New Orleans Republican. [volume] (New Orleans, La) 1867-1878, 1874-07-12
Blasting With Electricity.

| The following particulars of some sue.
cesstul blasting with electricity at Plump
| Hill quarry, near Mitcheldean, Gloucester
| shire, will prove interesting to many Of our
readers. This quarry is in an extremely
hard carboniferous limestone rock, and ia
worked for the production of lime. Blast
| ing operations ON an extensive scale have
been carried out there by means of gun.
| powder and dynamite, fred by common
| fuses. About twelve months ago a very
heavy charge of gunpowder was exploded,
which shook the rock considerably, and lett
! it in what is locally called "shelyed"
state. This explosion unfortunately caused
! the death of four men.
On the eighth instant Mr. Simmonds, the
proprietor OF the quarry, consulted Mr.. w.
Blanch Brain as to the feasibility of en-
| plOying electricity on the system devised
| by the latter gentleman for DrybroOk iron
mine, where it has been in beneficial use
for upward of twelve months. Mr. Brain
| at once proposed a practical test at the
quarry, and on the following day went
there and conducted the operation. Ga a
shelving" of the rock, close to its vertical
face, five holes, one and a half inches in
diameter, three to four feet deep and ii We to
six feet asunder, were bored and every
hole was charged with half pound Of
dynamite. Brains patent high tension
fuses were used, connected in circuit. A
snail ''dynamO-electrO mine explorer was
placed on the top of the cliff, and two in
sulated wires carried down the face of the
rock to the bore holes. All being ready.
two rapid turns of the handle of the ex-
ploder fired the five charges simultaneously,
and mass OF rock was detached twenty
eight feet long, and estimated to weigh
nearly 100 tons. The fracture was in the
line Of the five bore-holes, and there were
some lateral fractures as well, but the stone
was not smashed. The magnitude of the
result far exceeded what mad been ex.
pected; nevertheless. its most important
feature was the condition Of the mass of
stone, which clearly demonstrated that the
method OF blasting with small charges of
dynamite, fired simultaneously by cleo
tricity, is available in quaryiDg for build
ing purposes, as large blocks of stone can
thereby be dislodged without smashing
them.
The hardness and perfect safety of the
exploding apparatus Won approval from ali
engaged at the quarry. 1t is contained in
box thirteen by twelve and by six and
half inches, and weighs only tiftv three
pounds, so that it is readily carried from
one place to another in quarry az occasion
requires. No electricity is generated until
the moment it is wanted, when two turns
of the handle produced the desired effect.
The handle can be locked to the side of the
box by the man who has it in charge With
this apparatus, and Brains high tension
fuses, mistires never occur.
Plump Hill quarry, like many others, is
close to turnpike road, and when blasting
in the ordinary way elaborate precautions
with regard to traffic in both directions
have to be taken. By the use of electricity
this inconvenience to both workmen and
the public is almost entirely obviated. Mr..
Simmonds has determined to adopt blasting
by electricity henceforth, being fully salts
fed that it possessed great advantages in
safety, effectiveness and economy.