Little Falls transcript. [volume] (Little Falls, Morrison County, Minn.) 1876-1894, 1884-11-28
UNDER FLOOD ROCK
Preparations for What Will be the GrsRt.
est Explosion Known in History.

est Explosion Known in History.
New York Sun.-"There are four
miles of tunnels; in this mine" said
Foreman Bernard Boyle as he con.
Quoted visitor down into the excava-
lions under Flood Rock, which the
Government has undertaken to blow
up as it blewup Hallett's Reef, g short
distance above it in He'll Gate. "This
is all gneiss rock" the guide continued.
"Some of it is so soft that it can be cut
with a knife, and some Of it is SO hard
that it has to be blown up. The dip is
at an angle of about so deg. which favors
the entrance of water from the river
above u.s."
A dismal rein was pouring from the
rock and threatening to extiEguish the
oil lamp which the explorer carried.
On stepping through doorway he
found himself in water up to the knees
of his high rubber boots. In
the extreme northeast corner of the
mine a roar was heard, and soon the
water was seen rushing down through o
vide seam. A number OF laborers were
busily engaged in comenting and in
drilling test holes in new directions.
eve are, working carefully, now,
guarding against any further outbreak, "
said Mr.. Boyle. "There is q million
dollars worth Of work at stake here,
and we are exercising the greatest eau
ton. In case of sudden flood the mi
ners would escape through the door
there and close it. Then the compress
sed air Of this pipe would be let loose
and pressure of sixty pounds to the
square inch would prevent this section
from filling. The pumps are we'll able
to take care of the present leaks. We
might introduce the compressed all in
to the seams there aud stop it, no doubt,
but as we don't know the width of the
orifice further back, we prefer the
slower process of cementing."
when shall you be ready for the
great explosion?"
IN about one year from this month.
There are only ninety men engaged
here now, although we have had two
hundred or more in times past. Our
present force can complete the work by
The time we are ready for the explosion.
You would be surprised at the number
Of men who apply for work in such
mine. You see, we keep uniform
temperature here the year round, and
plenty Of good fresh air. Some of the
men have been here from the start, and
| we keep the old hands as long as posi-
BILE. No one las ever contracted the
| caisson disease here. The men are
| temperate and we never allow the use
Of liquor.
Next September you may see and
hear the largest explosion known to his
tory. All Of these holes you see there
with plugs in them will be filled with
explosives which will cost $36O,000
About 100, 900 cubic yards Of rock have
already been excavated. Whatever We
can carry out now will not have to be
6shed up by divers and grapplers in the
form of debris after the explosion
Men are busy here night and day. L
you desire to count, you will find abou
$50 900 two and three-inch holes drilled
for explosives already. The drills hav,
to be sharpened SO 900 times per year j,
the shops overhead. The rock, after be
ing mined, has to be hoisted, carried ava,
to deep water, and dumped. 4 hol
seventy feet deep, just north of Black
wells Island, has served largely as GU
dumping ground. The work require
drilling, blasting, hauling, hosting
dumping, pumping, timbering, trans
porting, surveying, sounding and man,
other things. Every hole has to b
drilled with mathematical precision t.
meet some other hole. We try to kee.
twenty feet and upward of rock for
roof, which requires an accurate knowl
edge of the depth of wafer above il
Ventilation is kept up bya fan lively
feet in diameter, driven by an engine
The large galleries ventilate themselves
The pumping operations are necessarl
continuous. The average inflow fror
leakage at low tide is 740 gallons pc
minute, but the last great leak, whic
you noticed few minutes ago, has IN
creased it ito over @ thousand gallons.