The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1925-11-24

@HROUGHOUT the centuries
quarrying of stone has been
done with hand tools, as 1t
sui is to some extent; but ma
chimes operated by steam and cleo
trio power are now common, espe-
cially in the United States. a
visitor to a modern quarry finds
"channeling' machines chugging
back and forth on their short tracks
enormous cranes and derricks swing
ing huge blocks from place to place,
and light railways laid here and
there on the rough quarry bed to
haul out the stone and carry off the
strippings and refuse.
Occasionally there is heard a
mighty explosion. followed by a
shower Of splintered rock, and al
ways the air is filled with the I'M
musical sound of thYdding drills and
heavy hammers welded by brawny
arms. Rectangular masses of stone
weighing many tons are loosened
from the mother rock, great cranes
swing them onto cars, and these are
carried to the stone mill. There
swinging gang saws, with diamond
tipped teeth and under the constant
drip of water, cut the stones into
slabs while lathes and planning ma.
chimes turn roughly fashioned pieces
into columns, cornices and lintels,
and give them the finish that the
architect calls for.
Two Kinds of Rocks
Rocks are divided into two kinds
-stratified and misunderstanding
to whether they occur in parallel
beds or have no distinct lines Of
cleavage. The stratified or sedimen-
tary rock which include marble and
other limestones, slate and sand
stone. are the more easily quarried.
Granite and other igneous rocks.
however. although not stratified.
have a natural jointing of which ad-
vantage is taken in quarrying. Much
skill is needed to know lust where
the rock will separate most easily.
The plug and feather" method of
quarrying is the one principally en-
ployed in working by hand. A row
of holes is drilled a few inches apart
along the line at which it is desired
to break the stone. In each hole are
placed two feathers pieces of
steel rounded on one side to fit the
curve of the hole, then a narrow
wedge called a plug" is driven be-
tween the feathers" BY striking
in succession all the plugs in the
row, the splitting force becomes
great enough to rupture the rock.
This method is often used also in
machine-worked quarries to separate
large blocks after they have been cut
vertically by the steam-driven "chan-
neling" machines. Explosives. placed
in holes drilled vertically in a row
then exploded simultaneously, are
commonly employed for detaching
large blocks of stone. High ex.
plosives. such as dynamite, are
often used when the rock is to be
crushed into fragments for road
work, concrete, etc.
Channeling Machine
The channeling machine which has
found its greatest use in the United
States is like a small locomotive
travelling back and forth upon a
short track which is pinned to the
solid rock. AS it travels it strikes
on one or both sides of the track
with sets of long chisels set at diff
ferent angles; these vibrate up and
down. cutting a channel about one
and one-half inches wide and four
to ten feet deep, parallel to the rails
on which the channeler moves. Since
the channeler makes only vertical
cuts. the rock must later be lifted
from its bed by blasting or the plug
and feather" method.
There are 1000 stone and marble
quarries distributed widely through
the United States. Eighty per cent
Of the building limestone of the