Minerals or Rocks and in Apparatus Employed therefor.
Year: 1887

page_text: Date of Application, 4th Jan., 1887.
Complete Left, 16th Sept., 1887
Complete Accepted, 18th Oct., 1887
Minerals or Rocks and in Apparatus Employed therefor.
We, LEOPOLD PLOм, Mining Engineer of Retinne and JULIEN D'ANDRIMONT,
Engineer, of Liège, both in the Kingdom of Belgium do hereby declare the nature of
this invention to be as follows:-
According to our invention in place of merely forming a cylindrical bore hole in
the rock to be blasted, into which the explosive compound or other means for
producing pressure is introduced, as heretofore, we form a considerable enlargement
at or near the end of the bore-hole, into which the explosive or other charge is
introduced, so that, the bore-hole being suitably closed by tamping, and the charge
fired, the explosive force or pressure, instead of being expended against the sides of
the cylindrical bore hole at right angles to the axis thereof, and consequently resulting
in great measure in a mere crushing or pulverising action, is exerted against the
surfaces of the enlargement in a direction parallel or nearly so to the axis of the bore
hole, with the result that the mass of rock situated between the enlargement and the
face of the working is blown outwards by the explosion, and thus the explosive force
or pressure is much more effectively and economically utilised than heretofore.
Various means may be employed for producing the said enlargement of the bore
hole; by way of example we will describe an arrangement for the purpose, referring
to the accompanying drawing in which Fig. 1 shews a longitudinal section of a
cutting implement with the tool for cutting the enlargement expanded, Fig. 2 shews
part of the implement with the cutters drawn inwards, and Fig. 3 shews a section of
the bore hole with enlargement, charged with the explosive and closed by tamping.
The cutting implement consists of a metal tube D in which is a helically formed
stem B having at its inner end one or more cutting tools A A consisting of serrated
arms pivotted to the stem B, and capable of either lying in the folded position Fig. 2,
or being made to protrude through slits in the tube D, as at Fig. 1. At the outer
end the stem B is provided with a screw threaded part E, fixed thereon, which screws
into the correspondingly threaded part F of the tube; this part is rotatable upon the
CD 017

page_text: inner part of the tube, being connected thereto by pins ci on the one part entering a
circular groove on the other part.
In commencing operations, the abovo described implement is introduced into the
previously formed cylindrical bore hole, the part E of the stem B being at the time
screwed into F, thereby causing the stem B to push the tools A into the folded
position Fig. 2, such inward motion of the stem being effected by rotating the screw
threaded tube or sleeve F while D and B remain stationary.
When the implement has been inserted, the operator holds the sleeve F stationary
with one hand, and, by means of a crank handle fitted on to the square end C of the
stem B, rotates the latter, together with the tools A and tube D, whereby the threaded
part E will be made to gradually screw out of the tube F, thus causing the stem B to
draw outwards the inner ends of the tools A, the free ends of which being gradually
pushed out of the tube by coming in contact with the ends of the slots » and
eventually assuming the position at Fig. 1. During this motion, tho serrations of
the arms, in being pressed forcibly against the surface of the rock with which they
come in contact, will gradually grind this away and thus form the cavity M shown at
Fig. 3. Should the rock offer too much resistance during this operation to allow of
the full advance of the tools during each rotation due to 'the pitch of the thread E,
the operator can regulate such advance at pleasure, by allowing the sleeve F to slip
more or less in his hand while rotating the stem B.
The pulverised rock will enter the tube D through the slots s, s, v, and will be
conveyed forward by the helical form of the stem B so as to escape through slits g in
the front protruding end of the implement. When the cutting of the cavity M has
been completed, the stem is again moved inwards so as to withdraw the tools A A, by
rotating the sleeve F, after which the implement is withdrawn and the blasting
charge is introduced, by preference only to such an extent as to fill the lower part of
the cavity M, and the fuze I is by preference fitted in a wood plug N, being made to
pass through a transverse boring thereof, and knotted at the lower end, as shewn at
Fig. 3; the fuze is so arranged that when the plug is inserted the point at which the
fuze fires the charge will be situated at about the middle of the charge. The plug N
being inserted, the hole is closed by tamping K. By inserting the plug right across
the cavity M causing it to enter a corresponding bore hole on the other side, any
tendency to blow out through the bore hole will be prevented, as the pressure of the
explosion will only be effected in a transverse direction upon the circuinference of the
plug and not in an axial direction.
Should other means, such as compressed gases or liquids &c. be employed for
effecting the requisite pressure in the cavity in place of an explosive compound, the
means of introducing the same and bringing them into action would of course have
to be modified accordingly.
Dated this 4th day of January 1887.

page_text: COMPLETE SPECIFICATION.
Improvements in Blasting or Breaking Down Coal and other
Minerals or Rocks and in Apparatus Employed therefor.
We, LEOPOLD PLOM, Mining Engineer of Retinne, and JULIEN D'ANDRIMONT,
Engineer of Liege, both in the Kingdom of Belgium, 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 our invention, in place of merely forming a cylindrical bore hole in
the rock to be blasted, into which the explosive compound or other means for
producing pressure is introduced, as heretofore, we form a considerable enlargement
at or near the end of the bore hole into which the explosive or other charge is
introduced, so that the bore-hole being suitably closed by tamping and the charge
fired, the explosive force or pressure, instead of being expended against the sides of
the cylindrical bore-hole at right angles to the axis thereof, and consequently resulting
in great measure in a mere crushing or pulverising action, is exerted against the
surfaces of the enlargement in a direction parallel or nearly so to the axis of the bore-
hole, with the result that the mass of rock situated between the enlargement and the
face of the working is blown out by the explosion; and thus the explosive force or
pressure is much more effectively and economically utilised than heretofore.
Various means may be employed for producing the said enlargement of the bore-
hole; by way of example, we will describe an arrangement for the purpose, referring
to the drawings accompanying our Provisional Specification. Fig. 1 shews a longi-
tudinal section of a cutting implement with the tools for cutting the enlargement
expanded. Fig. 2 shews part of the implement with the cutters drawn inwards, and
Fig. 3 shews a section of the bore-hole with enlargement, charged with the explosive
and closed by tamping.
°
The cutting implement consists of a metal tube D in which is a helically formed
stem B having at its inner end one or more cutting tools A A, consisting of serrated
arms pivotted to the stem B and capable of either lying in the folded position, Fig. 2,
or being made to protrude through slots, ss. in the tube D as at Fig. 1. At the outer
end, the stem B is provided with a screw threaded part E, fixed thereon which screws
into the correspondingly threaded part F of the tube; this part is rotatable upon the
inner part of the tube, being connected thereto by pins c, e, on the one part entering
a circular groove on the other part.
In commencing operations, the above described implement is introduced into the
previously formed cylindrical bore hole, the part E of the stem B being at the time
screwed into F thereby causing the stem B to push the tools A into the folded position
Fig. 2, such inward motion of the stem being effected by rotating the screw threaded
tube or sleeve F while D and B remain stationary.
When the implement has been inserted the operator holds the sleeve F stationary
with one hand, and, by means of a crank-handle fitted on to the square end C of the
stem B rotates the latter, together with the tools A and tube D whereby the threaded

page_text: part E will be made to gradually screw out of the tube F, thus causing the stem B to
draw outwards the inner ends of the tools A, the free ends of which being gradually
pushed out of the tube by coming in contact with the ends of the slots o and
eventually assuming the position at Fig. 1. During this motion, the serrations of
the arms in being pressed forcibly against the surface of the rock with which they come
in contact, will gradually grind this away and thus form the cavity M shewn at
Fig. 3. Should the rock offer too much resistance during this operation to allow of
the full advance of the tools during each rotation due to the pitch of E, the operator
can regulate such advance at pleasure, by allowing the sleeve F to slip more or less in
his hand while rotating the stem B.
The pulverised rock will enter the tube D through the slots s, s, and will be
conveyed forward by the helical form of the stem B. so as to escape through slits g in
the front protruding end of the implement. When the cutting of the cavity M. has
been completed, the stem is again moved inwards so as to withdraw the tools A A, by
rotating the sleeve F, after which the implement is withdrawn and the blasting charge
is introduced, by preferance only to such an extent as to fill the lower part of, the
cavity M, and the fuse I is by preference fitted in a wood plug N, being made to pass
through a transverse boring thereof, and knotted at the lower end, as shewn at Fig. 3;
the fuse is so arranged that when the plug is inserted the point at which the fuse
fires the charge will be situated at about the middle of the charge. The plug N being
inserted the hole is closed by tamping K. By inserting the plug right across the
cavity M causing it to enter a corresponding bore hole on the other side any tendency
to blow out through the bore hole will be prevented as the pressure of the explosive
will only be effected in a transverse direction upon the circumference of the plug and
not in an axial direction.
Should other means, such as compressed gases or liquid &c. be employed for
effecting the requisite pressure in the cavity in place of an explosive compound, the
means of introducing the same and bringing them into action would of course have
to be modified accordingly.
Having now particularly described, and ascertained the nature of this invention
and in what manner the same is to be performed, we declare that what we claim is :-
1. In blasting for breaking coal or other rock, expanding the bottom of the blast
hole into a cavity of approximately spherical form, and charging the expanded cavity
with the explosive, substantially as and for the purpose set forth.
2. The apparatus substantially as herein described for forming the expanded cavity
in a blast hole, consisting of the tube D with its openings sand the revolving
stem B carrying the pivotted cutting tools A, in combination with the screw thread
on B and the nut F.
3. In the apparatus referred to in the preceding claim, in combination with the
openings and g of the tube D the helical stem B for conducting out the debris
of boring.
4. The arrangement of the fuse in a plug N so as to fire the middle of the charge
as and for the purpose set forth.