Improvements in or relating to Safety Tamping for Explosives used for Blasting Operations in Coal and other Mines, and in Apparatus for use in connection therewith.
Year: 1897

page_text: Complete Specification Left, 29th June, 1898-Accepted, 6th Aug., 1898
Improvements in or relating to Safety Tamping for Explosives
used for Blasting Operations in Coal and other Mines, and in
Apparatus for use in connection therewith.
I, EDWIN STANLEY CLARK, of Oak Alyn, near Wrexham, in the County of Denbigh,
Colliery Owner, do hereby declare the nature of this invention to be as follows:-
This invention relates among other things to a safety tamping for explosives which
can be used even with an iron rod without fear of igniting the charge, and which will
not only absorb or utilise the flame or heat generated by the explosion, but will also
actually increase the force of an explosion by giving out free gas, thus economising
the explosives used.
In carrying my invention into effect, I place both at the back and front of the
charge, a cylinder or cone of a chemical salt or combination of salts, such as soda,
potash and ammonia, having a large amount of water of crystallization, or other water
in combination therewith unstable at low temperature, to which one per cent. of
ferric oxide or other strongly staining matter may be added. The addition of this
latter ingredient however is entirely optional. In practice I use the cylinders or
cones with holes through the centre or to one side to allow of the passage of the
fuse, placing cylinders or cones of one or more inches in depth and the diameter of
the bore hole, at the back of the charge and another cylinder or coue in front of the
charge, more or less according to the weight of the charge without any intervening
material or wad. This latter is preferably threaded on to the fuse, and placed in the
bore hole with the charge.
The kind of salt which I prefer to use is mono-carbonate of soda or crystal
soda, or a combination of this salt with other salts potash and ammonia, first because
it is a cheap salt and so abundant as to be within the reach of all users of explosives,
and secondly because it has a large quantity of water of crystallisation. As
however these salts are liable to give out water and change to a comparatively
anhydrous powder by long exposure to the air, I may wrap these cylinders in
waterproof wrappers, such as tinfoil, oil paper, parchment paper or the like, or
may even coat them with a thin coating of indiarubber, guttapercha or other
waterproof material which can be removed from them before use or not as found
most desirable. .
The solid cylinders or cones are prepared as follows:-Granulated mono-carbonate
of soda and ferric oxide is prepared by filling into small slightly tapered metal
cups which are sunk in trays or holders of suitable size, the bottom of the cup
being closed, and the sides of the trays closed in. On the upper tray a third
one is made to fit and having fitted into it small hollow tubes of any non-easily
oxidised metal, these tubes being so arranged to fit into centre of each cup.
When the cups have been filled with granulated soda crystals, melted mono-
carbonate is run on to the tray, and each cup is filled up in the interstices of
the granulated crystal. The cups are then allowed to stand in a cool temperature

page_text: to assist recrystallisation for 24 hours after which the trays have turned into, and
between them a little live steam, or hot water, and hot water is also put into
the third tray with the hollow tubes in it, the effect being to soften the outer
surface of crystal in cups, and around the hollow tubes, and enable the latter to
be withdrawn from the cylinders and the cylinders from the tapered cups. They
are then put aside in boxes or barrels ready for use.
Instead of using the mono-carbonate of soda in the form of cylinders it may
be used in granulated form, placed both at the back of the explosive and in the
front without any intervening material or wad. In such case bowever I use a filler or
rammer which may be constructed of a brass tube to which is screwed an iron
tube by preference about five or six feet in length. Inside this iron tube is an
iron rod secured to a brass or copper plunger fitting loosely the brass tube
aforesaid and, having a handle at the end. The end of the plunger is coned and
when pushed forward by the iron rod is projected out at the end of the brass
tube.
Granulated crystal is filled into the brass tube by hand in such quantity as
may be required, one to four inches at a time. The filling and ramming device is
then pushed into the blast hole and when the bottom of the hole is reached the iron
rod with its plunger head is pushed forward or held by the band, while the iron tube
is drawn back. The granulated crystal is by that means ejected into the back of the
blast hole, and the rod is used to ram it up tightly to the end. The explosive with
the fuse attached is pushed into the hole by the use of the same rammer.
rammer being withdrawn, again filled or charged with the granulated compound,
and again passed into the hole, and its contents discharged as in the first instance.
By this means the explosive intervenes between two charges of the compound, and on
to the latter charge of compound I put about 9 inches of arenaceous clay stemming,
kiln dried but not burnt, which is put in in pieces about 3 inches long and of a
diameter equal to nearly that of the blast hole. The rainner is used to put in each
piece separately, and the cone shaped head of the plunger of same breaks up the end
of the clay cylinder and so fills the blast hole perfectly, and is calculated to
prevent blown out shots or reduce the risk of same. The clay cylinders are made
from clay mixed with sand, or other arenaceous and uninflammable material, they
being formed in moulds or dies and then cut into lengths and heated to a high
temperature to evaporate out all moisture.
Dated this 1st day of Santambar 1907
The
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
Improvements in or relating to Safety Tamping for Explosives
used for Blasting Operations in Coal and other Mines, and in
Apparatus for use in connection therewith.
I, EDWIN STANLEY CLARK, of Oak Alyn, near Wrexham, in the County of Denbigh,
Colliery Owner, 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 among other things to a safety tamping for explosives,
which can be used even with an iron rod without fear of igniting the charge, and
which will not only absorb or utilise in large part the flame or heat generated by the
explosion, but will also actually increase the force of an explosion by giving out free
gases thus economising the explosives used.

page_text: Since filing my Provisional Specification I have considerably improved upon the
vention therein set forth and as the law prescribes that the best mode known to me
carrying the invention into effect should be disclosed I will describe the invention
applied for but with all iny latest improvements added as set forth in my later
rovisional Specification of the 21st of May, 1898, No. 11674, but I hereby give the
blic notice that the improvements mentioned but not claimed in this Specification
not covered by my Provisional Specification are not dedicated to the public,
ut are covered by my later Provisional Specification which it is my intention
complete.
Referring to the accompanying drawings.
Figure 12 continuation of rod T and tube U.
Referring to Figures 6, A is the face of a seam of coal, B bore hole, C prop,
C₁
sprags, D fuse, E the explosive, I place both at the back and front of the charge E,
a cylinder F of a chemical salt or combination of salts such as those of soda, potash
and ammonia, which has a large amount of water of crystallization, or other water in
combination with it unstable at low temperature, to which salt one per cent. of ferric-
oxide or other strongly staining matter may be added. The addition of this latter
ingredient however is entirely optional. In practice I use cylinders or cones F with
holes through the centre or to one side to allow of the passage of the fuse D, and in
practice I prefer these holes to be about five-eighths of an inch in diameter, and also
prefer to have the cylinder very loosely fit the hole as set forth in Figure 5, as by this
ineans I find the flame and hot products of explosion instead of blowing out the
chemical tamping, pass up alongside of it for its entire extent, and disassociate the
water from the chemical tamping throughout forming high pressure steain. It also
appears to disassociate the carbonic anhydride. The cylinders or cones are usually
one or more inches in length and preferably of considerably less diameter than the
bore hole. At the back of the charge E there is usually a short length of cylinder F,
but the principal amount of chemical tamping F is placed in front of the charge E in
which case it is placed without any intervening material or wad. The cylinders are
preferably threaded on to the fuse D and placed in the bore hole B with the charge E,
but in any case where the cylinders are likely to be broken in being placed in
position, they can be inserted by means of the tool hereinafter described used for
placing in position the granulated salt.
The kind of salt which I prefer to use is mono-carbonate of soda or soda crystals as
it is commonly termed, or a combination of this salt with other salts of soda, potash
or ammonia. The following is a good recipe, hydrated monocarbonate of soda
97 per cent., sulphate of soda 2 per cent., ferric oxide 1 per cent. The object of
using hydrated carbonate of soda is that it is a cheap salt easily procurable and it
contains a very large amount of water of crystallization. As however nearly all these
bydrated salts are liable to give out water and change to comparatively anhydrous
powder by long exposure to the air, I may wrap these cylinders in waterproof
wrappers such as tin-foil, oil paper, parchment or the like, or even coat them with a
thin coating of india-rubber, gutta percha or other waterproofing material. These
can be removed from them before use or not as found most desirable.

page_text: The method of preparing the hollow cylinders and the apparatus for it are as
follows:-
Granulated monocarbonate of soda with a little sulphate of soda and ferric oxide is
filled into the slightly tapered metal cups P shown in section in Figure 9 and in plan
in Figure 7. These cups are sunk in trays or holders L. To the tray L is secured
the bottom M (perforated with holes) having fitted in them small hollow tubes Q
of any non-easily oxidised metal, these tubes being arranged to fit in the centre of
each cup P. When the cups have been filled with the granulated soda crystals packed
in around the tube, a saturated solution of monocarbonate is run in, thus filling up
the interstices of the granulated crystals in each cup. The whole are then allowed
to stand in a cool temperature to assist recrystallisation for about 24 hours, after
which a little live steam is turned into each bar, and into the bottom if made hollow
or is otherwise made to surround the cups for a short time. Hot water can be used
instead of steam. The result is that the outer surface of the crystalline matter in the
cups and around the hollow tubes which are also permeated by the steam is melted,
and on the frame of bars being turned over the cylinders fall out or they can be
lifted out on the tubes. They are then left to cool and can be put away in boxes or
barrels for use.
Instead of using the mono-carbonate of soda in the form of crystals it may be used in
granulated form placed both at the back of the explosive and. in front without any
intervening material or wad. I prefer however making it in the cylindrical or pris-
matic form as described as it is very desirable that the gases should permeate round
the crystalline material as freely as possible. Where however I use a granular material
and even when using cylinders I prefer to employ a filler or rammer such as set forth
in Figures 11 and 12 in which V is a brass tube to which is screwed an iron tube U.
Inside this iron tube is the iron rod T secured to a brass or copper plunger. W fitting
loosely the brass tube aforesaid and having a handle at the end. The end of the
plunger is preferably coned as shown, and when pushed forward by the iron rod is pro-
jected out at the end of the brass tube. X is a light cap that can be used if required.
Granulated crystals, or if cylinders be used, the cylinders, are filled into the brass
tube by hand in such quantity as may be required. The rammer is then pushed into
the blast hole, and when the bottom of the hole is reached the iron rod with its plunger
head is pushed forward or held by the hand while the iron tube with its brass attach-
ment is drawn back. The granulated crystals or the cylinders are by this means placed
in the back of the blast hole, or if the tubebe long enough the tamping back ofthecharge
the charge and the tamping in front of the charge are all placed in together, by means
of this rammer or as set forth in the Provisional Specification it can be done in three
charges. When the rammer has been withdrawn arenaceous clay stemming is rammed
in, in the usual manner which is put in in pieces about 3 inches long and of a
diameter equal to nearly that of the blast hole. The rammer is used to put in each
piece separately and the cone shaped head of the plunger of same breaks up the end
of the clay cylinder and so fills the blast hole perfectly, and is calculated to prevent
blown out shots or reduce the risk of same. The clay cylinders are made from clay
mixed with sand or other arenaceous material, they being formed in moulds or dies
and then cut into lengths and heated to a high temperature to evaporate out the
moisture.
All the other reference letters appearing on the drawings that are not referred to in
this Specification, will be referred to in the Complete Specification of my later
application No. 20,223 of 1897.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improvement in safety tamping in mines, which consists of solid cylinders,
prisms or other pieces of highly hydrated salt such as described arranged in a bore
hole with central or other passage or passages, whereby the products of combustion

page_text: can permeate this stemming and give up heat in liberating gaseous products from
the stemming substantially as described.
2. The method of forming solid pieces of carbonate of soda or other like salt for the
purposes described, which consists in filling into moulds crushed or small crystals
filling the interstices with hot saturated solution, allowing the latter to re-crystallise
and then freeing the block by means of heat.
3. The tool for placing the tamping in position substantially as described and
illustrated.
Dated this 90th den of Tune 1000
W. P. THOMPSON & Co.,
Patent Agents of Liverpool, Manchester, Birmingham and London.