The production of the baser metals, here and abroad, increased
gradually with the demands of the mechanic arts, but it was not until
the middle of the century that this factor, joined with the improved
methods of transportation, and of metallurgy, gave to mining that
impetus which, though through alternate recurring waves of prosperity
and stagnation, carried it forward until the annual expenditure for
technical skill, machinery, and supplies used in the industry is
estimated to-day at one thousand million dollars.
The first mining excitement in the United States occurred in 1829,
following the discovery of gold in the South; but these fields soon
declined in importance without resulting in any improvements to mining
methods and machinery.
The next mining fever resulted from the inauguration of work upon the
copper properties at Keweenaw Point, Mich., in 1845. This caused the
first mining-stock speculation in this country, and it is interesting
to note that the century closes with a repetition of this same fever,
founded upon almost the same ground. Yet the conditions have changed
wonderfully. Upon the then barren peninsula, whitened with the tents
of speculators and geologists, has grown up a multitude of towns,
filled with thousands of people whose labors are performed at a depth
of nearly a mile under ground. Thousands more transport the ore to the
mills, separate the copper from the rock, and cut timber for the mines;
while yet other thousands prepare food and clothing and shelter for
all these. During 1898, the copper mines about Lake Superior produced
nearly 160,000,000 pounds of copper, and paid in dividends $6,490,000.
[Illustration: THE SERGEANT ROCK DRILL.]
This district is the only one in the United States where the man-engine
has been used; but as the shafts were sunk deeper and deeper, it was
found that even this method was not sufficiently rapid, and the men are
now lowered into the mines by cages or skips. A “cage” is simply the
miners’ name for the ordinary elevator when used underground, and has
developed from the bucket in use at the beginning of the century. A
“skip” is a car especially designed for use on an incline. The roadway
upon which the skip runs is so planned, at the top of the shaft, that
the rear wheels run upon a track raised above the one over which the
front wheels pass, so that the rear end is elevated and the skip is
dumped automatically. At the De Beers diamond mines in South Africa
are two of these skips which hold nearly five tons of rock each. At
the bottom of the shaft are chutes containing the rock, and when the
skip is in position a man pulls a lever, allowing the ore to run into
it. Another pull closes the chute, a button is touched which rings a
bell in the engine-room, and the skip starts up the shaft. At the top
it dumps itself and returns to be filled again. In the mean time the
other skip has been filled and is going up while the first is coming
down. With these two skips, making ninety-two trips an hour, over four
thousand tons of rock have been hoisted in less than twelve hours, from
a depth of 1250 feet.
To handle these enormous quantities tremendous hoisting engines are
used. At the Calumet and Hecla mines is a pair of quadruple expansion
engines which will lift cages, carrying six tons of ore, a mile in a
minute and a half. The “Modoc” hoist, built for the Anaconda Mining
Company of Butte, Montana, is the largest hoist in the world. It is
a double compound beam engine, and is designed to be used in sinking
to a depth of 6000 feet. This machine weighs four hundred tons, and
has seven separate subordinate engines for use in operating it. Think
of it! An engine so ponderous that smaller engines are necessary to
apply the clutches that set the reels in motion; other engines set
the brakes, and another reverses the action, if need be. All these
are controlled by levers operated from the engineer’s platform, the
“runner” having one foot and seven hand levers to handle. Besides these
there are two indicator discs, directly in front, requiring constant
attention, for these show the exact position of the cage in the shaft.
Yet such wonderful skill have the runners in the control of these
veritable flying machines that they instantly interpret the complicated
signals, and drop the cage with such exactness that the car of ore
is run from the track in the level to the track on the cage, almost
without a jar.
[Illustration: INGERSOLL-SERGEANT STEAM-DRIVEN AIR COMPRESSOR.]
Nor is the hoist the only large machine necessary in the equipment of
the modern mining plant, for in sinking to great depths vast quantities
of water have to be removed. The Chapin Mining Company, at Iron
Mountain, Mich., have one of the largest pumping engines in the world.
This engine is located on the surface, driving the pumps after the
Cornish style, though it would be difficult to see much of the pump of
1801 in this magnificent machine. With a ten-foot stroke it conveys the
power to the pumps through a walking beam weighing a hundred tons. In
an hour it will raise nearly 200,000 gallons of water from a depth of a
quarter of a mile.
[Illustration: DRIVING A RAILWAY TUNNEL WITH THE INGERSOLL “ECLIPSE”
ROCK DRILL.]
Imagine the miner of 1800 “softening by fire” sufficient ore to supply
a modern hoist. For the mines which now turn out 2000 tons a day can by
no means be counted on one’s fingers, and 2000 tons means more than a
foot deep over a whole city block. Before the middle of the century the
use of powder and drill had largely increased, and in 1845 an attempt
was made to aid the man behind the drill with a machine which swung a
hammer by steam power. In 1805 a machine was invented using compressed
air in a cylinder, and this was gradually improved until it became a
success in 1861, in the Mont Cenis tunnel. As finally employed, the
power drill is practically a small engine, the drill being attached to
the piston rod and moved rapidly back and forth by compressed air or
steam. The machine has three functions: to strike the blow, turn the
drill, and advance it, as the hole is driven deeper and deeper.
[Illustration: INGERSOLL-SERGEANT STRAIGHT LINE AIR COMPRESSOR.]
Soon after the machine drill became a success dynamite was invented,
and these two have been the greatest factors in bringing about that
rapid development and production which is the most pronounced attribute
of modern mining. Dynamite alone has doubled the amount of ore which
can be extracted from a face in a given time. Le Neve Foster, in his
work on mining, gives the rate of advance in driving a tunnel by fire
setting at two fathoms per month. Compare with this the Niagara Falls
tunnel, driven with power drills and high explosives, 342 feet in four
weeks.
It is probably to the power drill more than to anything else that we
are indebted for the development of the air compressor; the exhaust
from a steam drill and the heat emitted from the pipes being very
disagreeable under ground. As early as 1800 a Welsh engineer had
attempted to run a blast by means of a water power a mile and a half
distant, but it was not until 1865 that machines were operated to
any extent by compressed air. The great difficulty had been the loss
of efficiency, owing to the clearance spaces and the heating of the
air. In driving the Mont Cenis tunnel but 16 per cent of the power
developed was available, and up to 1880 the efficiency was extremely
low; but to-day as high as 80 per cent is obtained. The air compressor
is simply a force pump with ingenious devices to overcome the loss of
energy. For ordinary use the air is compressed to a pressure of from
60 to 80 pounds per square inch. This is done in a single cylinder for
low pressures, but for high pressures two cylinders are used. From the
compressor the air is conducted to a reservoir, from which it is piped
to the machine which it is to run.
[Illustration: INGERSOLL-SERGEANT DUPLEX STEAM-DRIVEN AIR COMPRESSOR.]
One of the advantages of air-driven machines under ground is that the
exhaust furnishes fresh air to the miners and cools the atmosphere. The
result has been that in metal mines, where there are no noxious gases
escaping from the ground, the exhaust from the air-drills, together
with the natural air currents, has supplied sufficient ventilation.
In the coal mines, however, it has been necessary to employ other
means. After it was found that, even with the safety-lamp, gas would
be exploded if a large amount of it had accumulated, more attention
was paid to ventilation. Levels and shafts were divided to produce
a natural current; the size of the drifts was carefully figured in
order to regulate it; doors were put in to compel it to follow the
faces; devices were adopted to split it, a part going to one room, the
remainder to a second; and boxes were built to carry one current across
another. Early in the century hand fans run by a wheel and pinion had
been employed for forcing the air down the shaft, but it was soon found
that the circulation produced in this way was inferior to the result
of eduction. Large furnaces were then constructed at the bottom of the
upcast shafts, in order to cause a strong upward current. Again, huge
air pumps, run by machinery, were tried for exhausting the air. By 1850
exhaust fans were coming into use, and these, occasionally replaced
by blowers, also used for exhausting, are now generally employed. The
Guibal, which has been the most prominent of the fans, has been made as
large as forty-six feet in diameter. The Capell, which is an improved
form of the Guibal, has six curved veins, or blades, and is made from
eight feet to fifteen feet in diameter. It is driven quite rapidly,
making from one hundred and eighty to three hundred revolutions,
and having a capacity of from one hundred thousand to three hundred
thousand cubic feet of air, per minute. The result of this thorough
ventilation is that the gas is removed from the mine almost as rapidly
as it enters, and often the safety-lamp is no longer needed by the
common miner. Nevertheless, it has by no means become useless, since
as an indicator of the presence of gas it is invaluable. The action of
the different lamps in the presence of gas varies, but in general the
size of the flame increases in direct proportion to the increase in the
amount of gas mixed with the air. Each morning, before the men go to
work, the fire boss takes his safety-lamp and makes the round of the
mine. When he goes into a room he watches the flame, and if it burns up
to the point which indicates that it would not be safe to enter with a
naked light, he makes a mark on the wall which serves as a danger line
beyond which the men do not go.
Another machine, which, like the fan, has been developed by the demands
of the coal mines, is the coal-cutting machine. Probably the lot of
no man was as hard as that of the coal-digger at the beginning of
the century. After he had performed the dangerous task of exploding
the accumulated gases, he was often forced to work all day lying in
the most constrained attitude. Applied in this manner, his power was
largely wasted, and much useless dust and small coal was produced. The
first effort at relief was a machine which imitated the miner, striking
a blow with a pick worked by a lever, and making as high as seventy
blows a minute. These have been generally replaced by quite another
type of machine, one which depends on the action of either a rotary
bar, a rotary wheel, or a chain cutter. These machines are operated by
either air or electricity. The Jeffrey rotary bar cutter will undercut
a block of coal thirty-nine inches by fifty-four inches in six minutes.
The chain-cutter is an endless chain carrying cutting knives and
traveling horizontally. It is claimed that these machines will effect a
saving of about ten cents a ton in the cost of mining.
When in 1848 the finding of gold in California was reported, followed
in 1851 by the discovery of the Australian fields, large numbers of men
were attracted to the placer mines, who later, as the placers became
exhausted, turned their attention to vein mining. Nor did hydraulic
mining itself fail to progress. When the placers were first discovered,
the miner, standing in the shallow stream, washed the gravel, a panful
at a time, and secured from fifteen to twenty-five dollars a day. As
the placers became poorer he built sluices, and, shoveling in his
gravel, turned the stream in to wash off the light rock, while the
heavy gold was caught in the interstices between the blocks with which
he had paved the bottom. If the ground became clayey, he brought part
of the water through a hose and used it to break up the lumps in his
sluice box. Then as he gradually removed the gravel and the banks about
him became higher, he turned his hose toward the bank and brought
more water from a higher level, until, to quote Bowie, “a forty-inch
wrought-iron pipe has been substituted for canvas hose and a stovepipe,
and an inch stream replaced by a river of water discharged through a
nine-inch nozzle under a four-hundred-foot pressure.” By this means, at
North Bloomfield, Cal., nearly a million yards of gravel, containing
but two and nine tenths cents per cubic yard, was moved in a single
season, and at a profit.
[Illustration: ELECTRIC COAL-MINING MACHINE.]
As the banks became poorer, the miners turned their attention to the
river beds. In New Zealand, in the early days, they worked the banks as
far down into the river as they could reach with a spoon dredge. Then a
dredge was made resembling a ladder of buckets, continually revolving,
and operated by wheels driven by the current. When the river got low
the current became too weak, and a steam engine was substituted. Then a
revolving screen was put on to separate the large rocks from the fine
sand, and gradually the modern dipper dredge has been evolved, with
its pumps, screen, distributors, and tables and sluices, handling 2000
yards of gravel a day at a cost of three cents a yard.
In 1859 the Comstock lode in Nevada was discovered, and it is to this
district that we owe the “square set” method of timbering, so largely
in vogue in wide veins to-day. Some of the “bonanzas,” that is, pockets
of rich ore, were of enormous size. For example, one found in the
“Gould and Curry” was 400 feet long, 80 feet wide, and 400 feet deep.
As the walls were not sufficiently solid to stand unsupported, and a
single stick of timber was too short to reach across, splicing was
tried. It was soon found that this weakened the timber too much, and
the method of square “setting” was invented. This consists in framing
timbers together in rectangular sets, having a square base of four
pieces, usually six feet long, placed horizontally as sills. Into these
are framed posts, surmounted by a cap of four additional timbers which
become the base for the next set. The timbers are usually twelve inches
square, and cost on the Comstock about $10 a set. From 1870 to 1891
there is said to have been used up on the Comstock 200,000 acres of
forest, valued at $45,000,000.
The amount of timber which is consumed under ground in a single year
must be enormous. Mr. C. W. Goodale estimates that in Butte alone, in
1895, 37,500,000 feet, equal to 3750 carloads, were used in the mines.
As the timber decays in from five to fifteen years, and has to be
replaced, efforts are constantly directed toward decreasing the large
expense which is thus continually recurring. In shafts and levels for
permanent use iron is an economical substitute. Wherever possible, new
methods of mining are being introduced. Thus in the Lake Superior iron
regions, the mine development is planned along lines almost unheard of
ten years ago. In the first place the gravel which overlies the ore is
stripped off, even if it is fifty feet thick. This is done with steam
shovels, which load the gravel upon cars. These are then pulled away by
one locomotive while a second places new “empties” in position to be
filled. One shovel will load from 150 to 175 cars a day; that is, will
take from 3500 to 4500 tons of dirt from the sides of the pit and put
it upon the cars. This method obviates the use of timber for holding up
the surface.
After the overlying gravel is removed, should the conditions be
favorable, the ore is taken out with a shovel. If this cannot be done,
some method depending on rock-filling is adopted. At the Auburn mine,
after stripping and driving the levels, raises are made to the surface
at intervals of about fifty feet, the ore broken down around them,
starting at the surface, and dropped down through them. This leaves
openings in the shape of inverted cones, having their bases at the
surface. Additional raises are then made halfway between the others,
and the remaining material extracted.
[Illustration: GOLD DREDGING ON SWAN RIVER, COLORADO.]
At the Fayal mine they take out rooms twenty-four feet wide by three
hundred feet long, with a twenty-four-foot pillar between them. These
rooms are carried up from the first level to the surface, and filled
with gravel which is run in from above. Then the pillars are mined by
“slicing and caving;” that is, by running drifts along the sides of
the pillar and caving the ore down from the roof. After removing this
ore another drift is run, the roof caved, and another slice taken off.
It is claimed the saving in timber by using this method amounts to ten
cents on each ton of ore mined.
All of these, and many other inventions, have constantly tended to
decrease mining costs. Yet the industry is carried on to-day in so
many out-of-the-way places, and under such varying conditions, that
the cost per ton of the ore mined vacillates between wide extremes. As
an example of what can be accomplished, working on a large scale, and
where supplies are easily and quickly obtained, the Atlantic mine, in
Michigan, may be mentioned. This mine produced, in 1898, 370,000 tons
of ore, at a cost of sixty-six cents per ton.
With all these wonderful advances in mine mechanics, engineering,
ventilation, and lighting, have come the foundation and development
of mining schools, the rise of technical societies, and a general
governmental recognition of the importance of the industry. It is
not so very far back in the preceding century that we find among the
statutes of England the following: “Stealing ore out of mines is no
larceny, except only those of black lead, the stealing ore out of
which is felony without benefit of clergy.” It would be interesting to
know the name of the gentleman who owned the black-lead mine, for, in
modern parlance, he certainly “had a pull.” By 1833 mining legislation
had so far progressed in England that laws were enacted regulating
the employment of children under ground. In this country, in 1830, a
state geological survey was inaugurated by Massachusetts, and this
institution has since been copied by many States. The majority of the
States where mining is carried on have passed laws tending to increase
the safety of men working under ground.
Abroad, carefully prepared codes describe the method of lease or sale
of mining rights, and define the rights of owners of ground. In this
country the first legislation of this character was in 1807, when the
government mineral bearing lands were withdrawn from sale and ordered
leased. In 1834 the miners refused to pay the royalty, owing to the
large number of illegal entries, and in 1847 the lands were opened to
sale. It was not until 1866, after fifteen years of self-government
among the miners of the West, that Congress earnestly undertook to
regulate the acquisition of mining titles on the public domain. Leagues
beyond the towns, miles from the nearest roads, hurrying from the
scene of one excitement to another, pushed by the crowd of constantly
arriving adventurers, with surveyors unobtainable and courts not
accessible, almost without time to measure, and in a region absolutely
unlocatable, it had been impossible for the miner of the West to
secure a legal title to his land as contemplated by the act of 1847.
Accordingly, there had grown up the custom which gave to the discoverer
of a lode the right to a certain length of it, and it was this right
which was recognized by Congress, and became the basis of the law of
1866.
So far our story has been of progress, but what shall we say of the
action of Congress, which, in 1872, abrogated this law and substituted
for it the prolific breeder of litigation called the law of the apex?
To quote Dr. Raymond: “The leading characteristic differs from all
previous mining laws of this or any other country. The old right of
discovery, which was the basis of the miner’s title down to 1872, has
dwindled under the present law to a nominal importance. It is true that
the discovery of the lode within the claim is made a prerequisite to
location. But the right to follow the lode in depth beyond the side
lines of the claim depends no longer upon having discovered it, but
on having included its top, or apex, in the surface survey.” Should
the miner be so fortunate as to have a vein which outcrops plainly on
the surface, he may stake out the ground without difficulty, so that
the vein crosses the end lines. But if his vein does not appear on the
surface, and he fails to guess its direction correctly, and finds, on
developing, that it does not cross the end lines of his claim, he is
suddenly cut off from all extra-lateral rights. Or should he, in laying
out his lines along the rough, precipitous mountain-side, fail to make
his end lines parallel, he again finds his rights limited. Nor has
this law been made clearer by court decisions, but rather it has been
complicated.
[Illustration: THE POWER PLANT AT JEROME PARK, N. Y.
(Ingersoll-Sergeant Duplex Corliss Condensing Air Compressor.)]
Certainly this is a peculiar condition of affairs. The century which
has witnessed an advance from the hazel rod to the diamond drill,
from the spade to the steam shovel, from fire softening to dynamite
shattering; a century during which a clumsy car pushed over cast-iron
rails by a boy has grown to a cable train, and a two-hundred-pound
bucket raised by women has developed into a six-ton self-dumping skip
hoisted by electricity; a century productive of new devices which
tunnel mountains, cross ravines, or sink through quicksands with equal
ease; a century which has seen the touch of a button and the turn of a
wheel bring power from thirty miles away to light and drain the mine,
as well as operate the drills and hoist; such a century closes with a
law in force in the greatest mining country in the world which makes
litigation one of the expected stages of mine development.
At the beginning of the century the mining engineer advised where to
sink, the manner of working, and the method of dealing with the water:
to-day he must not only be a mining, civil, and hydraulic expert, but a
mechanical and electrical engineer, a chemist, and a lawyer.