of
plane or cleavage.

ConglomoraTE, A pudding stone or cementation of
rocks, pebbles and sand.

Cupel, A moulded cup of bone ash for cupelling lead
from the assay, leaving the gold and silver in the form
of a bead.

Cupriferous, Containing copper, as copper ores.

Decomposed, That which has undergone artificial or
natural change, as the desulphurization and oxidation
of the sulphurets and other metals.

Dendritic or Arborescent, Shaped or crystalized
like trees.

Detritus, Finely powdered deposits worn from hard
substances.

Dike, A large zone or vein-like formation but com-
posed of bed rock or country rock instead of quartz.

Fault, A cut-off or shift of a vein or seam.

Ferruginous, Iron, iron oxide, containing iron.

Fissure, An extensive crack or chasm in a somewhat
regular plane of fracture, as a true fissure vein.

Float Stones, Sometimes called shoal rock, miner-
alized rock lying upon the surface or near vein deposits.
It sometimes directs the prospector to the vein or lode
from which it came.

102 PRACTICAL MINING

Flux, Any substance that is favorable to combustion,
oxidixation or reduction by fire.

Foliated, Lamillar or leaf-like in form, which can
be cleaved.

Fox Wedge, Wedged at two points. We find gash
veins fox wedged.

Fracture, Applied to qualify the broken surfaces of
minerals, as even or uneven fracture.

Frangible, Not tough, easily broken, brittle.

Gangue, Waste, all kinds of enclosing waste rock,
the matrix of quartz, etc., but gangues may not all be
matrixes.

Glance, Sometimes applied to glancing or shining
mineral, as copper glance, lead glance, silver glance.

Globular Concretions, Minerals occurring in
small, rounded forms.

Gossan, Very rusty and finely powdered quartz. It is
thought to be one of the best indications for minerals in
deep sections of the vein.

GOUGE, Soft clay seam between the vein matter and
the walls.

Gramme, Equal to 15,433 grains Troy.

Granular, Minerals exhibiting small grains across
the plane of the fracture.

Graphite, A mineral carbon.

GREENSTONE, A green colored, granular stone, a kind
of trap, composed of hornblende and feldspar.

Horn Silver, The common name for chloride silver
because it has a horn-like surface.

HORSE, A long, convex-sided portion of a foreign rock
completely inclosed in the quartz or vein matter.

PRACTICAL ASSAYING 103

Hydraulic Cement, A mixture of lime, magnesia,
alum and silica so that it solidifies under water.

Incrusted, When a surface is covered with some
other deposit.

Interlacing, When the threads or ribbons of one
mineral cross those of another.

Interstratified, Lying between other stratifica-
tions, as a layer of greenstone between other layers of
slate.

Lava, Igneous rock that has been melted, forced up
or thrown out from volcanoes.

Matte, The product of the first incomplete reduction
of an ore, as copper matte.

Mica, A thin, scale-like mineral of the true granite.

Oxide, A chemical combination of oxygen with a
base.

Oxygen, A gas we extract from the air in breathing;
it also forms with many acids; one-half the weight of
solid bedrock. When united with hydrogen it is water.

Paleozoic, Applied to the first rocks with fossil ani-
mals and to the older divisions of geologic time. It in-
cludes the silurian, devonian and carboniferous ages.

Platinum, A grayish-white metal infusible by ordi-
nary means, insoluble in any single acid. It dissolves in
a mixture of nitric acid one part, hydrochloric acid three
parts.

Schist or Schistose, A crystaline or metamorphic
rock having a slaty structure, as mica schist, argilla-
ceous schist, etc.

Sectile, Minerals which are sufficiently tough to cut
smoothly without crumbling.

Serpentine, Composed of the mineral serpentine,
feldspar, and pyroxene.

T C

p. G>S - ' ■

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