A New or Improved Method of and Means for Blasting Rocks and the like.
Year: 1899

page_text: Date of Application, 3rd Nov., 1899-Accepted, 9th Dec., 1899
COMPLETE SPECIFICATION.
A New or Improved Method of and Means for Blasting Rocks
and the like.
I, GEORG PHILIPP SCHNEIDER, of 56, am Thalberg, Bübingen, in the Empire of
Germany, Quarry Owner, do hereby declare the nature of this invention, and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
In the blasting of rocks, the forming of the blasting holes, by means of the
customary punch borers, produces so-called rifles," that is to say, channels
running spirally along the entire length, to the bottom of the blast-hole. These
so-called rifles" impart a whirling motion to the gases, at the point of explosion,
the consequence of which is that it is absolutely impossible for the bursting to
be regular.
These defects can only be obviated if a certain direction is given to the gases,
during expansion, and if the blast-holes are so made that the formation of "rifles"
is avoided under any circumstances.
In the process forming the subject of the present invention, this object is
attained by having the blast holes made by means of a crown-borer, so that it is
impossible for spiral grooves to be formed, and then providing the separate blast-
holes with longitudinal channels in the direction in which the rock is required
to burst, so that the direction in which the gases are to take in the blasting, is
clearly indicated.
A smooth fracture, actually progressing in the direction of the channels, is
thus obtained, as has been proved by numerous actual tests.
For the purpose of producing the longitudinal channels in the blast-holes, the
most appropriate appliance to be used is a borer-shaped shaft or handle corres-
ponding to the diameter of the blast-holes, and provided with diametrically placed
saw-blades, between which is disposed a spring.
In the annexed drawing, Figure 1 indicates in outline, a suitable manner of
arranging the channels in the blast holes; and Figure 2 shews the appliance for
making the channels.
If it is desired to blast off a portion of rock indicated by a¹, the bore
holes 61, 62, 63, etcetera, are placed in a straight line, whilst the bore hole c, for
instance, for blasting off obliquely, is on a line forming an angle with the
direction of the outer bore holes. Each blast hole is now provided with two
channels k placed diametrically opposite to each other, and as these channels are
in the longitudinal direction of the blast-hole, they give the gases the desired
direction. Trials have shewn that the depth of these channels need not exceed
two to three millimetres.
In the case of a blast-hole as b¹, several channels should be provided, some-
what as indicated in the drawing, on account of the change of direction.
It is obvious that it is not only practicable to blast off rocks in quarries, or in
mines, but also to divide rocks which have already been blasted off; which,

page_text: hitherto, has had to be done by sawing, or by striking in a vertical direction, or
by splitting in a horizontal direction, in the natural position of the stone.
The most suitable appliance for making the channels in the blast-holes is the
one represented in Figure 2, consisting of a borer-shaped handle p, on the lower
part of which there are two saw blades z, movable about a hinge a. These saw
blades are kept apart by means of a spring c, they may converge slightly towards
the bottom, so as to facilitate their being introduced into the blast-hole. By
moving the handle p up and down in the blast-hole, the channels are sawn into
the sides of same.
"
The whole process; moreover, does away with the preliminary operation, which
hitherto, in the case of difficult blastings, has had to be attained by preliminary
blasting, and which may here be entirely omitted, as the channels which would
be formed by the preliminary blasting, are already in existence.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
"
1. In blasting rocks and the like, the process for determining the direction of
bursting, characterized by the blast holes, formed by means of a crown-borer,
whereby so-called "rifles" are entirely avoided, and provided with longitudinal
channels, running in the line of breakage, for the purpose of inducing the gases
which are developed at the explosion, to act in the desired line of breakage, by
means of said channels; substantially as described.
2. In blasting rocks, and the like, as characterized by Claim 1, an appliance for
making the longitudinal channels, comprising a borer-shaped handle p, corre-
sponding to the diameter of the blast holes, and provided with two saw blades z
placed diametrically opposite to each other, and a spring disposed within same;
substantially as described.