The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1875-06-11
HARBOR IMPROVEMENTS.

BLASTING OPERATIONS AT coRNTIEs' REEF AND
HELL GATE.
General Newton yesterday, in company with
number or friends, including General Lowell. Gen
eral G. w. smith, Major Mclean and City Surveyor
smith, made tour OF inspection OF the different
harbor Improvement works now in progress The
party embarked on board the United States en-
gineers' steamer Geneva at Thirty-third street,
East River at noon, and proceeded TO tue rect OPP
poslte Coenties' slip, pier No. East River, where
some interesting blasting operations TOOK place,
the object being 10 remove heavy ledge OF rocks
which hitherto have been great obstruction and
danger to vessels drawing deep water.
DESCRIPTION OF THE REEF.
This reef lies about 500 ieet from the pierhead
and is nearly in the middle OF the river 1t Is
composed OF gneiss rock, with seams or quartz
vertically stratied and Is 300 feet long by about
100 feet wide, with twenty-sx feet curve. The
least depth oil water here in June, 1873 seven
teen feet, when operations were commenced by
drilling and blasting. This was continued until
December. 1873, when, on account of the lack Of
the necessary funds, operations had TO be sus-
pended. The minimum depth or water at this
time over the rock was found 10 be twenty-five
Ieet, showing that about ave feet o. the ledge had
been got out for the six months WORK.
THE PROGRESS MADE.
Since May 4, this year, when the work was re-
depth or the noes bored are rom six feet 10 If
teen feet each. Yesterday the fourteenth blast
was nred, consisting OF ten holes, varying IN
depth rom SIX eight leet or total OF sixty-nve
feet. The charges employed Tor blasting are oi
nitro-glycerine, placed IN conlcsl TN cans u an
and length answering 10 the ueptn 81 drill holes.
The fuses used are filled with illuminate Of mer-
curry and are ignted by lrictlonal and yoltaic cleo
Triclty The average advance CT the drill Is eigh-
teen inches per hour Tor nve-inch mole. During
the neap tides where the tidal current Is
least MANY as ulteeu IEGL nave
been drilled IN one tide. The charge Is eight
hounds OF nitro-ely cerIne per one foot OF hole.
Inc noles are from ak to eight feet apart. the
explosion OF the charges breaks the rock into con
yenient blocks Tor dreaglng. ways reel ut Hell
Ieet at mean low water, the greatest depth ever
reached, at a cost OF sis 80 per cubic ward, under
peeled 10 be removed TO a depth or twenty-five
feet al mean low water before the middle OF Au-
gust TINS year, when the anal removal OF Diamond
Reef. an obstruction 70 Navigation situated be-
tween Governors Island and the Battery, Will be
undertaken. Al present dredge Is employed TO
remove the debris OF previous blasts.
A VISIT TO HELL GATE
After witnessing the blast at Coenties Reef,
which was exploded under the direction OF Mr.. J.
II. Stuedlnger, the engineer IN charge, the party
PROCEEDED 10 He'll Gate and dlsembarked At Hell
iett's Point An inspection Of the works extend
ing under tue river Tor the purpose OF removing
the distractions was then had. General Newton
proposed TO do IN tne future the piers and the
roofs OF the different chambers have been reduced
some Of the drill holes Tor the nnal blast have
At Flood Rock q similar work Is commencing.
The shalt there has been sunk 10 depth Of ten
feet Already The nnal Olast TO do away with the
rocks outside Of Halletps Point Will be exploded
next spring, thus widening the present channel
ior snippng between Hogs Back and the As
toria shore 81 ABOUT $50 feet. The removal OF
Flood Rock, reel Of Dy far iarger dime nsions
tnan Halletts Point, win be completed. u -
hoped 10 about three years from the present
time. which Will widen the eastern channel 10
the westward cf Haletrs Point nearly 900 feet.
The party expressed Themselves alter inspect
ing the various WORKS, as highly pleased with
their experience.