PLAN

Drilling Method No. 4: 8 drills on 4 columns used in heading.Bench taken off in one lift. Bottom taken up with lift holes.
Per RoundPer Cubic YardPer linear Foot of Tunnel
Total Depth DrilledNo. of Cubic YardsPounds of DynamiteAdv.Linear Feet DrilledPounds of DynamiteCu. Yd.Linear Feet DrilledPounds of Dynamite
Heading310-32063-71215-2578-94.5-5.13.4-5.77.935.6-45.26.9-45.0
Bench190-21089-100107-1558-91.9-2.21.2-1.711.121.1-24.13.3-18.9
Total1956.7-69.40.2-63.9
Per cubic yard, whole tunnel section3.-3.62.1-3.4
Blasting Notes:

All holes of whole round are cleaned and loaded before blasting isstarted

Number of Sticks
First Round:

5-6 lift holes, 7 to 9 sticks each

35 to 54

First row, sub-bench, 6 holes, 6 to 8 sticks each

36 to 48
Second Round:

Second row, sub-bench and widening holes, 8 to 10 holes,6 to 8 sticks each

48 to 64
Stub holes10 to 20

Bench: Total Sticks

129 to 186
Total Pounds107 to 155
Third Round:

8 cut holes, 7 sticks each, often requires 3 to 4charges

112 to 224
Fourth Round:

8 holes, First side round, 5 to 7 sticks each

40 to 56
Fifth Round:

8 holes, Second side round, 5 to 7 sticks each

40 to 56

2 dry holes 5 to 7 sticks each

10 to 14
Sixth Round:

4 to 6 widening holes and dry holes, 6 sticks each

36 to 48

Stub holes

20 to 30

Heading: Total Sticks

258 to 428
Total Pounds215 to 357

The average quantity of powder used on the whole work was about 2.9 lb. per cu. yd. The tables on the diagrams, Figs. 1, 2, 3, and 4, show that the quantity actually used in making the advance at the main working faces was about 2.5 lb. The difference is accounted for by the larger percentage of powder used for trimming the sides, breaking out the cross-passages between the tunnels, and the excavation of the ditches, the latter operation not being done until the concrete lining was about to be put in.

There was some time, too, during the earlier stages of the work, when it is believed that an excessive quantity of powder was used; for one or two months it ran up to 4 lb. per cu. yd.

[Fig. 5.]

MUCK CAR USED AT WEEHAWKEN SHAFT