The New York herald., 1872-10-21

The quantity of rock removed was s,29s cubic
yards.
OF machine drills-viz the Burleigh and diamond
drills; the former having drilled 90 100 1-l0 feet OF
aDa two boilers or air were se ana
suitable frame building erected over them. Air
pipes conveying the TO the tunnels and galleries
were laid; a new derrick and hOisting engine fOr
It's service were put up car tracks in the and
shaft, with turn table ut their point Of meeting,
the excavated rock to the dump-pie was con.
structed; two diamond drills have been purchased
and have been used, both Ia, as prospecting and as
son with the Burleigh drill they appeared at first
to be nearly equal in efficiency, but as the work
becoming more difticut, they showed inferior re-
Suits For prospecting, however, and for drilling
diamond drill cannot be dispensed with. 1t IS not
the Intention to condemn the diamond drill as
2 tunnelling machine, for it is highly probable
that in rock not 80 hard as that at Haett's Point it
would give excellent results The detailed survey OF
the rock has been made by Mr. William Preuss, sur
veyor and draughtsman assisted by Mr. +. Sylvester,
who have taken upon the reef more than sixteen
hundred soundings, each separately located, by in
struments from the shore. Great pains were
rock. 1t will be observed that seven OF
the tunnels are advanced to their full
rock has been perforated and scanned with excava-
tions renders the assurance OF successful result
scale OF progress OF these tunnels in comparison
with tnat OF tunnels driven on land is, oil course,
small, for the necessity OF precautions against the
heavy mass OF water above made 1t imperative to for
bid deep blast hOes large charges and firing by vol
leys With such restrictions rapid progress became
impossible 1t is to be regretted that the approprla
tion for the present year has been reducedto 2200
just one half Of the estimate. had hoped during
this year TO nave been able to take the preliminary
step Oin constructing the Golfer dam and sinking
the shaft towards the removal Of the gridir0n
which lies between the eastern and middle chan
nclS, and constitutes at once the most dangerous
reef IN Hell Gate, as well as the principal obstacle
to its uses as ship channel The removal of this
taneoasy with that Of lila Malietts @ Point. 1he doubt
OF success, however in the beginning, which gene
rally existed in the minds Of the community, proved
sufficient excuse Tor the limiting OF the operations
to Halletts Point. The case is now different; ex.
perience has proved that the process OF tunnening
can be successfully applied to the kind OF rock OF
which these reefs are composed no further delay
In enarging the scale OF operations should be per-
mitted.
STEAM DRILLING sCow AT DIAMOND REEF.
The number OF holes drilled and blasted was
seventy-six and of surface blasts forty-f0ur. The
was 7951a pounds. For the greater portion OF the
area OF this reef the rock is met with in detached
is covered With u 'e depos o
earthly matter. 1t Is therefore impossible to prose-
cute vigorously The work OF blasting, because the
hard pan removed and sOundings taken before a
position for the dome can be selected For these
reasons operations have been intermittent here
and directed with the view Of gradually obtaining
the desired depth. ~, 80 ::y,- -.
-,--.sL,-' cSENTIEs REEF.
TnlH reel mas Decn LnOrOuBnly ulasJcu, auu iS
supposed to need only few surface blasts to
further dslodge the portion scanned by blasts,
which will be lett after the grappe Is next re,
was ninety-three, and surface blasts seventeen.
The amount OF ntrO-glycerine consumed was 5,479
rocR se the useS Morris sS fe
Ings patent, and machines were hired OF
Morris Cummings and OF Mr. Shelbourne. The
grapplc Is very effective in moderate currents and
where the mass OF loose stone to be removed Is
deep; but where the currents are rapid and where
large the use Of the grapple is neither efficient
nor economical In the channel at He'll Gate the
grapple could not be used. Notwithstanding, 1t
Of time, to have owned graphing machine which
could have been applied at the time most
purchase could never be spared from the appro-
priation. AS i was, we were compelled to walt
upon the convenience OF those owning grapples
ness on hand. Owing to this we have moved
the steam drilling sc0w from reef to reef and
s' we have % been ~ able @ to secure the service Of
grapple. The amount OF stone removed
from Diamond and Cocnties reefs was 0,ll9 tons
While waiting for q grapple upon Diamond and
Coenties reefs IL was determined to remove the
steam drilling scow to He'll Gate and attack the
on Frying Pan FIRST. Fifteen holes were blasted
and the machine was moored TO Pot Rock After
few holes were drilled i was discovered that they
used exclusively since to remove the loose stone
the intention for the future to remove rock from
the bottom ID this way, to the virtual exclusion OF
the grapple. BY this means q reef can be tho
roughly cleaned Oft before leaving It. The current
IN the East River was thought during Springs to
be troublesome, but In Hell Gate 1t is simply ter
rible. The waters fairly run over the deck OF the
scow where the current impinges and in tho
well hole they rise above the dome to the level Of
the deck. In the East River there were required
2e,ooo pounds OF anchors, but In Hell Gate 5000
dome are just as satisfactory in Hell Gate as they
were in the East Hver-the swiftness OF the cur
rent in no way nterferes with Its working or sta.
bility. During springs in He'll Gate the current Is
estimated between nine and ten knots. Since tho
drilling machine has been mO0red over Pot Rock
II has suffered from four collisions, in every
case sending the colliding vessel to the bottom
without damage TO the scow Fortunately there
has been no loss Of life. On one OF these occur.
rences the c0idlng vessel passed under the scow
and carried or the dome with II. The dome was
shortly after recovered having lost fourteen out OF
nineteen OF the drilling tubes. Nothing but the over
hang OF the scow has hitherto saved 1t from being
sent TO the b0ttom-and 10 is quite evident that Q
vessel proof aganst ordinary collisions, is indls
pensablo to the work Of cleaning 0ut the 0bstruc.
lions in East River and He'll Gate. For the reasons
furnished In this report ask an appropriation OF
100000 TO be devoted to the completion Of the
tunnels and galleries ct Hallett'g Point, TO the
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