IMPROVEMENTS IN METHODS OF EMPLOYING EXPLOSIVE SUBSTANCES FOR BLASTING ROCK, IN ⚫ DRIVING TUNNELS OR LEVELS, SINKING SHAFTS, AND OTHER OPERATIONS OF THE LIKE KIND
Year: 1881

page_text: LETTERS PATENT to Edmund Edwards, of the Firm of Edwards and Co.,
Patent Agents and Engineers, of 40, Southampton Buildings, Chancery Lane,
in the County of Middlesex, for an Invention of "IMPROVEMENTS IN
METHODS OF EMPLOYING EXPLOSIVE SUBSTANCES FOR BLASTING ROCK, IN
⚫ DRIVING TUNNELS OR LEVELS, SINKING SHAFTS, AND OTHER OPERATIONS
OF THE LIKE KIND." A communication from abroad by Emile Wickersheimer
and Leopold Pech, both of Carcassonne, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at the
Office of the Commissioners of Patents on the 24th November 1881.
EDMUND EDWARDS, of the Firm of Edwards and Co., Patent Agents and
Engineers, of 40, Southampton Buildings, Chancery Lane, in the County of
Middlesex. "IMPROVEMENTS IN METHODS OF EMPLOYING EXPLOSIVE SUBSTANCES
FOR BLASTING ROCK, IN DRIVING TUNNELS OR LEVELS, SINKING SHAFTS, AND
OTHER OPERATIONS OF THE LIKE KIND." [A communication from abroad by
Emile Wickersheimer and Leopold Pech, both of Carcassonne, in the Republic
of France.]
This Invention has for its objects novel methods of preparing holes or chambers
in hard rock which it is desired to blast for the purpose of driving tunnels or levels,
or sinking pits, and of employing gunpowder, dynamite, or other explosive
materials in the holes or chambers so prepared.
In preparing such holes or chambers it is found to be advantageous that the
bottom or end of the hole which contains the explosive material should be chambered
or of larger size than the remainder of the hole, and for this purpose expanding or
other tools specially adapted have sometimes heretofore been used.
By the present Invention such chambered or enlarged holes can be prepared and
utilized by means of the drills or tools ordinarily used in mining, and great economy
is effected both in the time and cost necessary for making the holes, and in the
quantity of the explosive material used, a larger quantity of the rock being
removed by the process of blasting.
The accompanying Drawing is in illustration of the Invention. Figure 1 is a
section of the rock in the interior of which a chamber is to be formed to receive
the explosive material; a and b are two holes of small diameter drilled in the rock
by the ordinary well known means, near and parallel to each other. When drilled
[Pine Gd1

page_text: to a sufficient depth, one of the holes a is charged with gunpowder or other explosive,
and lightly tamped and rammed, the hole b remaining empty. The charge in a is
then fired in the usual way, and the tamping is expelled, and at the same time the
lower part of the wall or division between the two holes is broken, as shewn in
Figure 2.
The broken and powdered débris is partly blown out by the gas, and partly
collected at the bottom of the hole b as shewn, whilst the upper part of the holes
will remain unfissured.
The proportion between the size and depth of the holes, their distance apart, and
the quantity of explosive material may be varied to suit the character of the rock
and other varying conditions, and in some cases the empty space or chamber left
as shewn between the holes will be sufficient to receive a charge of blasting
material..
If necessary, the capacity of the chamber can be increased by removing the
débris remaining between the holes, as shewn in Figure 2, and for this purpose a
drawing and forcing pump is used by which water can be forced through a delivery
pipe fitted into a, whilst it sucks or draws by another fitted into b, a suitable
reservoir or receptacle being provided in the latter pipe in which the débris settles
and collects as it is withdrawn with the current of water. The valves and passages
of the pump may be arranged in the ordinary well understood way, so that if
desired in the case of any stoppage, the direction of the current may be reversed,
the water being forced into the hole b, and withdrawn through the hole a. The pipes
as described are preferably made of copper, as thin as possible, and they may be
made in separate lengths, fitted together, and connected by bayonet joints or other
convenient means,
Or instead of the pump, for the purpose of removing the débris in the way
described, the breaking of the dividing wall and the expulsion of the débris may
be effected at one operation, by placing one or more cartridges at the bottom of
the hole b. The explosion in the holo a as first described will break down the
dividing wall and will fire the charge in b, by which the débris will be then
expelled.
In this way a chamber is easily and readily obtained at a sufficient depth in the
body of the rock which is to be blasted. If a larger chamber is required, a third
hole may be drilled, as indicated at c in Figure 3, an opening from the bottom of
which may be made into the chamber already formed between a and b, the débris
being removed by the pump as already described, and similarly a fourth or any
number of holes may be added, the chamber being thus enlarged by the successive
explosions, and the danger of fissuring the rock, which would be probable if the
charges in all the holes were fired simultaneously, being avoided.
It is found advisable however that all the holes which are to be used should be
drilled before communication is made in the way described between the first two,
and in order to preserve the holes which are to be afterwards used, as for instance
the hole c in Figure 3, they are stopped or rammed to a sufficient height, the
stopping being removed after the explosion, preferably by means of a small charge
below the stopping, fired by a fuse.
In order to facilitate the removal of the débris it is preferred that the holes
through which the water is sucked as above described should be deeper than the
other holes, and any pieces too large too pass through the tube will collect at the
bottom of these deeper holes and can then be pulverized by percussion or by
explosive material.
The Invention is applicable to quarrying, driving levels or tunnels, or sinking
pits, and by its use blasting chambers of any desired size can be readily and quickly
formed at any desired depth in the rock, and economy of labour and of explosivo
material is obtained in currying on such operations.

page_text: SPECIFICATION in pursuance of the conditions of the. Letters Patent filed by
the said Edmund Edwards in the Great Seal Patent Office on the 24th May
1882.
EDMUND EDWARDS, of the Firm of Edwards and Co., Patent Agents and
Engineers, of 40, Southampton Buildings, Chancery Lane, in the County of
Middlesex. "IMPROVEMENTS IN METHODS OF EMPLOYING EXPLOSIVE SUBSTANCES
FOR BLASTING ROCK, IN DRIVING TUNNELS OR LEVELS, SINKING SHAFTS, AND
OTHER OPERATIONS OF THE LIKE KIND." A communication from abroad by
Emile Wickersheimer and Leopold Pech, both of Carcassonne, in the Republic
of France.
This Invention lias for its objects novel methods of preparing holes or chambers
in hard rock which it is desired to blast for the purpose of driving tunnels, or
levels, or sinking pits, and of employing gunpowder, dynamite, or other explosive
materials in the holes or chambers so prepared. In preparing such holes or
chambers, it is found to be advantageous that the bottom or end of the hole which
contains the explosive material should be chambered, or of larger size than the
remainder of the hole, and for this purpose expanding or other tools specially
adapted have sometimes heretofore been used. By the present Invention such
chambered or enlarged holes can be prepared and utilized by means of the drills or
tools ordinarily used in mining, and great economy is effected both in the time and
cost necessary for making the holes, and in the quantity of the explosive material
used, a larger quantity of the rock being removed by the process of blasting.
The accompanying Drawing is in illustration of the present Invention. Figure 1
is a section of the rock, in the interior of which a chamber is to be formed to
receive explosive material. a and b are two holes of small diameter drilled in the
rock by ordinary well known means, near and parallel to each other. One of these
holes a is charged with gunpowder or other explosive, and is lightly tamped and
rammed, the hole b remaining empty. The charge in a is then fired, the tamping
being expelled, and at the same time the lower part of the wall or division between
the two holes is broken, as shewn in Figure 2. The powdered débris is partly
expelled by the gas and partly collected at the bottom of the hole b, forming the
mass a, 3. 7, 6, whilst the upper part of the holes remains unfissured.
The proportion between the depth of the holes, their distance apart, and the
quantity of explosive material in a may be varied to suit the character of the rock
and other varying conditions, and in some cases the empty space left will be
sufficient to hold the charge of blasting material. For example, experience has
shown that in hard but fissured granite, with holes about 11 feet deep and about
1 in. diameter, a charge of about 1 pound of dynamite would form a space in
which about 24 pounds of the latter could be placed in a length of about 4 feet.
The capacity of the chamber may be increased by removing the débris remaining
between the holes, as shewn in Figure 2.
For this purpose a lifting and forcing pump is employed by which water can be
forced through a delivery pipe fitted into a, whilst it sucks or draws through
another pipe fitted into b, a suitable reservoir or chamber being provided in the
latter pipe in which the debris settles and collects as it is withdrawn with the
water.
The valves and passages of the pump may be arranged in the ordinary well-
understood way, so that, if desired, in case of any stoppages, the direction of the
current may be reversed, the water being forced into the hole band withdrawn
through the hole a. The pipes described are made preferably of copper, as thin
as possible, and they may be made in separate lengths fitted together and

page_text: connected by bayonet joints, or other convenient means, as shewn in Figures 3
and 4.
Or the breaking of the dividing wall and the expulsion of the débris may be
effected at one operation by placing one or more cartridges at the bottom of the
hole b. The explosion in a will break down the dividing wall and then fire the
charge in b, by which the débris will be expelled.
By these means a chamber is readily produced at a sufficient depth in the body
of the rock which is to be blasted. If a chamber of larger capacity through the
same length is required, a third hole may be drilled, as shown at c in Figure 3, an
opening from the bottom of which may be made into the chamber already formed
between a and b, the débris being removed by a pump, as has been already
described, and similarly a fourth or any number of holes may be added, the chamber
being then enlarged by successive explosions, and the danger of fissuring the rock,
which might occur, especially if the holes were not deep, if the charges in all the
holes were fired simultaneously being avoided.
It is found however that it is better to drill all the holes which are to be used
before breaking down the dividing wall between two of them in the way described;
and in order to preserve the holes which are to be afterwards used, as for instance
the hole c in Figure 3, they are stopped or ramined for a sufficient height, the
stopping being removed after the explosion, preferably by means of a small
explosive charge introduced before the stopping is inserted, and fired by means of
a fuse.
The distance between the several holes a, b, c, d, will vary according to the
diameter of the holes, the length of the chamber to be formed, the nature of the
rock and the character of the explosive material, and in each case it is advisable
that the best conditions should be determined by preliminary experiments. The
direction of the holes should be such that their inner ends are at their proper
distance apart.
To facilitate the removal of the débris it is advisable that the holes through
which the water is to be sucked, as already described, should be deeper than the
remainder, and if there should be any pieces too large to pass through the pipe
they will collect at the bottom of these deeper holes, and can be pulverized either
by percussion or by explosive material.
The Invention is applicable to quarries, and it is found that in the hardest rocks
the distance between the adjoining holes a and b should not exceed about 5 to
6 inches, whilst the distance may be increased as the hardness of the rock
diminishes.
In levels or tunnels, where the object is to make an excavation into which tho
charges in lateral holes will explode, different methods may be adopted for putting
the Invention in practice.
Holes may be drilled parallel with the axis of the level having chambers at a
sufficient depth, which aro charged and fired simultaneously. Or the holes may be
arranged so as to make first a fissure, the chamber being fired afterwards, an
arrangement particularly effective for compact rocks. Or lastly, separate chambers
may be used, the successive discharges forming the desired excavation.
The following formula may be used for calculating the charges for the
chambers :-
==
c = 0.25 h³
Where the weight of dynamite in kilogrammes.
h
drift.
=
the distance in mêtres from the centre of the chamber to the face of the
m = a coefficient varying from 17 to 3, according to the character of the rock.
By the Invention above described, in which implements and materials in
ordinary use only are required, it is possible readily and cheaply to make chambers
as described of any desired form and size, so that the effect of the explosive materials
may be graduated at will in rocks which are to be blasted, and I claim the novel
process for making such chambers such process consisting first of weakening the

page_text: part which is to be blasted by means of holes regularly distributed; second, of
breaking for a sufficient distance the separating walls between such holes; third,
of, if necessary crushing more or less of the resulting débris; and fourth, of with-
drawing, if necessary, the débris from the holes, all substantially as and for the
purposes described and shewn.
In witness whereof, I, the said Edmund Edwards, have hereunto set
and seal, this 24th day of May, in the year of our Lord 1882.
ענון
hand