APPARATUS TO FACILITATE EXCAVATING, SINKING, AND MINING
Year: 1830

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME. I, SIR
THOMAS COCHRANE, Knight, (commonly called Lord Cochrane,) of Regent
Street, in the County of Middlesex, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twentieth day of October, One thousand eight hundred
and thirty, in the first year of His reign, did, for Himself, His heirs and
successors, give and grant unto me, the said Sir Thomas Cochrane, His
special licence, sole privilege and authority, that I, the said Sir Thomas
Cochrane, my exors, adiñiors, and assigns, or such others as I, the said Sir
Thomas Cochrane, my exors, adñiors, or assigns, should at any time agree
with (and no others), from time to time and at all times during the term of
years therein mentioned, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of "APPARATUS TO FACILITATE EXCAVATING, SINKING, AND MINING;" in
which said Letters Patent is contained a proviso that I, the said Sir Thomas
Cochrane, shall cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, to be inrolled in
His said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent, as in
and by the same, reference being thereunto had, will more fully and at large
appear.

page_text: NOW KNOW IE, that in compliance with the said proviso, 1, the said
Sir Thomas Cochrane, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, is particularly ascertained
and described in mauner following (that is to say) :-
MyInvention consists in an apparatus(herein-after described) for compress-
ing atmospheric air (into and rotaining the air so compressed) within the
interior capacity of subteranean excavations, sinkings, or mines,orwithin those
portions of that capacity where the operations of excavating, sinking, and
mining are going on, in order that the additional elasticity given to (and main-
tained in) the included air by aid of my apparatus (over and above the ordi-
nary and natural elasticity of the atmospheric air which is contained in
excavations and mines) may counteract (in part or wholly) the tendancy of
superincumbent water (or of such superincumbent earth as is rendered semi-
flued by admixture with water) to flow by gravitation into such excavations,
which (as aforesaid) are filled with compressed air, and maintained full of
compressed air by aid of my said apparatus, and which apparatus, at the samo
time that it is adapted to retain the said included air in astate of compression,
in order to prevent or diminish the influx of water or of semi-fluid carth, is
also adapted to allow workmen to carry on their ordinary operations of exca-
vating, sinking, and mining, by working underground within the space which
is filled with compressed air, and also to allow workmen ready passage to and
from the said space into the open air, or to and from the said space into those
parts of the subtereancan excavations or mines which contain air in a natural
and ordinary state of elasticity. And other parts of my said apparatus faci-
litates the passage of materials to and from the open air into and out of those
parts of the subterranean excavations or mines which are filled as aforesaid
with and retained full of condensed air, by aid of my apparatus, or the
said parts facilitate the passage of materials into and out of those parts of the
subterranean excavations which contain compressed air, to and from other
parts of such excavations which contain air in its natural and ordinary elas-
ticity. The construction of my said apparatus must be greatly varied accord-
ing to the circumstances of the situation in which it is to be applied. The
essential properties of my Invention will be explained by the following descrip-
tion of an apparatus, which is made according to my Invention, for the purpose
of sinking a perpendicular shaft at the shore by the side of a river, and then
excavating a drift or tunnel from the bottom of that shaft to extend horizon-
tally (or nearly so) beneath the bed of that river, being a similar undertaking
to that which is now executing beneath the river Thames at Rotherhithe
A, B, Figure 1, represents a column of cast iron cylinders joined together one

page_text: above the other by internal flanges, which are united by screw bolts so as to
make air-tight joints by the aid of packing or cement interposed between the
flanges, the column being smooth on the outside of the cylinders. This column
being raised to a sufficient height to give it weight, will descend as fast as the
earth or soil within it is excavated. Suppose this shaft to be thus sunk in the
earth until it reaches a bed, d, c, of loose soil, which admits water so copiously
that the surface of that water cannot be kept down to the bottom of the shaft
by ordinary means; in such case I fix an air-tight cover over the top of the
uppermost of the iron cylinders, to close its apperture, and I apply a condensing
air pump, worked by steam power or other power, to force air into the interior
capacity of the shaft or column of iron cylinders until so much additional air
is condensed therein beyond that quantity which the interior capacity of the
said sbaft would naturally contain as that the said included air will exert a
strong force of pressure to repel and keep out the water from entering into
any part of the interior capacity thereof. The workmen who are employed
to excavate, sink, or mine the earth at the bottom of such shaft must work
within the compressed air; but to give them ready entrance to and exit from
the open air into the compressed air, I apply an anti-chamber to the air-tight
cover over the top of the uppermost iron cylinder, that anti-chamber having
two doors, an outer door and an inner door, both opening inwards towards the
space which is filled with compressed air. When the outermost door of the
anti-chamber is open the innermost door will retain the compressed air within
the shaft. The opening of that outer door gives free entrance into the anti-
chamber, and the workman can enter therein with his tools, and with such
other articles as he may require to take into the shaft with him; then, shutting
the outermost door after him, he pushes open a hanging or flap valve in the
inner door, to allow a quantity of condensed air to enter into and fill the anti-
chamber until the air therein acquires an equality of elastic pressure with the
condensed air contained in the shaft, and that quality of pressure acting on
both sides of the inner door, the workman can push open that inner door and
descend from the anti-chamber into the shaft, carrying with him the tools and
other articles which he had previously deposited in the anti-chamber. And in
like manner, to enable a workman to go out from the shaft into the open air,
he can readily open the inner door which communicates with the shaft into the
anti-chamber, provided that he has previously pushed open the small flap
valve in the inner door, and thereby admitted the condensed air to enter from
the shaft into the anti-chamber until that air comes to an equality of elastic
pressure on both sides of the inner door; the workmen can then enter from
the shaft into the anti-chamber, and after closing that inner door after him

page_text: he pulls open the small flap valve in the outer door, to allow the compressed
air to escape from the anti-chambers into the open air until an equality of
elastic pressure is established on both sides of the outer door, which may then
be opened to allow the workman to walk out from the anti-chamber into the
open air, carrying with him his tools or other articles which he may have depo-
sited in the anti-chamber. The said anti-chamber may be a small apartment
made of wrought iron plates rivetted together like a tank or a boiler, in form
of a centry box, and it may be made only large enough to admit one workman
at a time into it. The doors will shut close of themselves by the pressure of
the air against them, and the joints may be made tight by leather borders in-
terposed in the fitting parts. The small hanging flap valves in the large doors
will be only of such size as can be readily pushed or pulled open against the
pressure of the air, and they will keep shut of themselves when left at liberty.
With this apparatus the excavating, sinking, and mining of the earth from the
bottom of the said shaft will be facilitated, because the water will be kept out
therefrom; or if the depth of the hydrostatic column by which the water is
urged to enter into the shafts is considerable, it may not be adviseable in all
cases to condense the air so much into the shaft as to wholly counteract the
tendency of the water to enter into the bottom of the shaft, but only to dimi-
nish that tendency so much that the water which does come in may be easily
extracted; and in order to extract that water without allowing any of the com-
pressed air to escape from the shaft, a pump may be put down through an
aperture in the cover of the shaft (being closely jointed to that aperture), so as
to prevent the escape of any air around the pump. This pump may be
worked by steam or other power, but it will be worked with case because the
elastic pressure of the condensed air with which the shaft is filled bearing
upon the surface of the water which stands in the sump at the bottom of
the shaft (and in which water the lower end of the pump is immersed),
will force a column of water up into the pump, and that column will not
weigh on the bucket of the pump when it is drawn up in the barrel by steam
power or other power, because the atmospheric air presses on the surface
of the water which is delivered by the pump at the top of the barrel with
much less elastic force than the compressed air prosses on the surface of
the water at the stump; and in order to draw up or extract mud or earth
from the shaft without allowing any compressed air to escape from the
shaft, an endless chain of buckets may be applied, like those used for the
dredging machines which are commonly employed to deepen the beds of
rivers. The uppermost roller of the two rollers over which that endless chain
circulates being turned forcibly round by steam power or other power, the.

page_text: two sides of the clain of buckets must work up and down within two vertical
or including tubes, which are so closely joined at their upper ends 'to two
apertures in the cover of the shaft as not to admit any air to escape by
the tubes. The lower ends of those tubes are open, and are immersed
beneath the surface of the water which is contained in a sump or cistern
at the bottom of the shaft. The elastic pressure of the condensed air contained
within the shaft acting upon the surface of that water will force a column
of water to rise up and stand up within the two tubes, and the mud or
earth, being thrown into the bottom of the said sump or cistern, will be
dredged up therefrom by the buckets, and carried up through the said columus
of water, and will thence be raised up above the close cover of the shaft,
in order to be discharged at top; and in order to introduce bricks, stones,
or such other articles into the shaft without allowing the escape of any
compressed air from the shaft, they may be thrown down through a large
pipe or tube, which is closely fitted into an aperture through the cover of
the shaft so as to allow no air to escape around it, and the lower end of
the said tube being open, and immersed in water contained in a cestern or
sump at the bottom of the shaft, the bricks and stones which are thrown
down through the said tube will go to the bottom of such cistern, and may
be taken out therefrom under water. A column of water will will, as in
the former cases, be kept standing up in the said tube by the elastic pressure
of the condensed air on the surface of the water in the said cistern or sump,
and the bricks or stones will descend through that column of water in falling
to the bottom of the tube. And when, by aid of my aforesaid apparatus, the
earth and soil at the bottom of the shaft is sufficiently excavated to permit
the iron column of cylinders to be sunk deeper down into the earth, in case
that column should not prove heavy enough to sink by its own weight whilst
it remains filled with compressed air, the workman may come out from the
shaft, and then let out the compressed air from it, in order that the iron
column may have no impediment to its sinking down into the excavated earth
from the elastic pressure of the compressed air acting upwards beneath the
close cover over the top of the iron column. Note, if the column of iron
cylinder is rendered sufficiently heavy it will sink of itself (without thus
letting out the compressed air) as fast as the earth is excavated from under it
at the bottom of the shaft; and in order to load the said column of iron cylin-
ders with a sufficient weight, the condensing air-pump and also the steam-
engine by which it (together with the water pump and the endless chain of
buckets before described) is to be worked, may be placed upon a platform,
which is laid over the cover or close top of the uppermost of the iron

page_text: '
cylinders. When the iron column is by these means got down as low
as it is required to descend into the earth, the horizontal drift or tunnel
may be begun, by setting out from one side of the bottom of the vertical
shaft. If the influx of water from the earth at the bottom of the shuft
continues to be considerable, that bottom may be covered over with
an inverted arched dome of brick work which is impenetrable to water,
because, altho' by the aid of my apparatus for retaining compressed nir
in the shaft the influx of water may be greatly restrained and diminished,
still it will be adviseable to leave no greater surface of earth exposed to yield
water than is necessary to be opened at once for the purpose of progressing
with the excavation, and therefore when a new surface of earth is opened at
the end of the horizontal tunnel it will be adviseable to cover over and shut
up the surface of earth at the bottom of the shaft. As the tunnel is driven
horizontally, my apparatus will continue to repel the water and semifluid
earth from entering the excavation wherein the compressed air is retained by
it. When the working has been carried some distance along the tunnel,it may
be advisable to fix an air partition across the aperture of the tunnel,and apply
another condensing air pump thereto, (or attach to that partition an air pipe,
which extends from the condensing pump at the surface), in order to fill the
space beyond that partition with air in a greater degree of condensation than
that condensed air wherewith the vertical shaft is filled. By this means the
workmen who remain in the vertical shaft will not be required to work in
air which is so strongly compressed as the air in which those workinen who
are making the excavation at the end of the tunnel must work. The said
partition must be provided with an anti-chamber, containing two doors of the
same kind as before described, to enable the workmen to go through the
partition, and to take with them all tools and materials which they require for
carrying on the excavation and building of the tunnel at the farther end
beyond the partition, and also to bring out the earth which they excavate.
The said anti-chamber must have a flange joint around that end of it which
is beyond its inner doorway, for the facility of fixing it to the partition by screw
bolts disposed around the entrance aperture through the partition. And
whereas it will be inconvenient for the workmen to be shut up in very densely
compressed air, the number of persons required to be so shut up may be
diminished by making another intermediate partition at the entrance from the
iron cylinders (which constitute the vertical shaft) into the commencement of
the horizontal tunnel, that partition being provided with an anti-chamber
containing two doors, as before described. By these means the interior
capacity of the shaft and tunnel may in the whole be divided into three or

page_text: more distinct compartments, each of which is filled with air in a progressive
stageof compression, fromthe natural atmospheric elasticity to such elasticity
as will repel water from entering into the excavation. The pressure of the
air against each partition, and against the doors of its anti-chamber, will be
rendered small by this subdivision of the total compression. The first or
outermost compartment will be the vertical shaft, in which the air need not
be compressed more than two thirds of an atmosphere beyond the external
air. The next compartment will be the entrance portion of the horizontal
tunnel, and the air therein may be compressed two thirds of an atmosphere
beyond the compression of the air contained in the first compartment, or one
and one third atmospheres beyond the external air. The principal number of
the workmen necessary for the underground operations may be included
within the second compartment. The third compartment will be the further
end of the tunnel, where the excavation and tunnelling is actually going on
beyond the interior partition. The air therein may be compressed two thirdsof
anatmosphere beyond the elasticity of the air in the second compartment, and
then it will be two atmospheres beyond the elasticity of the external air.
That degree of compression will balance a column of water of sixty-seven feet
perpendicular height, so that if the surface of the water in the river is not
more than that height above the excavation of the tunnel, the compressed air
which is retained therein by my apparatus will effectually prevent any influx
of water from the river into the excavation; but it will not be necessary at all
times to keep up such a great compression of air in the excavation; only
at times when the ground which is in progress of excavation is so loose
that there is danger of an irruption of water from the river.
When the
ground is very firm and safe, the degree of condensation of the included
air may be greatly diminished, or it may be relinquished altogether, keeping
all my apparatus in order for the purpose of renewing the compression
atany time when the nature of the ground which is in thecourse of excavation
may render it necessary to repel the influx of water or of mud or of the
loose earth, by a counter pressure of the included air. When the horizontal
tunnel is far advanced beneath the bed of the river,a direct vertical communi-
cation may be opened with the furthermost compartment of the tunnel, by
boring a vertical hole, and putting down therein a column of iron pipes, h, z,
which must be of sufficient size to admit a small bucket to work up and down
within them. The said pipes may be fixed in the bottom of the river by the
same means that pipes are commonly put down into the earth as substitutes
for wells, and the pipes must extend from above the surface of the water inthe
river down into a chamber Z, made by the side of the tunnel, for the reception

page_text: of the lower end of the vertical pipe, and communicating laterally with the
interior of the tunnel. The lower part of the chamber must form a large
cistern, to receive the drainage water of the excavation, and in that water the
lower end of the vertical pipe must be immersed, to prevent the compressedair
from escaping up the pipe; but the pressure of that air upon the surface of
the said water will raise a coluinn of water within the pipe, and maintain that
column therein at a height suitable to the degree of compression of the air
which is retained within the excavation by my apparatus. The earth which is
excavated from the end of the tunuel may be drawn up in a bucket through
the vertical pipo h,,by filling that bucket, and introducing it under the water
in the cistern beneath the open end of the pipe which is immersed in that
water. The bucket must go up through the column of water which is kept
standing in the pipe. In like manner bricks or stones may be thrown down
through the said vertical pipe through the water which stands therein, and
they will descend to the bottom of the cistern, from whence they may be taken
out under water, as before described.
In witness whereof, I, the said Sir Thomas Cochrane, commonly called
Lord Cochrane, have hereunto set my hand and seal, this Twentieth
day of April, in the year of our Lord One thousand eight hundred and
DOWDESWEITU.
AND BE IT REMEMBERED, that on the Twentieth day of April, in the
year of our Lord 1831, the aforesaid Sir Thomas Cochrane, Knight, (com-
monly called Lord Cochrane,) came before our said Lord the King in His
Chancery, and acknowledged the Specification aforesaid, and all and every
thing therein contained and specified, in form above written. And also the
Specification aforesaid was stamped according to thete norof the Statute made
Inrolled the Twentieth day of April, in the year of our Lord One
thousand eight hundred and thirty-one.