The dynamite used was “Forcite.” At first, both 40% and 60% were used, the 60% generally only for blasting the cut in the headings; during the latter part of the work, however, the 60% was used exclusively.

The rock as a rule broke very well, and only a comparatively small quantity could not be handled by the shovels without being broken up further by block-holing. In the sandstone the quantity of powder per cubic yard was much more than for any of the trap.

In drilling the Central Shaft, a 6-hole cut was made approximately on the center line, east and west, the enlargement requiring about 18 more holes, which were generally about 6 ft. deep, the average advance being about 4 ft. per day of 24 hours.

[Fig. 6.]

NORTH TUNNEL
[larger view]

SOUTH TUNNEL
[larger view]

PROGRESS PROFILES OF NORTH AND SOUTH TUNNELS SHOWING MONTHLY EXCAVATION

The drills were run by steam until a depth of about 150 ft. had been reached, air from the plant at Hackensack being available after