Improved Method and Means for Obtaining Increased Safety in Shot Firing in Coal Mines and other Mines.
Year: 1898

page_text: Date of Application, 4th Jan., 1898
Complete Specification Left, 9th Sept., 1898-Accepted, 5th Nov.,
1898
PROVISIONAL SPECIFICATION.
Improved Method and Means for Obtaining Increased Safety in
Shot Firing in Coal Mines and other Mines.
We, CHARLES HERBERT CURTIS, of the Firm of Curtis's & Harvey, of 74, Lombard
Street, in the City of London, Gunpowder Manufacturers; DAVID JAMES METCALFE
and CLEMENT LEIGH WATSON SMITH, Managing Directors of the Firm of John
Hall and Son Limited, of 79, Cannon Street, in the City of London, Gunpowder
Manufacturers; ANDREW FULLER HARGREAVES, General Manager, and ALFRED COPLEY
PEARCY, London Manager of the Firm of Hay Merricks & Co. Limited, of Roslin,
Midlothian, Gunpowder Manufacturers, do hereby declare the nature of this invention
to be as follows:-
According to this invention we provide in front of the gunpowder or other explo-
sive blasting charge suitable means for extinguishing the flame or incandescent
particles of the said explosive charge or for lowering the temperature of same, when
fired for blasting purposes in localities such as dangerous coal and other mines. We
combine in one cartridge the explosive with the aforesaid means for exerting an
extinguishing or cooling action when the explosive is fired so as to be readily avail-
able for transport, storing and immediate application when wanted but so as that
the explosive and the cooling means are not formed into a mixture but kept separate
or intact from each other by a paper diaphragm or the like.
As cooling means we may use any such that may be found suitable for the pur-
pose. We may however as an example according to experience so far gained
mention the ingredients hereinafter named which are used separately or mixed two
or more or all of them in a granular form and enclosed in a paper or other receptacle
which is made up in one cartridge with the powder or other explosive but separated
therefrom by a paper diaphragm or the like. We may thus inake a cartridge in
which the powder charge is first run into the paper or other case and then a paper
cardboard or other disc provided with a tube (for the passage of the fuse or other
igniting device) is placed on the top of the powder, whereupon the granular cooling
ingredients are filled in on the disc and round the tube; the cartridge case is then
closed on it and the cooling ingredients thus kept separate from the explosive.
The cooling ingredients are: sulphate of alumina potash alum, ammonia alum,
oxalate of ammonium, borax, and sulphate of ammonium separately or combined.
l dow of Tonuary 1808
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.

page_text: Improved Method and Means for Obtaining Increased Safety in
Shot Firing in Coal Mines, and other Mines.
We, CHARLES HERBERT CURTIS, of the Firm of Curtis's & Harvey, of 74, Lombard
Street, in the City of London, Gunpowder Manufacturers; DAVID JAMES METCALFE
and CLEMENT LEIGH WATSON SMITH, Managing Directors of John Hall & Son
Limited, of 79, Cannon Street, in the City of London, Gunpowder Manufacturers;
ANDREW FULLER HARGREAVES, General Manager, and ALFRED COPLEY PEARCY,
London Manager of Hay, Merricks & Co. Limited, of Roslin, Midlothian, Gun-
powder Manufacturers, 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:―
According to this invention we provide in front of the gunpowder or other explosive
blasting charge suitable means for extinguishing the flame or incandescent particles
of the said explosive charge or for lowering the temperature of the same when
'fired for blasting purposes in localities such as dangerous coal and other mines. We
combine in one cartridge the explosive with the aforesaid means for exerting an
extinguishing or cooling action when the explosive is fired so as to be readily
available for transport storing and immediate application when wanted but so that
the explosive and the cooling means are not formed into a mixture but kept separate
or intact from each other by a paper diaphragm or the like.
We may
As cooling means we may use any of the ingredients hereinafter named which are
used separately or mixed two or more or all of them in a granular form and enclosed
in a paper or other receptacle which is made up in one cartridge with the powder or
other explosive but separated therefrom by a paper diaphragm or the like.
thus make a cartridge in which the powder is first run into the paper or other case
and then a paper cardboard or other disc provided with a tube (for the passage of the
fuse or other igniting device) is placed on the top of the powder whereupon the
granular cooling ingredients are filled in upon the disc. The cartridge case is then
closed on it and the cooling ingredients kept separate from the explosive.
The cooling ingredients are sulphate of alumina potash alum amonia alum oxalate
of amonium borax and sulphate of amonium separately or combined. We have found
that oxalate of amonium in a granular condition as hereinafter more particularly
'described is especially suitable for our purpose.
We are aware that the salts of oxalic acid have been proposed to be used as a
cooler or for the reduction of flame in conjunction with various high explosives
requiring detonation also that attempts have been made to cool and extinguish the
flame of an explosive by the liberation of carbonic acid provided under pressure in a
suitable receptacle adjacent to the explosive.
Also that it has been attempted to use salts containing quantities of water of
crystallization such as carbonate of soda (soda crystal) as a coating or receptacle for
the explosive.
Also that it has been proposed to provide a stemming or tamping to be rammed
into the bore hole with the explosive consisting of various flame quenching
*substances.
Also that it has been proposed to intermix or incorporate with high explosives
requiring detonation containing nitro-glycerine or other nitro compound salts such
as soda crystals sodium carbonate potash alum amonia alum sodium sulphate
magnesium sulphate iron sulphate copper sulphate sodium phosphate and magnesium
phosphate and sodium phosphate.
Also that various attempts have been made to surround the explosive with water
or with water held by other substances.

page_text: Also that oxalate of amonium sulphate of alumina potash alum amonia alum
borax and sulphate of amonium have been proposed to be used incorporated or
intermixed so as to form part of the explosive charge.
But from experience it has been found that none of these contrivances succeed and
that they fail for the following reasons amongst others.
Either the cooling or flame extinguishing materials have only been used with or
as part of the explosive charge and generally with a charge of some high explosive
requiring to be exploded by detonation. Gunpowder differing in its character from
the high explosives leaves after explosion a considerable percentage of solid
particles which become incandescent and which it has hitherto been impossible to
cool down or extinguish sufficiently rapidly to render them safe in the presence of
coal dust or inflammable gas. In the cases where such materials as we employ have
been contemplated for use with or as part of gunpowder they have been either
incorporated with the gunpowder and have become an adulteration and reduced the
disruptive power of the explosive and rendered it of little value or where other
substances of a somewhat similar character have been used they have been of such
a nature that they could not be kept as part of or in close proximity to the gunpowder
without causing deterioration thereof either from their efflorescent or deliquescent
nature.
Our intention has been to provide as we claim to have successfully done in connection
with gunpowder a means of combining in one cartridge (so that the explosive cannot
be used without the cooling ineans) a substance which will act as a cooler and
extinguisher of flame or incandescent particles whilst at the same time it leaves the
gunpowder intact and free to exert its proper disruptive action the cooler being of
stable character and neither likely to change itself nor bring about any change in the
gunpowder and so placed in a cartridge case as to be in the closest proximity to the
gunpowder and yet separate therefrom.
From experience we have found that one part by weight of the cooling agent to two
parts by weight of gunpowder is a good proportion but we do not restrict ourselves to
these proportions and either greater or less proportions may be used.
In order that the said invention so far as the same consists in the use of the
cartridge may be more fully understood we will describe the same by means of the
accompanying drawings.
Fig. 1 shews a drawing of the cartridge.
Fig. 2 is a drawing of the end piece through which the fuse passes.
Fig. 3 is a drawing of the diaphragm.
Fig. 4 is a sectional view of the same.
Fig. 5 is a sectional view of the cartridge.
A is the portion of the cartridge which contains the powder.
B is the disc or diaphragm constructed as shewn in the form of a cardboard ring
supporting a membrane of inuslin, paper or other suitable separating material. In
place of a diaphragm constructed as shewn we might use a disc of paper or other
easily disrupted fabric supported and retained in place in any suitable manner.
C is the channel or passage for the reception of the fuse.
D is the receptacle for the cooling material charged with crystals of oxalate of
amonium or equivalent salt as above mentioned in a coarsely granulated condition so
as to leave a large proportion of interstitial space.
E is the end piece placed on the top of the cooling material to complete the
cartridge.
The cartridge may be made of paper or any other suitable material usually
employed for the purpose of making cartridges.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. In a blasting cartridge the combination with gunpowder in the manner herein-
before described and without intermixture therewith of a cooling agent consisting of

page_text: granulated oxalate of amonium sulphate of alumina potash alum amonia alum borax
or sulphate of amonium separately or combined as hereinbefore described.
2. The hereinbefore described blasting cartridge charged with gunpowder and with
a cooling agent for extinguishing the flame and incandescent particles of the gun-
powder which cooling agent consists of the materials herein before enumerated for
that purpose or of some or of one of them granulated and placed in the cartridge
substantially as hereinbefore described and shown.
3. The use in a blasting cartridge in which gunpowder is employed as the blasting
agent of granulated oxalate of amonium treated and disposed as hereinbefore described
and shewn.
4. A blasting cartridge containing the materials hereinbefore mentioned and con-
structed and arranged as herein before described and shewn by the accompanying
drawing.