AN IMPROVED METHOD OF EXCAVATING ROCKS AND OTHER HARD SUBSTANCES
Year: 1871

page_text: LETTERS PATENT to George Haseltine, of the Firm of Haseltine Lake,
& Co., Patent Agents, Southampton Buildings, London, for the In-
vention of "AN IMPROVED METHOD OF EXCAVATING ROCKS AND OTHER
HARD SUBSTANCES." - A. communication from abroad by Jacob
Shelley, of Mahanoy, and Milan C. Bullock, of Pottsville, both in
COMPLETE SPECIFICATION filed by the said George Haseltine at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 4th December 1871, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HASELTINE, of the Firm of Haseltine, Lake, & Co., Patent Agents, South-
ampton Buildings, London, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED
METHOD OF EXCAVATING ROCKS AND OTHER HARD SUBSTANCES," and have
petitioned Her Majesty to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that it has been communicated to me from abroad
by Jacob Shelley, of Mahanoy, and Milan C. Bullock, of Pottsville, both
in Pennsylvania, United States of America.

page_text: 1, at 1, me S
Lasting, to hereby declare
that the following Complete Specification, under my band and seal,
fully describes and ascertains the nature of the said Invention, and in
what manner the same is to be performed, in and by the following
statement:
The object of this Invention is to effect the removal of a large
quantity of material in a short time, and with a saving of labor and
expense, and I accomplish this object by first boring all the drill holes,
then filling them with suitable material, and then gradually shattering
the rock in successive lifts by repeated explosions, as herein-after
described, until it is torn away to the bottom of the drill holes.
+
The manner of practising this Invention is as follows:-I drill a
number of holes by means of diamond drills or other suitable apparatus
upon and within the circumference of the proposed excavation. These
holes are drilled to any required depth at which the boring tools can be
operated (it may be even many hundred feet), and the distance between
them, as well as their diameter, will generally vary with the quality of
the rock to be excavated. The holes are then filled with sand or with a
core of sand and clay, or with wood, or any other suitable material. In
sinking shafts it may be convenient to use water for this purpose. The
filling does not extend to the mouth of the holes, but a clear space is left
in each holo equal to the depth to which the rock can be torn away by
a single explosion. This depth will depend on the quality of the rock
and the quantity and character of the explosive substance used, but will
not in general be less than a foot and a half, or more than twelve feet.
A cartridge or charge of some explosive material is then inserted into
cach of the holes resting against the filling. The holes are tamped over
the charges in the usual manner, and the charges fired. The effect of
the explosion is to tear away the whole face of the rock about as far as
the depth to which the cartridges have been inserted, the filling behind
the cartridge taking the place of the solid rock in ordinary blasting to
receive the force of the explosion, and cause it to act outwardly, tearing
away the rock throughout the entire sectional area of the excavation, and
all the way from the cartridges to the mouth of the holes, after which the
fragments are readily removed in the usual manner. The filling is then
removed by digging or pumped out with a sand pump, or otherwise
removed to leave a clear space of sufficient depth in each hole, as before
stated. Charges are again inserted and the operation repeated till the

page_text: In
excavation is complete, or until the bottom of the boring is reached.
the latter case the boring tools are then applied again, and the operation
proceeds as above described.
In sinking shafts if the perforations are filled with water a plug
should be inserted into each to float or support the cartridge and
prevent the dropping of any debris down into the hole, the holes are then
tamped over the charges with water, clay, sand, or other suitable material
in the usual manner.
After each explosion the plugs are removed and the water pumped
out to the depth to which the rock can be torn away by a single
explosion. The plugs are then inserted again, the holes charged
and tamped, the charges fired, and the operation repeated, as above
described. By means of this process a great saving of time and labor is
effected.
The method of excavation hitherto practised requires the drilling
machinery to be removed to a safe distance before each blast, and after
the blast to be again adjusted for each separate hole. Much time is
consumed in this manner, and the labor required to effect the frequent
shifting of the machinery forms a heavy item of expense, all of which is
saved by my improvements.
Having thus fully described the said Invention as communicated to
me by my foreign correspondents, and shown how the same may be
conveniently and advantageously carried into practice, I claim, the
above-described method of excavating rocks and other hard substances
by first boring all the drill holes to the depth required, or as far as they
can conveniently be bored, filling them with suitable material, making a
space for charging and tamping between the filling and the face of the
rock, and shattering the rock in successive lifts by repeated explosions.
In witness whereof, I, the said George Haseltine, have hereunto set
my hand and seal, this Fourth day of December, in the year of
our Lord One thousand eight hundred and seventy-one.
Witness,
EDWARD C. JACKSON.
GEORGE HASELTINE. (L.S.)