Improvements in or relating to the Exploding of Blasting Charges in Mines.
Year: 1894

page_text: Date of Application, 16th July, 1894-Accepted, 18th Aug., 1894
COMPLETE SPECIFICATION.
Improvements in or relating to the Exploding of Blasting Charges
in Mines.
I, LUDWIG JAROLJMEK, of Prague, Bohemia, in the Empire of Austria, do
hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement :-
This invention relates to a method of causing the automatic explosion of the
explosive charge in a borehole, without employing a fuse, quickmatch, electric wire,
friction appliance or other connection of the kind, and above all without the
workman having in any way to manipulate a light or strike a lucifer-match.
The object is attained by means of a special cartridge, employed in my process,
to which water (for tamping) is conveyed in such manner as to entirely surround
and cover the cartridge; and also my means of a particular mode of procedure
during the tamping of the borehole.
The cartridge varies according to the essential principle upon which it is based;
so that the chemical reaction set up in the cartridge is due ;-
1. Either to the heat developed thereby ;
2. Or to the resulting enlargement in volume (with outward pressure): in either
case bringing about the explosion of the charge.
Hence arise three distinct cases, with three corresponding arrangements, according
to whether the explosion is induced,
A. by the heat, indirectly, (by the agency of a detonator).
B. by the heat, directly, (without a detonator).
C. by pressure following on increase of volume.
In the first case (A), a metallic cap, formed by the combination of two separate
parts, is inserted in the charge, and having its upper portion (with its mouth
downwards) containing a fulminate priming which detonates at a comparatively
low temperature say 120 degrees centigrade. This priming is surrounded by a
cylindrical case filled with anhydrous lime (or burnt chalk); instead of which,
however, anhydrous baryta, strontia, potash, soda, or muriate of lime may be used,
without departure from the essential principles or scope of the invention.
The cylinder of lime above mentioned, with the explosive cartridge beneath it,
is inserted into a porous jacket, made of some suitable material such as felt, hemp-
fibre, cotton webbing such as is used for wicks or the like; and even clay and
other materials which are permeable by water may be used for encasing the cylinder
and cartridge.
By its formation, this jacket is well adapted to circumscribe and retard the
admission of water to the caustic or quick-lime, so that it is limited to the quantity
required only. By this slow admission of water a gradually increasing heat is
developed (as the slaking proceeds) in the lime, which in the course of from one
to three minutes, suffices to ignite the upper detonator, so as to fire the lower
detonator and with it the explosive charge.
Figure 1 of the accompanying drawings shows this arrangement, wherein a¹ all
indicates the detonating cap with an exceedingly sensitive priming, i.e. which
"flashes"
or explodes at a comparatively low temperature, the two parts being
put together only just prior to placing the explosive-cartridge in the borehole,
before tamping the latter for the shot; b is the heat-generating mass of anhydrous

page_text: lime or equivalent; c the porous jacket, which is to be closed by the operator
immediately after the insertion of the explosive cartridge, d; and e is the water-
tamping of the bore-hole:
In the second case (B), the mass of anhydrous lime encloses and surrounds (but
without a detonator) the upper part of the explosive substance. The heat-
generating mass in this case is composed of two parts separated by a bag or pocket
'made of a metal or metallic compound melting at about 100 degrees centigrade,
and filled with an acid, such as anhydrous sulphuric or phosphoric acid in fixed
form. After the slaking of the lime by the infiltrated water which operation melts
the metallic pocket and sets the acid free, the chemical reactions and combinations
which necessarily result, and consequent high temperature evolved (over 300 degrees
centigrade) bring about the explosion of the explosive cartridge.
This arrangement is shown in Figure 2, wherein a shows the metallic bag or
pocket filled with acid in a fixed form, which I call the "acid capsule or cachet";
bis the heat-generator; c is the porous jacket; d the explosive cartridge, whereof
the outer shell is preferably paper and wrapped round or enclosing an inner shell
or case formed of some permeable material which is a good heat conductor.
In the third case (C) the function of the mass of lime is, on the infiltrated water
combining with it by means of the consequent gradual (riz. in the course of about
1 minutes) swelling or expansion of the hydrated-lime within the jacket, to bring
strong pressure into action in an upward direction. Thereupon, by means of a
wire, an ignition cachet or capsule is rent asunder, which at once detonates the
explosive cartridge beneath. To this end, the expansion-cylinder is strongly pressed
and tightly enclosed in the porous jacket which, at the same time, has great power
of resistance, and is secured at one end to the wire and at the other end to a plug
separating the mass of lime from the explosive material. The ends of the wire as
well as the ignition-device are concealed in a suitable hollow in the plug.
Figure 3 illustrates this arrangement, a being the expansion-cylinder, 6 the
porous jacket, c the plug, d the wire, e the ignition capsule or cachet, f a plug of
fusible metal for fixing the wire in the hollow of the plug and making a water-tight
closure to the opening, the explosive cartridge, whereof the jacket breaks joint
with or overlaps the detonator h.
The mode in which the ignition of the explosive is brought about is as follows ;-
The borehole is tamped with water, which in the case of holes bored downwards is
effected by simply pouring the water in the hole, and for holes bored upwards by
the use of a pump or injector, which, while abstracting the air, forces the water
up into the borehole until it reaches the charge. When the bore is made in rock,
coal, etc., in fiery mines liable to the irruption of fire-damp the work is so executed
that the explosive material is entirely surrounded by the water.
Figures 4 and 4B illustrate this alternative arrangement of water-injector,
wherein indicates the explosive, 2 the cartridge, as used in this process, 3 the
tamping water, 4 a preferably cast-steel stopper provided with two longitudinal
grooves, 5 the water-supply pipe, 6 a long reed, quill tube or equivalent extending
from the charge downwards for the escape of the air when the tamping water is
forced into the bore, 7 a water-cistern fitted with a pinch or compression stop-cock,
8 a closed cylinder filled with compressed air, 9 a temporary cross-beam or prop,
for the protection of the water injector.
Figure 5 illustrates the arrangement, when it is expedient that the explosive
material and cartridge should be completely surrounded with water.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. A process wherein for the purpose of firing a blasting charge besides the
explosive itself such additional solid and fluid materials (such as quick-lime
anhydrous sulphuric acid and water or equivalent) are also used in the charge as
to set up chemical reaction and form compounds whereby.an increase of temperature

page_text: or volume and pressure is generated so as to cause, directly or indirectly the
explosion of the charge the charge being partly or wholly surrounded with water.
2. Effecting the explosion of a blasting charge by causing water to act on quick
lime substantially as described.
3. Effecting the explosion of a blasting charge by causing the heat resulting
from the action of water upon quick lime to melt a fusible capsule containing acid
thereby engendering sufficient heat to fire the explosive charge.
Dated GIS ay or y
W. P. THOMPSON & BOULT,
Agents for the Applicant.
W. P. THOMPSON & BOULT,
Agents for the Applicant.