AN IMPROVEMENT IN THE TAMPING OF BLAST HOLES AND OTHER HOLES SUBJECT TO INTERNAL PRESSURE
Year: 1884

page_text: I, JOHN LEWIS THOMAS of Meridian Place, Chapel Road, Abergavenny, in the
County of Monmouth, Surveyor, do hereby declare the nature of my said invention
for "AN IMPROVEMENT IN THE TAMPING OF BLAST HOLES AND OTHER HOLES
SUBJECT TO INTERNAL PRESSURE" to be as follows:-
The explosive charges for blasting and other charges subject to pressure have
heretofore always been confined in the blast holes by means of "tamping" consisting
generally of clay or wet sand rammed in tightly, and it frequently happens that, in
firing, such tamping is blown out, causing injury both to the miners and to the
mine.
My invention has for its object to obviate this defect and it consists in employing
in the place of the ordinary tamping, two or more wedge shaped blocks of metal
or wood, formed with an external configuration so as to fit the bore hole, and so
arranged that when the charge is fired or subject to pressure, the one block, in being
acted upon by the force of the explosion or other pressure, shall cause the other
part or parts to be wedged tightly in the bore hole, and thus effectually prevent
them from being driven out.
This improved device for tamping may be variously constructed; thus, it may
consist of a pair of folding wedges, which jointly have the required external
cylindrical configuration to fit the bore hole, the one wedge being perforated or
grooved longitudinally for the passage through it of the fuse for igniting the
charge; or there may be two outer wedges and a third one between them or there
may be a double ended wedge piece, with a single ended wedge piece on each
inclined surface thereof, so that any motion imparted to the innermost single wedge
by the explosion or other pressure will tend to wedge the outer single wedge tight.
According to another arrangement a pair of folding wedges are first placed in the
inner end of the blast hole, and after introducing the blasting or other charges, &
second set of folding wedges are placed in the outer end of the blast hole. Thus,
on the ignition of the charge, the force of the explosion being exerted upon the
inner pair of wedges, as well as the outer ones, a very effective wedging action will
be produced in the blast hole assisting the explosive or other force in breaking
down the material. If required, a small quantity of ordinary tamping material
Price CZ1

page_text: may be interposed between the blasting charge and the inner end of the wedges, as
also at the outer end of the wedges, in order to insure a perfect gas-tight closing of
the hole.
The outer cylindrical surfaces of the wedges may either be made smooth or they
may be provided with small ribs or projections, which, in penetrating into the sides
of the blast hole will increase their hold upon the same.
I JOHN LEWIS THOMAS of 100 Woodville Road Cathays Cardiff in the County
of Glamorgan, Surveyor do hereby declare the nature of my invention for THE
TAMPING OF BLAST HOLES AND OTHER HOLES SUBJECT TO INTERNAL PRESSURE
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
The invention consists of a Wedge formed or made up of three or two separate
parts and which parts when placed together form a cylinder. In the first Wedge
of three parts, the centre or middle part is made one end thick, filling as near as 2
possible the circular hole into which it is to be inserted, the other or outside end of
this centre piece is made to taper almost to a thin edge; the two outside, or side
pieces, are made thick on one end and taper to a feather edge on the other.
In the second Wedge of Two parts, the cylindrical form is made up of the two
pieces, or parts, each of which is thick on one end, filling up the blast hole as
near as possible and tapering to a feather edge on the other.
The thick or butt end of each of the Two before mentioned class of Wedges is
first inserted into the blast hole and following is the fine or tapered end of the
other two and one piece respectively, filling up the hole.
The Wedges may be made of Wood, Iron, Steel, Copper, Bruss, or Lead of any 3
suitable length and diameter.
The Cartridge of powder, Dynamite, or Gun Cotton is first placed in the blast
hole, then follows a tamping, composed of Clay, Sand, Coal dust, or mud, three
Inches or more in length, next to explosive; the object or purpose of this tamping
is, that the sudden action of the explosive, after explosion, shall not act directly on 3
the rigid substance composing the wedge. The thick end of the wedge is then
inserted in hole and the two side pieces in the one class of Wedge follows, feather
end first and the one piece in other class of Wedge, feather end also first, the
butt, or thick outside end or ends are then sharply tapped and tightened up.
In each class of Wedge a hole sufficiently large is made through the Centre or 4
side to admit of a safety Fuse passing through or by side, through the tamping to
explosive.

page_text: The force of the explosive closes the Wedges still tighter and by this confined
force, the Coal, Rock, Clay, Shale, or other material into which the hole is bored, is
dislodged or brought down.
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,
Wedge arrangements for tamping blast holes substantially as hereinbefore
described.
Dated this Nineteenth day of November One thousand Eight hundred and
c
JOHN LEWIS THOMAS.