Getting Gold
by
J. C. F. Johnson
Part 3 out of 3
require would be a qualified, practical miner capable of opening and
securing the ground in a miner-like manner, and a good working
engineer; and in gold-mining, where the gold is free in its matrix, a
professional amalgamator, or lixiviator. For the rest, half a dozen or
more mines may collectively retain the services of a mine manager of
high attainments as general inspector and superintendent, and the same
system could be adopted with respect to an advising metallurgist and
an engineer. For gold, as indeed for other metals, a central
extracting works, where the ores could be scientifically treated in
quantity, might be erected at joint cost, or might easily be arranged
for as a separate business.
A very fruitful cause of failure is the fatuous tendency of directors
and mine managers to adopt new processes and inventions simply because
they are new. As an inventor in a small way myself, and one who is
always on the watch for improved methods, I do not wish to discourage
intelligent progress; but the greatest care should be exercised by
those having the control of the money of shareholders in mining
properties before adopting any new machinery or process.
We have seen, and unfortunately shall see, many a promising mining
company brought to grief by this popular error. The directors of
mining companies might, to use an American saying, "paste this in
their hats" as a useful and safe aphorism. "LET OTHERS DO THE
EXPERIMENTING; WE ARE WILLING TO PAY ONLY FOR PROVED IMPROVEMENTS." I
can cordially endorse every word of the following extracts from
Messrs. McDermott and Duffield's admirable little work, "Losses in
Gold Amalgamation."
"Some directors of mining companies are naturally inclined to listen
to the specious promises of inventors of novel processes and new
machinery, forgetting their own personal disadvantage in any argument
on such matters, and assuming a confidence in the logic of their own
conclusions, while they ignore the fruitful experience of thousands of
practical men who are engaged in the mining business. The repeated
failures of directors in sending out new machinery to their mines
ought by this time to be a sufficient warning against increasing risks
that are at once natural and unavoidable, and to deter them from
plunging their shareholders into experiments which, in ninety-nine
cases out of a hundred, result in nothing but excessive and needless
expenses.
"It is certain that new machines and new processes are, and will be,
given attention by mining men in proportion to their probable merits;
but the proper place for experiments is in a mill already as
successful as under known processes it can be made. In a new
enterprise, even when the expense of an experiment is undertaken by
the inventor, the loss to the mine-owner in case of failure must be
very great, both in time and general running expenses. Directors
should not believe that a willingness to risk cash in proving an
invention is necessarily any proof of value of the same; it is only a
measure of the faith of the inventor, which is hardly a safe standard
to risk shareholders' money by.
"The variety of modifications in approved processes ought at least to
suggest the desirability of exhausting the known, before drawing on
the unknown and purely speculative. It should also be borne in mind
that what might appear at first sight to be new processes, and even
new machinery, are, in fact, often nothing but old contrivances and
plausible theories long ago exploded among practical men.
"Many mining companies have been ruined, without any reference to
their mines, through men deciding on the reasonableness of new process
and machinery who have no knowledge of the business in hand. It is
assumed often, that if an inventor or manufacturer of new machinery
will agree to guarantee success, or take no pay if not successful, the
company takes no risk. In actual fact a whole year is wasted in most
cases, failure spoils the reputation of the company, running expenses
have continued, and further working capital cannot be raised, because
all concerned have lost confidence by the failure to obtain returns
promised. All this in addition to the regular, unavoidable risks of
mining itself, which may, at any moment during the year lost, call for
increased expenses and increased faith in ultimate success. To the
mining man who makes money by the business, the natural risks of
mining is all he will take; it is sufficient; and when he invests more
money in machinery he takes good care that he takes no chances of
either failure or delay.
"The following are rules which no mining company or individual mine-
owner can afford to neglect.
"(1) The risk should be confined to mining. No body of directors is
justified in taking a shareholder's money and investing it in new
processes or machinery when the subscription was simply for a mining
venture. Directors are invariably incapable of deciding whether a so-
called improvement in machinery or process is really so or not, and
the reasonable course is to follow established precedents.
"(2) The risk of selecting an incompetent manager should be reduced to
minimum by taking a man with a successful record in the particular
work to be done. The manager selected should be prohibited, as much as
the directors, from experimenting with new methods or machinery. A
really experienced man will require no check in this direction, as he
will not risk ruining his reputation.
"(3) The only time for a company to experiment is when the mine is
paying well by the usual methods, and the treasury is in a condition
to speculate a little in possible improvements without jeopardising
regular returns."
Probably this is the best place to insert another word of warning to
directors who are not mining specialists, and also to investors in
gold mining shares. Assays of auriferous lode material are almost
invariably worthless as a guide in the real value of the stone in
quantity. The one way to decide this is by battery treatment in bulk,
and then only after many tons have been put through. The reason is
obvious. First, the prospector or company promoter, if he knows it, is
not in the least likely to pick the worst piece of stone in the heap
for assay; and, secondly, even should the sample be selected with the
sole object of getting a fair result, no living man can judge the
value of a gold lode by the result of treatment of an ounce of stone.
So when you see it stated that Messrs. Oro and Gildenstein, the
celebrated assayers, have found that a sample of rock from the Golden
Mint Mine, Golconda, assays at the rate of 2,546 oz. 13 dwt. and 21
gr. to the ton, and that there are thousands of tons of similar stone
in sight, the statement should be received with due caution. The assay
is doubtless correct, but the deductions therefrom are most
misleading.
A few words of advice also to directors of mine-purchasing companies
and syndicates, of which there are now so many in existence, may
probably be found of value. It is not good policy as a general rule to
buy entirely undeveloped properties, unless such have been inspected
by your own man, who is both competent and trustworthy, and who should
have indeed an interest in the profits. Large areas, although so
popular in England, do not compensate for large bodies of payable ore;
the most remunerative mine is generally one of comparatively small
area, but containing a large lode formation of payable but often low
grade, ore.
It is worse still, of course, to buy a practically worked out mine,
though this too is sometimes done. It must be remembered that mining,
though often so profitable, is nevertheless a destructive industry,
thus differing from agriculture, which is productive, and
manufactures, which are constructive. Every ton of stone broken and
treated from even the best gold mine in the world makes that mine the
poorer by one ton of valuable material; thus, to buy a mining property
on its past reputation for productiveness is, as a rule, questionable
policy, unless you know there is sufficient good ore in sight to cover
the purchase cost and leave a profit.
One of the greatest causes of non-success of gold-mining ventures,
particularly when worked by public companies, is the lack of actual
personal supervision, and hence, among other troubles, is that ultra-
objectionable one--gold stealing from the mills, or, in alluvial
mining, from the tail races. As to the former, the following appeared
in 1893 in the London /Mining Journal/, and is, I think, worthy of the
close consideration of mine directors in all parts of the world:--
"No one that has not experienced the evil of gold thieving from
reduction mills can have any idea of the pernicious element it is, and
the difficulty, once that it has got 'well hold,' of rooting it out.
It permeates every class of society in the district connected with the
industry, and managers, amalgamators, assayers, accountants, aye, even
bank officials, are 'all on the job' to 'get a bit' while there is an
opportunity. To exterminate the hateful monster requires on the part
of the mine proprietors combined, stern and drastic measures
undertaken under the personal supervision of one or more of their
directors, and in many instances necessitating the removal of the
whole of the official staff."
The writer narrates how about twenty years ago he was led to suspect
that in an Australian mine running forty head of stamps, in which he
held a controlling interest, the owners were being defrauded of about
a fourth of the gold really contained in the ore, and the successful
steps taken to check the robbery.
"We first of all dispensed with the services of the general manager,
and then issued the following instructions to the mine and mill
managers, I remaining at the mine to see them carried out until I
substituted a practical local man as agent, who afterwards carried on
the work most efficiently:--
"(a) Both of these officials to keep separate books and accounts; in
other words, to be distinct departments.
"(b) The ore formerly was all thrown together and put through the
mill. I subdivided it into four classes, A, B, C, and D, representing
deep levels north and upper levels north, deep levels south and upper
levels south, and allotted to each class ten heads of stamps at the
mill.
"(c) The mine manager to try three prospects, forenoon and afternoon
of each day, from the dumps of each of the four classes and record in
a book to be kept for that purpose the estimated mill yield of each
one.
"(d) The mill manager was required to do the same at the mill and keep
his record.
"(e) There were four underground bosses in each shift, twelve in all.
I had a book fixed at the top of the shaft in which I required each of
these men, at the expiry of every shift, to record any change in the
faces of the quartz and particularly in regard to quality.
"(f) Having divided the ore into four classes I instructed the
amalgamators, of which there were two in each shift, six in all, that
I required the amalgam from each to be kept separate, with the object
of ascertaining what each part of the mine produced.
"(g) I procured padlocks for the covering boards of the mercury tables
and gave the keys to the amalgamators with instructions that they were
not to hand them over to any one except the exchange shift without my
written authority, and instructed them that they should clean down the
plates every three hours, and after cleaning down the amalgam, buckets
to be placed in the cleaning room, which I instructed to be kept
locked and the key in charge of the watchman night and day.
"(h) The whole of the amalgam taken from the plates during each
twenty-four hours to be cleaned and squeezed by the two amalgamators
on duty every forenoon at nine o'clock in the presence of the mill
manager, who should weigh each lot and enter it in a book to be kept
for the purpose, and the entry to be signed by the mill manager and
both amalgamators as witnesses.
"(i) Every alternate Friday the mortars (boxes) to be cleaned out; the
work to be commenced punctually at eight A.M. by the six amalgamators
in the presence of the mill manager, assisted by the three amalgam
cleaning room watchmen and the four battery feeders on duty,
prohibiting any of them from leaving until the cleaning up was
finished, and the amalgam cleaned, squeezed and weighed, and the
amount entered by the mill manager in the record look and attested by
the amalgamators.
"I think the intelligent readers (particularly those with a knowledge
of the business) will see the drift of the above regulations, viz.,
for there to be any peculation the whole of the battery staff--
fourteen in all--would have to participate in it, and the number was
too many to keep a secret. Formerly the amalgam cleaning room was
sacred to the mill manager, and on announcing to that official the new
instructions he at once tendered his resignation in a tone of offended
dignity, immediately followed by that of the mine manager. It is a
significant fact that shortly afterwards these two officials purchased
a large mill and other property at a cost of ten thousand pounds, and
that the mine yielded for the following three years during which I was
connected with it an average of over 17 dwt. to the ton, as against
formerly 10 to 12 dwt.
"The reader must draw his own conclusions. I used to make it a
practice to visit the mine daily and prospect the ore, and having the
mine and mill managers' daily prospecting as a guide as well as my
own, every man at the mill knew it was impossible for them to thieve
without my detecting it; moreover, I made it a rule to discharge any
of the mill employees that I discovered were interested in any small
private claims.
"The crux of the whole thing is having a practical miner at the head
of affairs, and it is impossible for him to thieve if the work is
carried out in the manner I have described."
To bring the whole matter to a conclusion. It may be taken as a safe
axiom that to make gold mining in the mine as distinct from mining on
the Stock Exchange really profitable the same system of economy, of
practical supervision, and scientific knowledge which is now adopted
in all other businesses must be applied to the raising and extraction
of the metal. Then, and not till then, will genuine mining take the
place to which it is entitled amongst our industries.
CHAPTER XI
RULES OF THUMB
This chapter has been headed as above because a number of the rules
and recipes given are simply practical expedients, not too closely
scientific. My endeavour has been to supply practical and useful
information in language as free from technicalities as possible, so as
to adapt it to the ordinary miner, mill operator and prospector, many
of whom have had no scientific training. Some of the expedients are
original devices educed by what we are told is the mother of
inventions; others are hints given by practical old prospectors who
had met with difficulties which would be the despair of a man brought
up within reach of forge, foundry, machine shop, or tradesmen
generally. There are many highly ingenious and useful contrivances
besides these I have given.
LIVING PLACES
The health of the prospector, especially in a new country, depends
largely on his housing--in which particular many men are foolishly
careless, for although they are aware that they will be camped out for
long periods, yet all the shelter they rely on is a miserable calico
tent, often without a "fly," while in some cases they sometimes even
sleep on the wet, or dusty, ground. Such persons fully deserve the ill
health which sooner or later overtakes them. A little forethought and
very moderate ingenuity would render their camp comparatively healthy
and comfortable.
In summer the tent is the hottest, and in winter the coldest of
domiciles. The "pizie" or "adobie" hut, or, where practicable, the
"dugout," are much to be preferred, especially the latter. "Pizie" or
"adobie" is simply surface soil kneaded with water and either moulded
between boards like concrete, to construct the walls, or made into
large sun-dried bricks. Salt water should not be used, as it causes
the wall to be affected by every change of weather. A properly
constructed house of this material, where the walls are protected by
overhanging eaves, are practically everlasting, and the former have
been standing for centuries. There are buildings of pizie or adobie in
Mexico, California and Australia which are as good as new, although
the latter were built nearly a century ago.
Adobie dwellings are warm in winter and cool in summer, and can be
kept clean and healthy by occasional coatings of lime whitewash.
The dugout is even more simple in construction. A cutting, say ten
feet wide, is put into the base of a hill for say twelve feet until
the back wall is, say, ten feet high, the sides starting from nothing
to that height. The front and such portion as is required of the side
walls are next constructed of pizie or rough stone, with mud mortar,
and the roof either gabled or skillion of bough, grass, or reed
thatch, and covered with pizie, over which is sometimes put another
thin layer of thatch to prevent the pizie being washed away by heavy
rain. Nothing can be more snug and comfortable than such a house,
unless the cows, as Mark Twain narrates, make things "monotonous" by
persistently tumbling down the chimney.
When the Burra copper mines were in full work in Australia, the banks
of the Burra Creek were honeycombed like a rabbit warren with the
"dugout homes" of the Cornish miners. The ruins of these old dugouts
now extend for miles, and look something like an uncovered Pompeii.
When water is scarce and the tent has to be retained, much can be done
to make the camp snug. I occupied a very comfortable camp once, of
which my then partner, a Dane, was the architect. We called it "The
Bungalow," and it was constructed as follows: First we set up our
tent, 10 ft. by 8 ft., formed of calico, but lined with green baize,
and covered with a well set fly.
Next we put in four substantial forked posts about 10 ft. high and 15
ft. apart, with securely fixed cross pieces, and on the top was laid a
rough flat roof of brush thatch; the sides were then treated in the
same way, but not so thickly, being merely intended as a breakwind.
The tent with its two comfortable bunks was placed a little to one
side, the remaining space being used as a dining and sitting room all
through the summer. Except in occasional seasons of heavy rain, when
we were saved the trouble of washing our dishes, the tent was only
used for sleeping purposes, and as a storehouse for clothes and
perishable provisions. I have "dwelt in marble halls" since then, but
never was food sweeter or sleep sounder than in the old bush bungalow.
A BUSH BED
To make a comfortable bush bedplace, take four forked posts about 3
ft. 6 in. long and 2 to 3 in. in diameter at the top; mark out your
bedplace accurately and put a post at each corner, about 1 ft. in the
ground. Take two poles about 7 ft. long, and having procured two
strong five-bushel corn sacks, cut holes in the bottom corners, put
the poles through, bringing the mouths of the sacks together, and
secure them there with a strong stitch or two. Put your poles on the
upright forked sticks, and you have a couch that even Sancho Panza
would have envied. It is as well to fix stretchers or cross stays
between the posts at head and foot.
In malarial countries, sleeping on the ground is distinctly dangerous,
and as such districts are usually thickly timbered, the Northern
Territory hammock is an admirable device, more particularly where
mosquitoes abound.
NORTHERN TERRITORY HAMMOCK
This hammock, which is almost a standing bedplace when rigged, is
constructed as follows:--To a piece of strong canvas 7 feet long and 2
1/2 feet wide, put a broad hem, say 3 1/2 inches wide at each end.
Into this hem run a rough stick, about 2 feet 8 inches by 2 inches
diameter. Round the centre of the stick pass a piece of strong three-
quarter inch rope, 8 to 10 feet long and knot it, so as to leave a
short end in which a metal eye is inserted. To each end of the two
sticks a piece of quarter-inch lashing, about 6 feet long, is securely
attached.
To make the mosquito covering take 18 feet of ordinary strong cheese
cloth, and two pieces of strong calico of the same size as the canvas
bed; put hems in the ends of the upper one large enough to take half-
inch sticks, to all four extremities of which 8 feet of whipcord is to
be attached. The calico forms the top and bottom of what we used to
call the "meat safe," the sides being of cheese cloth. A small,
flapped opening is left on the lower side. When once inside you are
quite safe from mosquito bites.
To rig the above, two trees are chosen 7 to 8 feet apart, or two
stayed poles can be erected if no trees are available. The bed is
rigged about 3 feet from the ground by taking the rope round the trees
or poles, and pulling the canvas taut by means of the metal eyelet.
Then the lashings at the extremities of the sticks are fixed about 3
feet further up the trees and you have a bed something between a
hammock and a standing bed. The mosquito net is fixed above the
hammock in a similar manner, except that it does not require the
centre stay.
An old friend of mine once had a rather startling experience which
caused him to swear by the Northern Territory hammock. He was camped
near the banks of a muddy creek on the Daly River, and had fortunately
hung his "meat safe" about four feet high. The night was very dark,
and some hours after retiring he heard a crash among his tin camp
utensils, and the noise of some animal moving below him. Thinking his
visitor was a stray "dingo," or wild dog, he gave a yell to frighten
the brute away, and hearing it go, he calmly went to sleep again. Had
he known who his caller really was, he would not have felt so
comfortable. In the morning on the damp ground below, he found the
tracks of a fourteen foot alligator, which was also out prospecting,
but which, fortunately, had not thought of investigating the "meat
safe."
PURIFYING WATER
There is not a more fertile disease distributor, particularly in a new
country, than water. The uninitiated generally take it for granted
that so long as water looks clear it is necessarily pure and
wholesome; as a matter of fact the contrary is more usually the case,
except in very well watered countries, and such, as a rule, are not
those in which gold is most plentifully got by the average prospector.
I have seen foolish fellows, who were parched with a long tramp, drink
water in quantity in which living organisms could be seen with the
naked eye, without taking even the ordinary precaution of straining it
through a piece of linen. If they contracted hydatids, typhoid fever,
or other ailments, which thin our mining camps of the strong, lusty,
careless youths, who could wonder?
The best of all means of purifying water from organic substances is to
boil it. If it be very bad, add carbon in the form of the charcoal
from your camp fire. If it be thick, you may, with advantage, add a
little of the ash also.
I once rode forty-five miles with nearly beaten horses to a native
well, or rock hole, to find water, the next stage being over fifty
miles further. The well was found, but the water in it was very bad;
for in it was the body of a dead kangaroo which had apparently been
there for weeks. The wretched horses, half frantic with thirst, did
manage to drink a few mouthfuls, but we could not. I filled our
largest billycan, holding about a gallon, slung it over the fire and
added, as the wood burnt down, charcoal, till the top was covered to a
depth of two inches. With the charcoal there was, of course, a little
ash containing bi-carbonate of potassium. The effect was marvellous.
So soon as the horrible soup came to the boil, the impurities
coagulated, and after keeping it at boiling temperature for about half
an hour, it was removed from the fire, the cinders skimmed out, and
the water allowed to settle, which it did very quickly. It was then
decanted off into an ordinary prospector's pan, and some used to make
tea (the flavour of which can be better imagined than described); the
remainder was allowed to stand all night, a few pieces of charcoal
being added. In the morning it was bright, clear, and absolutely
sweet. This experience is worth knowing as many a bad attack of
typhoid and other fevers would be averted if practical precautions of
this kind were only used.
TO OBTAIN WATER FROM ROOTS
The greatest necessity of animal life is water. There are, however,
vast areas of the earth's surface where this most precious element is
lamentably lacking, and such, unfortunately, is the case in many rich
auriferous districts.
To the practical man there are many indications of water. These, of
course, vary in different countries. Sometimes it is the herbage, but
probably, the best of all is the presence of carnivorous animals and
birds. These are never found far from water. In Australia the not
over-loved wily old crow is a pretty sure indicator of water within
reasonable distance--water may be extracted from the roots of the
Mallee (/Eucalyptus dumosa/ and /gracilis/)--the Box (/Eucalyptus
hemiphloia/) and the Water Bush (/Hakea leucoptera/). To extract it
the roots are dug up, cut into lengths of about a foot, and placed
upright in a can; the lower ends being a few inches above the bottom.
It is simply astonishing how much wholesome, if at times somewhat
astringent, water may thus be obtained in a few hours, particularly at
night.
/Hakea leucoptera/. "Pins and needles."--Maiden, in his work "Useful
Native Plants of Australia," says: "In an experiment on a water-
yielding /Hakea/, the first root, about half an inch in diameter and
six or eight feet long, yielded quickly, and in large drops about a
wine-glass full of really excellent water."
This valuable, though not particularly ornamental shrub (for it never
attains to the dimensions of a tree), is found, to the best of my
belief, in all parts of Australia, although it is said to be absent
from West Australia. As to this I don't feel quite sure. I have seen
it "from the centre of the sea" as far west as Streaky Bay, and
believe I have seen it further West still. Considering the great
similarity of much of the flora of South Africa to that of Australia,
it is probable that some species of the water-bearing /Hakea/ might be
found there. It can readily be recognised by its acicular, needle-like
leaves, and more particularly by its peculiarly shaped seed vessel,
which resembles the pattern on an old-fashioned Indian shawl.
If the water found is too impure for drinking purposes and the trouble
arises from visible animalculae only, straining through a pocket-
handkerchief is better than nothing; the carbon filter is better
still; but nothing is so effective as boiling. A carbon filter is a
tube with a wad of compressed carbon inserted, through which the water
is sucked, but as a rule clay-coloured water is comparatively
innocuous, but beware of the bright, limpid water of long stagnant
rock water-holes.
TO MAKE AN EFFECTIVE FILTER
Take a nail-can, keg, cask, or any other vessel, or even an ordinary
wooden case (well tarred inside, if possible, to make it water-tight).
Make a hole or several holes in the bottom, and set it over a tank or
bucket. Into the bottom of the filter put (1) a few inches of washed
broken stone; (2) about four inches of charcoal; (3) say three inches
of clean coarse sand (if not to hand you can manufacture it by
crushing quartz with your pestle and mortar), and (4) alternate layers
of charcoal and sand until the vessel is half filled. Fill the top
half with water, and renew from time to time, and you have a filter
which is as effective as the best London made article. /But it is
better to boil your water whether you filter afterwards or not./
Clear the inside of the water-cask frequently, and occasionally add to
the water a little Condy's fluid, as it destroys organic matter. A
useful cement for stopping leaky places in casks is made as follows:
Tallow 25 parts, lard 40 parts, sifted wood ash 25 parts. Mix together
by heating, and apply with a knife blade which has just been heated.
CANVAS WATER BAGS
Are easily made, and are very handy for carrying small supplies of
drinking-water when prospecting in a dry country; they have the
advantage of keeping the water cool in the hottest weather, by reason
on the evaporation. The mouthpiece is made of the neck of a bottle
securely sewn in.
MEDICINE CASE
Medicine is also a matter well worthy of thought. The author's worst
enemy would not call him a mollycoddle, yet he has never travelled in
far wilds without carrying something in the way of medicine. First,
then, on this subject, it cannot be too often reiterated that if
common Epsom salts were a guinea an ounce instead of a penny the
medicine would be valued accordingly, but it is somewhat bulky. What I
especially recommend, however, is a small pocket-case of the more
commonly known homeopathic remedies, "Mother tinctures," which are
small, light, and portable, with a small simple book of instructions.
Though generally an allopath in practice, I once saved my own life,
and have certainly helped others by a little knowledge in diagnosing
complaints and having simple homeopathic remedies at hand to be used
in the first stages of what might otherwise have been serious
illnesses.
PRODUCING FIRE
Every one has heard, and most believe, that fire may be easily
produced by rubbing together two pieces of wood. I have seen it done
by natives, but they seldom make use of the operation, which is
generally laborious, preferring to carry lighted fire sticks for
miles. I have never succeeded in the experiment.
Sometimes, however, it is almost a matter of life or death to be able
to produce fire. The back of a pocket knife, or an old file with a
fragment of flint, quartz, or pyrites struck smartly together over the
remains of a burnt piece of calico, will in deft hands produce a spark
which can be fanned to a glow, and so ignite other material, till a
fire is produced.
Also it may not be generally known that he who carries a watch carries
a "burning glass" with which he can, in clear weather, produce fire at
will. All that is required is to remove the glass of your watch and
carefully three parts fill it with water (salt or fresh). This forms a
lens which, held steadily, will easily ignite any light, dry,
inflammable substance.
When firearms are carried, cut a cartridge so that only about a
quarter of the charge of powder remains. Damp some powder and rub it
on a small piece of dry cotton cloth or well-rubbed brown paper. Push
a loose pellet of this into the barrel, insert your half cartridge,
fire at the ground, when the wad will readily ignite, and can be blown
into flame.
TO COPY CORRESPONDENCE
The prospector is not usually a business man; hence in dealing with
business men who, like Hamlet, are "indifferent honest," he frequently
comes to grief through not having a copy of his correspondence. It is
most desirable, therefore, either to carry a carbon paper duplicating
book and a stylus, or by adding a little sugar to good ordinary black
ink you may make a copying ink; then with the aid of a "yellow back"
octavo novel, two pieces of board, and some ordinary tissue paper, you
may take a copy of any letter you send.
TO PROVIDE A SIMPLE TELEGRAPHIC CODE
Buy a couple of cheap small dictionaries of the same edition, send one
to your correspondent with an intimation that he is to read up or down
so many words from the one indicated when receiving a message. Thus,
if I want to say "Claim is looking well," I take a shilling
dictionary, send a copy to my correspondent with the intimation that
the real word is seven down, and telegraph--"Civilian looking weird;"
this, if looked up in Worcester's little pocket dictionary, for
instance, will read "Claim looking well." Any dictionary will do, so
long as both parties have a copy and understand which is the right
word. By arrangement this plan can be varied from time to time if you
have any idea that your code can be read by others.
A SERVICEABLE SOAP
Wood ashes from the camp fire are boiled from day to day in a small
quantity of water, and allowed to settle, the clear liquid being
decanted off. When the required quantity of weak lye has been
accumulated, evaporate by boiling, till a sufficient degree of
strength has been obtained. Now melt down some mutton fat, and, while
hot, add to the boiling lye. Continue boiling and stirring till the
mixture is about the consistency of thick porridge, pour into any
convenient flat vessel, and let it stand till cool. If you have any
resin in store, a little powdered and added gradually to the melting
tallow, before mixing with the lye, will stiffen your soap.
TO CROSS A FLOODED STREAM
Take a half-gallon, or larger, tin "billy can," enclose it in a strong
cotton handkerchief or cotton cloth, knotting same over the lid,
invert, and, taking the knot in the hand, you have a floating
appliance which will sustain you in any water, whether you are a
swimmer or not. The high silk hat of civilisation would act as well as
the can, but these are not usually found far afield.
TO MAKE A HIDE BUCKET
At times when prospecting in an "incline" or "underlay" shaft,
particularly where the walls of the lode are irregular, a hide bucket
will be found preferable to an iron one. The mode of manufacture is as
follows: Procure an ox hide, "green," if possible; if dry, it should
be soaked until quite soft. Cut some thin strips of hide for sewing or
lacing. Now shape a bag or pocket of size sufficient to hold about a
hundredweight of stone, and by puncturing the edges with a knife,
marline-spike, or other pointed tool, sew together; make a handle of
twisted or pleated hide, and having filled your bucket with dry sand
or earth let it stand till the whole is quite dry, when it will be
properly distended and will maintain its shape until worn out.
TO MAKE A "SLUSH LAMP"
Where candles are scarce and kerosine is not, a "slush lamp" is a
useful substitute. Take an old but sound quart tin pannikin, half fill
it with sand or earth, and prepare a thin stick of pine, round which
wrap a strip of soft cotton cloth. The stick should be about half an
inch longer than the depth of the pannikin. Melt some waste fat, fill
the pannikin therewith, push the stick down into the earth at the
bottom, and you have a light, which, if not equal to the electric or
incandescent gas burner, is quite serviceable. In Australia the soft
velvety core of the "bottle brush," /Banksia marginata/, is often used
instead of the cotton wick.
CHAPTER XII
RULES OF THUMB
MINING APPLIANCES AND METHODS
A TEMPORARY FORGE
What prospector has not at times been troubled for the want of a
forge? To steel or harden a pick or sharpen a drill is comparatively
easy, but there is often a difficulty in getting a forge. Big single
action bellows are sometimes bought at great expense, and some
ingenious fellows have made an imitation of the blacksmith's bellows
by means of sheepskins and rough boards.
With inadequate material and appliances to hand, the following will be
found easier to construct and more lasting when constructed. Only a
single piece of iron is required, and, at a pinch, one could even
dispense with that by using a slab of talcose material, roughly
shaping a hearth therein and making a hole for the blast. First,
construct a framing about the height of an ordinary smith's forge.
This can made with saplings and bark, or better still, if available,
out of an empty packing case about three feet square. Fill the frame
or case with slightly damped earth and ram it tight, leaving the usual
hollow hearth. Then form a chamber below the perforated hearth opening
to the rear. Now construct a centrifugal fan, such as is used for the
ventilation of shallow shafts and workings. Set this up behind the
hearth and revolve by means of a wooden multiplying wheel. A piece of
ordinary washing line rope, or sash line rope, well resined if resin
can be got--but pitch, tar, or wax will do by adding a little fine
dust to prevent sticking--is used as a belt. With very rough materials
a handy man can thus make a forge that will answer ordinary
requirements.--N.B. Do not use clay for your hearth bed unless you can
get a highly aluminous clay, and can give it full time to dry before
the forge fire is lit. Ordinary surface soil, not too sandy, acts
well, if damped and rammed thoroughly. Of course, if you can get an
iron nozzle for your blower the whole operation is simplified.
SIMPLE WAY OF MAKING CHARCOAL
Dig a pit 5 feet square by 3 feet deep and fill with fuel. After
lighting, see that the pit is kept full. The hot embers will gradually
sink to the bottom. The fuel should be kept burning fiercely until the
pit seems almost full, when more fuel should be added, raising the
heap about a foot above the level of the ground. The earth dug out of
the pit should then be shovelled back over the burning mass. After
leaving it to cool for 24 hours the pit will be found nearly full of
charcoal. About one-quarter the weight of the dry fuel used should be
recovered in charcoal.
ROUGH SMELTING ON THE MINE
Rough smelting on the mine is effected with a flux of borax, carbonate
of soda, or, as I have often done, with some powdered white glass.
When the gold is smelted and the flux has settled down quietly in a
liquid state, the bulk of the latter may be removed, to facilitate
pouring into the mould, by dipping an iron rod alternately into the
flux and then into a little water, and knocking off the ball of
congealed flux which adheres after each dip. This flux should,
however, be crushed with a pestle and mortar and panned off, as, in
certain cases, it may contain tiny globules of gold.
MISFIRES IN BLASTING
One of the most common sources of accident in mining operations is due
either to carelessness or to the use of defective material in
blasting. A shot misses, generally for one of two reasons; either the
explosive, the cap, or the fuse (most often the latter), is inferior
or defective; or the charging is incompletely performed. Sometimes the
fuse is not placed properly in the detonator, or the detonator is not
properly enclosed in the cartridge, or the fuse is injured by improper
tamping. If several shots have been fired together, particularly at
the change of a "shift," the men who have to remove the broken
material may in so doing explode the missed charge. Or, more
inexcusable still, men will often be so foolish as to try to clear out
the drill hole and remove the missed cartridge. When a charge is known
to have missed all that is necessary to do in order to discharge it
safely is to remove a few inches of "tamping" from the top of the
drill hole, place in the bore a plug of dynamite with cap and fuse
attached, put an inch or two of tamping over it and fire, when the
missed charge will also be exploded. Of course, judgment must be used
and the depth of the drill taken into consideration. As a rule, miners
use far more tamping than is at all requisite. The action of the
charge will generally be found quite as effective with a few inches of
covering matter as with a foot or more, while the exploding of misfire
cartridges is rendered simple, as no removal of tamping is required
before placing the top "plug" in case of misfire.
TO PREVENT LOSS OF RICH SPECIMENS IN BLASTING
When blasting the cap of a lode, particularly on rich shutes of gold,
the rock is apt to fly, and rich specimens may be thrown far afield
and so be lost. A simple way of avoiding this is to procure a quantity
of boughs, which tie into loose bundles, placing the leafy parts
alternately end for end. Before firing, pile these bundles over the
blast and, if care is used, very few stones will fly. The same device
may be used in wide shallow shafts.
A SIMPLE MODE OF RETORTING SMALL QUANTITIES OF AMALGAM
Clean your amalgam and squeeze it as hard as possible through strong
calico or chamois leather. Take a large sound potato, cut off about a
quarter from one end and scoop out a hole in the centre about twice as
big as the ball of amalgam. Procure a piece of flat iron--an old spade
will do as well as anything--insert the amalgam, and, having placed
the potato, cut side downwards, thereon, put the plate of iron on the
forge, heat up first gently, then stronger, till separation has taken
place, when the gold will be found in a bright clean button on the
plate and the mercury in fine globules in the potato, from which it
can be re-collected by breaking up the partly or wholly cooked tuber
under water in an enamelled or ordinary crockery basin.
TO RETORT SMALL QUANTITIES OF MERCURY FOR AMALGAMATING ASSAY TESTS
Get two new tobacco pipes similar in shape, with the biggest bowls and
longest stems procurable. Break off the stem of one close to the bowl
and fill the hole with well worked clay (some battery slimes make the
best luting clay). Set the stemless pipe on end in a clay bed, and
fill with amalgam, pass a bit of thin iron or copper wire beneath it,
and bend the ends of the wire upwards. Now fit the whole pipe, bowl
inverted, on to the under one, luting the edges of both well with
clay. Twist the wire over the top with a pair of nippers till the two
bowls are fitted closely together, and you have a retort that will
stand any heat necessary to thoroughly distil mercury.
A SIMPLE MODE OF ASCERTAINING THE NOMINAL HORSE-POWER OF AN ENGINE
Multiply the internal diameter of the cylinder by itself and strike off
the last figure of the quotient. The diameter is
20" X 20"
20
___
400. The H.P. is 40.
The following rules will be found more professionally accurate from an
engineering standpoint, though the term "horse-power" is not now
generally employed.
/To find the Nominal Horse-power/.--For /non-condensing/ engines:
Multiply the square of the diameter of the cylinder in inches by 7 and
divide the product by 80. For /condensing/ engines: Multiply the
square of the diameter of the cylinder in inches by 7 and divide the
product by 200.
/To find the Actual Horse-power/ of an engine, multiply the area of
the cylinder in square inches by the average effective pressure in
pounds per square inch, less 3 lb. per square inch as the frictional
allowance, and also by the speed of the piston in feet per minute,
dividing the product by 33,000, and the quotient will be the actual
horse-power.
"SCALING" COPPER PLATES
To "scale" copper plates they may be put over a charcoal or coke fire
to slowly sublimate the quicksilver. Where possible, the fireplace of
a spare boiler can be utilised, using a thin red fire. After the
entire evaporation of the quicksilver the plates should be slowly
cooled, rubbed with hydrochloric acid, and put in a damp place
overnight, then rubbed with a solution of sal ammoniac and nitre in
equal parts, and again heated slowly over a red fire. They must not be
allowed to get red hot; the proper degree of heat is indicated by the
gold scale rising in blisters, when the plates should be taken from
the fire and the gold scraped off. Any part of the plate on which the
gold has not blistered should be again rubbed with the solution and
fired. The gold scale should be collected in a glass or earthen dish
and covered with nitric acid, till all the copper is dissolved, when
the gold can be smelted in the usual way; but after it is melted
corrosive sublimate should be put in the crucible till a blue flame
ceases to be given off.
/A Second Method/
The simplest plan I know is to have a hole dug nine inches deep by
about the size of the plate to be scaled; place a brick at each
corner, and on each side, halfway between, get up a good fire; let it
burn down to strong embers, or use charcoal, then place the plate on
three bars of iron extending between the three pairs of bricks, have a
strong solution of borax ready in which soak strips of old "table
blanket," laying these over the plate and sprinkling them with the
borax solution when the plate gets too hot. After a time the deposit
of mercury and gold on the plate will assume a white, efflorescent
appearance, and may then be readily parted from the copper.
/Another Method/
Heat the plate over an open fire, to drive off the mercury; after
which, let it cool, and saturate with dilute sulphuric acid for three
hours, or longer; then sprinkle over the surface a mixture of equal
parts of common salt and sal ammoniac, and heat to redness; then cool,
and the gold scale comes off freely; the scale is then boiled in
nitric or sulphuric acid, to remove the copper, previous to melting.
Plates may be scaled about once in six months, and will under ordinary
circumstances produce about one ounce of clean gold for each
superficial foot of copper surface employed. I always paint the back
of the plate with a mixture of boiled oil and turpentine, or beeswax
dissolved in turpentine, to prevent the acid attacking the copper.
HOW TO SUPPLY MERCURY TO MORTAR BOXES
I am indebted for the following to Mr. J. M. Drake, who, speaking of
his experience on the Wentworth Mine, N.S.W., says:
"Fully 90 per cent of the gold is saved on the outside plates, only a
small quantity remaining in the mortar. The plates have a slope of 2
in. to 1 ft. No wells are used, the amalgam traps saving any
quicksilver which may leach off the plates. The quicksilver is added
every hour in the mortar. The quantity is regulated by the mill
manager in the following manner: Three pieces of wood, 8 in. wide by
12 in. long by 2 in. thick, have 32 holes 1 in. deep bored in each of
them. These holes will just take a small 2 oz. phial. The mill manager
puts the required quantity of quicksilver in each bottle and the
batteryman empties one bottle in each mortar every hour; and puts it
back in the hole upside down. Each block of wood lasts eight hours,
the duration of one man's shift." This of course is for a 20-head mill
with four mortars or "boxes."
I commend this as an excellent mode of supplying the mercury to the
boxes or mortars. The quantity to be added depends on circumstances. A
careless battery attendant will often put in too much or too little
when working without the automatic feeder. I have known an attendant
on suddenly awaking to the fact half through his shift, that he had
forgotten to put in any mercury, to then empty into the stamper box
two or three pounds weight; with what effect may be easily surmised.
HOW WATER SHOULD ENTER STAMPER BOXES
The following extract which relates to Californian Gold Mill practices
is from Bulletin No. 6 of the California State Mining Bureau. I quite
agree with the practice.
"The battery water should enter both sides of the mortar in an even
quantity, and should be sufficient to keep a fairly thick pulp which
will discharge freely through the grating or screen. About 120 cubic
feet of water per ton of crushed ore may be considered an average, or
8 to 10 cubic feet per stamp per hour.
"Screens of different materials and with different orifices are used;
the materials comprise wire cloth of brass or steel, tough Russian
sheet iron, English tinned plate, and, quite recently, aluminium
bronze. The 'aluminium bronze' plates are much longer lived than
either of the other kinds, and have the further advantage that, when
worn out, they can be sold for the value of the metal for remelting;
these plates are bought and sold by the pound, and are said to contain
95 per cent of copper and 5 per cent of aluminium. Steel screens are
not so much used, on account of their liability to rust."
I have had no experience with the aluminium bronze screen. I presume,
however, that it is used only for mills where mercury is not put in
the mortars, otherwise, it would surely become amalgamated. The same
remark applies to brass wire cloth and tinned plate. Unless the metal
of which they are composed will not readily amalgamate with mercury, I
should be chary of using new screen devices. Mercury is a most
insidious metal and is often found most unexpectedly in places in the
battery where it should not be. Probably aluminium steel would be
better than any substance mentioned. It would be hard, light, strong,
and not readily corrodible. I am not aware if it has been tried.
Under the heading of "Power for Mills" the following is taken from the
same source.
POWER FOR MILLS
"As the Pelton wheel seems to find the most frequent application in
California, it may be convenient for millmen to have the following
rule, applicable to these wheels:
"When the head of water is known in feet, multiply it by 0.0024147,
and the product is the horse-power obtainable from one miner's inch of
water.
"The power necessary for different mill parts is:
For each 850lb. stamp, dropping 6 in. 95 times per minute, 1.33 h.-p.
For each 750lb. stamp, dropping 6 in. 95 times per minute, 1.18 h.-p.
For each 650lb. stamp, dropping 6 in. 95 times per minute, 1.00 h.-p.
For an 8-inch by 10-inch Blake pattern rock-breaker 9.00 h.-p.
For a Frue or Triumph vanner, with 220 revolutions per min. 0.50 h.-p.
For a 4-feet clean-up pan, making 30 revolutions per min. 1.50 h.-p.
For an amalgamating barrel, making 30 revolutions per min. 2.50 h.-p.
For a mechanical batea, making 30 revolutions per min. 1.00 h.-p."
The writer has had small practical experience of the working of that
excellent hydraulic motor, the Pelton wheel, but if by horse-power in
the table given is meant nominal horse-power, it appears to be high.
Working with 800 cwt. stamps, 80 blows a minute, one horse-power
nominal will be found sufficient with any good modern engine, which
has no further burden than raising the stamps and pumping the feed
water. It is always well, however, particularly when providing engine
power, to err on the right side, and make provision for more than is
absolutely needed for actual battery requirements. This rule applies
with equal potency to pumping engines.
TO AVOID LOSS IN CLEANING UP
The following is a hint to quartz mill managers with respect to that
common source of loss of gold involved in the almost inevitable loss
of mercury in cleaning up operations. I have known hundreds of pounds'
worth of gold to be recovered from an old quartz mill site by the
simple process of washing up the ground under the floor.
If you cannot afford to floor the whole of the battery with smooth
concrete, at all events smoothly concrete the floor of the cleaning-up
room, and let the floor slope towards the centre: where a sink is
provided. Any lost mercury must thus find its way to the centre, where
it will collect and can be panned off from time to time. Of course an
underground drain and mercury trap must be provided.
IRON EXTRACTOR
When using self-feeders, fragments of steel tools are especially
liable to get into the battery boxes or other crushing appliance where
they sometimes cause great mischief. I believe the following plan
would be a practicable remedy for this evil.
By a belt from the cam or counter shaft, cause a powerful electric
magnet to extract all magnetic particles; then, by a simple ratchet
movement, at intervals withdraw the magnet and drop the adhering
fragments into a receptacle by automatically switching off the
electric current. A powerful ordinary horseshoe magnet might probably
do just as well, but would require to be re-magnetised from time to
time.
TO SILVER COPPER PLATES
To silver copper plates, that is, to amalgamate them on the face with
mercury, is really a most simple operation, though many batterymen
make a great mystery of it. Indeed, when I first went into a quartz
mill the process deemed necessary was not only a very tedious one, but
very dirty also.
To amalgamate with silver, in fact, to silver-plate your copper
without resort to the electro-plating bath, take any old silver
(failing that, silver coin will do, but is more expensive), and
dissolve it in somewhat dilute nitric acid, using only just sufficient
acid as will assist the process. After some hours place the ball of
amalgam in a piece of strong new calico and squeeze out any surplus
mercury.
About an ounce of silver to the foot of copper is sufficient. To apply
it on new plates use nitric acid applied with a swab to free the
surface of the copper from oxides or impurities, then rub the ball of
amalgam over the surface using some little force. It is always well
when coating copper plates with silver or zinc by means of mercury to
let them stand dry for a day or two before using, as the mercury
oxidises and the coating metal more closely adheres.
Only the very best copper plate procurable should be used for battery
tables; bad copper will always give trouble, both in the first
"curing," and after treatment. It should not be heavily rolled copper,
as the more porous the metal the more easily will the mercury
penetrate and amalgamate. I cannot agree that any good is attained by
scouring the plates with sand and alkalies, as recommended in some
books on the subject; on the contrary, I prefer the opposite mode of
treatment, and either face the plates with nitrate of silver and
nitrate of mercury, or else with sulphate of zinc and mercury, in the
form of what is called zinc amalgam. If mine water, which often
contains a little free sulphuric acid, is being used, the latter plan
is preferable.
The copper should be placed smoothly on the wooden table and secured
firmly thereto by copper tacks. If the plate should be bent or
buckled, it may be flattened by beating it with a heavy hammer, taking
care to interpose a piece of inch-thick soft wood between hammer and
plate.
To coat with mercury only, procure some nitrate of mercury. This is
easily made by placing mercury in an earthenware bowl, pouring
somewhat dilute nitric acid on it, and letting it stand till the
metallic mercury is changed to a white crystal. Dense reddish-brown
fumes will arise, which are injurious if breathed, so the operation
should be conducted either in the open air, or where there is a
draught.
Having your silvering solution ready, which is to be somewhat diluted
with water, next take two swabs, with handles about 12 inches long,
dip the first into a basin containing dilute nitric acid, and rub it
rapidly over about a foot of the surface of the plate; the oxide of
copper will be absolutely removed, and the surface of the copper
rendered pure and bright; then take the other swab, wet with the
dilute nitric of mercury, and pass it over the clean surface, rubbing
it well in. Continue this till the whole plate has a coating of
mercury. It may be well to go over it more than once. Now turn on the
water and wash the plate clean, sprinkle with metallic mercury,
rubbing it upwards until the plate will hold no more.
A basin with nitrate of mercury may be kept handy, and the plates
touched up from time to time for a few days until they get amalgamated
with gold, after which, unless you have much base metal to contend
with, they will give no further trouble.
It must be remembered, however, that an excessive use of nitric acid
will result in waste of mercury, which will be carried off in a milky
stream with the water; and also that it will cause the amalgam to
become very hard, and less active in attracting other particles of
gold.
If you are treating the plate with nitrate of silver prepared as
already mentioned, clean the plate with dilute nitric acid, rub the
surface with the ball of amalgam, following with the swab and fairly
rubbing in. It will be well to prepare the plate some days before
requiring to use it, as a better adhesion of the silver and copper
takes place than if mercury is applied at once.
To amalgamate with zinc amalgam, clean the copper plate by means of a
swab, with fairly strong sulphuric acid diluted with water; then while
wet apply the zinc-mercury mixture and well rub in. To prepare the
zinc-amalgam, clip some zinc (the lining of packing cases will do)
into small pieces and immerse them in mercury after washing them with
a little weak sulphuric acid and water to remove any coating of oxide.
When the mercury will absorb no more zinc, squeeze through chamois
leather or calico (as for silver amalgam), and well rub in. The plate
thus prepared should stand for a few days, dry, before using. If,
before amalgamation with gold takes place, oxide of copper or other
scum should rise on this plate a little very dilute sulphuric acid
will instantly remove it.
Sodium and cyanide of potassium are frequently used in dressing-
plates, but the former should be very sparingly employed, as it will
often do more harm than good by taking up all sorts of base metals
with the amalgam, and so presenting a surface which the gold will pass
over without adhering to. Where water is scarce, and is consequently
used over and over again, lime may be added to the pulp, or, if lime
is not procurable, wood ashes may be used. The effect is two-fold; the
lime not only tends to "sweeten" sulphide ores and keep the tables
clean, but also causes the water to cleanse itself more quickly of the
slimes, which will be more rapidly precipitated. When zinc amalgam is
used, alkalies would, of course, be detrimental.
When no other water than that from the mine is available, difficulties
often arise owing to the impurities it contains. These are various,
but among the most common are the soluble sulphates, and sometimes
free sulphuric acid evolved by the oxidisation of metallic sulphides.
In the presence of this difficulty, do one of two things; either
/utilise/ or /neutralise/. In certain cases, I recommend the former.
Sometime since I was treating, for gold extraction, material from a
mine which was very complex in character, and for which I coined the
term "polysynthetic." This contained about half a dozen different
sulphides. The upper parts of the lode being partially oxidised, free
sulphuric acid (H2SO4) was evolved. I therefore, following out a
former discovery, added a little metallic zinc to the mercury in the
boxes and on the plates with excellent results. When the free acid in
the ore began to give out in the lower levels I added minute
quantities of sulphuric acid to the water from time to time. I have
since found, however, that with some water, particularly West
Australian, the reaction is so feeble (probably owing to the lime and
magnesia present) as to make this mode of treatment unsuitable.
HOW TO MAKE A DOLLY
I have seen some rather elaborate dollies, intended to be worked with
amalgamating tables, but the usual prototype of the quartz mill is set
up, more or less, as follows: A tree stump, from 9 in. to a foot
diameter, is levelled off smoothly at about 2 ft. from the ground; on
this is firmly fixed a circular plate of 1/2 in. iron, say 9 in. in
diameter; a band of 3/16 in. iron, about 8 or 9 in. in height, fits
more or less closely round the plate. This is the battery box. A beam
of heavy wood, about 3 in. diameter and 6 ft. long, shod with iron, is
vertically suspended, about 9 in. above the stump, from a flexible
sapling with just sufficient spring in it to raise the pestle to the
required height. About 2 ft. from the bottom the hanging beam is
pierced with an augur hole and a rounded piece of wood, 1 1/2 in. by
18 in., is driven through to serve as a handle for the man who is to
do the pounding. His mate breaks the stone to about 2 in. gauge and
feeds the box, lifting the ring from time to time to sweep off the
triturated gangue, which he screens through a sieve into a pan and
washes off, either by means of a cradle or simply by panning. In
dollying it generally pays to burn the stone, as so much labour in
crushing is thus saved. A couple of small kilns to hold about a ton
each dug out of a clay bank will be found to save fuel where firewood
is scarce, and will more thoroughly burn the stone and dissipate the
base metals, but it must be remembered that gold from burnt stone is
liable to become so encrusted with the base metal oxides as to be
difficult to amalgamate.
ROUGH WINDLASS
Make two St. Andrew's crosses with four saplings, the upper angle
being shorter than the lower; fix these upright, one at each end of
the shaft; stay them together by cross pieces till you have
constructed something like a "horse," such as is used for sawing wood,
the crutch being a little over 3 feet high. Select a leg for a
windlass barrel, about 6 in. diameter and a foot longer than the
distance between the supports, as straight as is procurable; cut in it
two circular slots about an inch deep by 2 in. wide to fit into the
forks; at one end cut a straight slot 2 in. deep across the face. Now
get a crooked bough, as nearly the shape of a handle as nature has
produced it, and trim it into right angular shape, fit one end into
the barrel, and you have a windlass that will pull up many a ton of
stuff.
PUDDLER
This is made by excavating a circular hole about 2 ft. 9 in. deep and,
say 12 ft. in diameter. An outer and inner wall are then constructed
of slabs 2 ft. 6 in. in height to ground level, the outer wall being
thus 30 ft. and the inner 15 ft. in circumference. The circular space
between is floored with smooth hardwood slabs or boards, and the whole
made secure and water-tight. In the middle of the inner enclosure a
stout post is planted, to stand a few inches above the wall, and the
surrounding space is filled up with clay rammed tight. A strong iron
pin is inserted in the centre of the post, on which is fitted a
revolving beam, which hangs across the whole circumference of the
machine and protrudes a couple of feet or so on each side. To this
beam are attached, with short chains, a couple of drags made like V-
shaped harrows by driving a piece of red iron through a heavy frame,
shaped as a rectangular triangle.
To one end of the beam an old horse is attached, who, as he slowly
walks round the circular track, causes the harrows and drags to so
puddle the washdirt and water in the great wooden enclosure that the
clay is gradually disintegrated, and flows off with the water which is
from time to time admitted. The clean gravel is then run through a
"cradle, "long Tom," or "sluice," and the gold saved. This, of course,
is the simplest form of gold mining. In the great alluvial mines other
and more intricate appliances are used but the principle of extraction
is the same.
A MAKESHIFT PUMP
To make a temporary small "draw-lift" pump, which will work down to a
hundred feet or more if required, take a large size common suction
Douglas pump, and, after removing the top and handle, fix the pump as
close to the highest level of the water in the shaft as can be
arranged. Now make a square water-tight wooden column of slightly
greater capacity than the suction pipe, fix this to the top of the
pump, and by means of wooden rods, work the whole from the surface,
using either a longer levered handle or, with a little ingenuity,
horse-power. If you can get it the iron downpipe used to carry the
water from the guttering of houses is more easily adapted for the pipe
column; then, also, iron pump rods can be used but I have raised water
between 60 and 70 feet with a large size Douglas pump provided only
with a wooden column and rods.
SQUEEZING AMALGAM
For squeezing amalgam, strong calico, not too coarse, previously
soaked in clean water, is quite as good as ordinary chamois leather.
Some gold is fine enough to escape through either.
MERCURY EXTRACTOR
The mercury extractor or amalgam separator is a machine which is very
simple in construction, and is stated to be most efficient in
extracting quicksilver from amalgam, as it requires but from two to
three minutes to extract the bulk of the mercury from one hundred
pounds of amalgam, leaving the amalgam drier than when strained in the
ordinary way by squeezing through chamois leather or calico. The
principle is that of the De Laval cream separator--i.e., rapid
centrifugal motion. The appliance is easily put together, and as
easily taken apart. The cylinder is made of steel, and is run at a
very high rate of speed.
The general construction of the appliance is as follows: The casing or
receiver is a steel cylinder, which has a pivot at the bottom to
receive the step for an upright hollow shaft, to which a second
cylinder of smaller diameter is attached. The second cylinder is
perforated, and a fine wire cloth is inserted. The mercury, after
passing through the cloth, is discharged through the perforations.
When the machine is revolved at great speed, the mercury is forced
into the outside cylinder, leaving the amalgam, which has been first
placed in a calico or canvas bag, in a much drier state than it could
be strained by hand. While not prepared to endorse absolutely all that
is claimed for this appliance, I consider that it has mechanical
probability on its side, and that where large quantities of amalgam
have to be treated it will be found useful and effective.
SLUICE PLATES
I am indebted to Mr. F. W. Drake for the following account of sluice
plates, which I have never tried, but think the device worth
attention:
"An addition has been made to the gold-saving appliances by the
placing of what are called in America, 'sluice plates' below the
ordinary table. The pulp now flows over an amalgamating surface, 14
ft. long by 4 ft. wide, sloping 1 1/2 in. to the foot, and is then
contracted into a copper-plated sluice 15 ft. long by 14 in. wide,
having a fall of 1 in. to the foot. Our mill manager (Mr. G. C. Knapp)
advocated these sluice plates for a long time before I would consent
to a trial. I contended that as we got little or no amalgam from the
lower end of our table plates there was no gold going away capable of
being recovered by copper plates; and even if it were, narrow sluice
plates were a step in the wrong direction. If anything the
amalgamating surface should be widened to give the particles of gold a
better chance to settle. His argument was that the conditions should
be changed; by narrowing the stream and giving it less fall, gold,
which was incapable of amalgamation on the wide plates, would be
saved. We finally put one in, and it proved so successful that we now
have one at the end of each table. The per-centage recovered on the
sluice plates, of the total yield, varies, and has been as follows:--
October, 9.1 per cent; November, 6.9 per cent; December, 6.4 per cent;
January, 4.3 per cent; February, 9.3 per cent."
MEASURING INACCESSIBLE DISTANCES
To ascertain the width of a difficult gorge, a deep river, or
treacherous swamp without crossing and measuring, sight a conspicuous
object at the edge of the bank on the farther side; then as nearly
opposite and square as possible plant a stake about five feet high,
walk along the nearer margin to what you guess to be half the distance
across (exactitude in this respect is not material to the result),
there plant another stake, and continuing in a straight line put in a
third. The stakes must be equal distances apart and as nearly as
possible at a right angle to the first line. Now, carrying in hand a
fourth stake, strike a line inland at right angles to the base and as
soon as sighting over the fourth stake, you can get the fourth and
second stakes and the object on the opposite shore in line your
problem is complete. The distance between No. 4 and No. 3 stakes is
the same as that between No. 1 and the opposite bank.
TO SET OUT A RIGHT ANGLE WITH A TAPE
Measure 40 ft. on the line to which you wish to run at right angles,
and put pegs at A and B; then, with the end of the tape held carefully
at A, take 80 ft., and have the 80 ft. mark held at B. Take the 50 ft.
mark and pull from A and B until the tape lies straight and even, you
will then have the point C perpendicular to AB. Continue straight
lines by sighting over two sticks in the well-known way.
/Another method/.--Stick a pin in each corner of a square board, and
look diagonally across them, first in the direction of the line to
which you wish to run at right angles, and then for the new line sight
across the other two pins.
A SIMPLE LEVELLING INSTRUMENT
Fasten a common carpenter's square in a slit to the top of a stake by
means of a screw, and then tie a plumb-line at the angle so that it
may hang along the short arm, when the plumb-line hangs vertically and
sights may be taken over it. A carpenter's spirit-level set on an
adjustable stand will do as well. The other arm will then be a level.
Another very simple, but effective, device for finding a level line is
by means of a triangle of wood made of half-inch boards from 9 to 12
ft. long. To make the legs level, set the triangle up on fairly level
ground, suspend a plummet from the top and mark on the cross-piece
where the line touches it. Then reverse the triangle, end for end,
exactly, and mark the new line the plumb-line makes. Now make a new
mark exactly half way between the two, and when the plumb-line
coincides with this, the two legs are standing on level ground. For
short water races this is a very handy method of laying out a level
line.
TO MEASURE THE HEIGHT OF A STANDING TREE
Take a stake about your own height, and walking from the butt of the
tree to what you judge to be the height of the timber portion you
want, drive your stake into the ground till the top is level with your
eyes; now lie straight out on your back, placing your feet against the
stake, and sight a point on the tree. AB equals BC. If BC is, say 40
ft., that will be the height of your "stick of timber." Thus, much
labour may be saved in felling trees the timber portion of which may
afterwards be found to be too short for your purpose.
LEVELLING BY ANEROID BAROMETER
This should be used more for ascertaining relatively large differences
in altitudes than for purposes where any great nicety is required. For
hills under 2000 ft., the following rule will give a very close
approximation, and is easily remembered, because 55 degrees, the
assumed temperature, agrees with 55 degrees, the significant figures
in the 55,000 factor, while the fractional correction contains /two
fours/.
Observe the altitudes and also the temperatures on the Fahrenheit
thermometer at top and bottom respectively, of the hill, and take the
mean between them. Let B represent the mean altitude and b the mean
temperature. Then 55000 X B - b/B + b = height of the hill in feet for
the temperature of 55 degrees. Add 1/440 of this result for every
degree the mean temperature exceeds 55 degrees; or subtract as much
for every degree below 55 degrees.
TO DETERMINE HEIGHTS OF OBJECTS
/By Shadows/
Set up vertically a stick of known length, and measure the length of
its shadow upon a horizontal or other plane; measure also the length
of the shadow thrown by the object whose height is required. Then it
will be:--As the length of the stick's shadow is to the length of the
stick itself, so is the length of the shadow of the object to the
object's height.
/By Reflection/
Place a vessel of water upon the ground and recede from it until you
see the top of the object reflected from the surface of the water.
Then it will be:--As your horizontal distance from the point of
reflection is to the height of your eye above the reflecting surface,
so is the horizontal distance of the foot of the object from the
vessel to its altitude above the said surface.
/Instrumentally/
Read the vertical angle, and multiply its natural tangent by the
distance between instrument and foot of object; the result is the
height.
When much accuracy is not required vertical angles can be measured by
means of a quadrant of simple construction. The arc AB is a quadrant,
graduated in degrees from B to A; C, the point from which the plummet
P is suspended, being the centre of the quadrant.
/When/ the sights AC are directed towards any object, S, the degrees
in the arc, BP, are the measure of the angle of elevation, SAD, of the
object.
TO FIND THE DEPTH OF A SHAFT
/Rule/:--Square the number of seconds a stone takes to reach the
bottom and multiply by 16.
Thus, if a stone takes 5 seconds to fall to the bottom of a shaft--
5 squared = 25; and 25 X 16 = 400 feet, the required depth of shaft.
DESCRIPTION OF PLAN FOR RE-USING WATER
Where water is scarce it may be necessary to use it repeatedly. In a
case of this kind in Egypt, the Arab miners have adopted an ingenious
method which may be adapted to almost any set of conditions. At a is a
sump or water-pit; b is an inclined plane on which the mineral is
washed and whence the water escapes into a tank c; d is a conduit for
taking the water back to a; e is a conduit or lever pump for raising
the water. A certain amount of filtration could easily be managed
during the passage from c to a.
COOLING COMPOUND FOR HEATED BEARINGS
Mercurial ointment mixed with black cylinder oil and applied every
quarter of an hour, or as often as expedient. The following is also
recommended as a good cooling compound for heavy bearings:--Tallow 2
lb., plumbage 6 oz., sugar of lead 4 oz. Melt the tallow with gentle
heat and add the other ingredients, stirring until cold.
CLEANING GREASY PLUMMER BLOCKS
When, through carelessness or unpreventable cause, plummer blocks and
other detachable portions of machinery become clogged with sticky
deposits of grease and impurities, a simple mode of cleansing the same
is to take about 1000 parts by weight of boiling water, to which add
about 10 or 15 parts of ordinary washing soda. Keep the water on the
boil and place therein the portions of the machine that are to be
cleaned; this treatment has the effect of quickly loosening all
grease, oil, and dirt, after which the metal is thoroughly washed and
dried. The action of the lye is to form with the grease a soap soluble
in water. To prevent lubricating oil hardening upon the parts of the
machinery when in use, add a third part of kerosene.
AN EXCELLENT ANTI-FRICTION COMPOUND
For use on cams and stamper shanks, which will be harmless should it
drop into the mortar or stamper boxes, is graphite (black-lead) and
soft soap. When the guides are wooden, the soft soap need not be
added; black-lead made into a paste with water will act admirably.
TO CLEAN BRASS
Oxalic acid 1 oz., rotten stone 6 oz., powdered gum arabic 1/2 oz.,
sweet oil 1 oz. Rub on with a piece of rag.
A SOLVENT FOR RUST
It is often very difficult, and sometimes impossible, to remove rust
from articles made of iron. Those which are very thickly coated are
most easily cleaned by being immersed in a nearly saturated solution
of chloride of tin. The length of time they remain in this bath is
determined by the thickness of the coating of rust. Generally from
twelve to twenty-four hours is long enough.
TO PROTECT IRON AND STEEL FROM RUST
The following method is but little known, although it deserves
preference over many others. Add 7 oz. of quicklime to 1 3/4 pints of
cold water. Let the mixture stand until the supernatant fluid is
entirely clear. Then pour this off, and mix with it enough olive oil
to form a thick cream, or rather to the consistency of melted and re-
congealed butter. Grease the articles of iron or steel with this
compound, and then wrap them up in paper, or if this cannot be done,
apply the mixture somewhat more thickly.
TO KEEP MACHINERY FROM RUSTING
Take 1 oz. of camphor, dissolve it in 1 lb. of melted lard; mix with
it (after removing the scum) as much fine black-lead as will give it
an iron colour; clean the machinery, and smear it with this mixture.
After twenty-four hours rub off and clean with soft, linen cloth. This
mixture will keep machinery clean for months under ordinary
circumstances.
FIRE-LUTE
An excellent fire-lute is made of eight parts sharp sand, two parts
good clay, and one part horse-dung; mix and temper like mortar.
ROPE-SPLICING
A short splice is made by unlaying the ends of two pieces of rope to a
sufficient length, then interlaying them, draw them close and push the
strands of one under the strands of the other several times. This
splice makes a thick lump on the rope and is only used for slings,
block-straps, cables, etc.
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