purington.] DREDGING. 161 
22,000 volts before its conduit over No. 6 copper wire 3-phase system 
to the dredge transformer, where a step-down to 500 volts was made. 
The turbines have 21-inch intake and 30-inch discharge, and the gates 
weigh 2j tons each. The water is available from April 1 to November 
15. The power plant cost $50,000, not including an outlay of $10,000 
for a 5-mile pole line, 3 copper wires, and 20 telephone wires. 
The pole line was built by contract requiring that the poles should 
be 6 inches in diameter at top, 21 feet above and 5 feet below the 
ground, and that timber should be cut for a width of 10 feet, all at a 
cost of $2,250 for 7 miles. 
A general view of the dredge is shown in PI. XXVIII, A. The 
cost, installed on the ground, was $200,000. It is of the close-connected, 
3-foot bucket, single-lift type, arranged with trommel and pivoted 
sluice box, and tables carried on separate float. This type of dredge 
was considered necessary on account of the presence of coarse gold in 
the deposit. That by all dredging engineers the occurrence of coarse 
gold is not thought prohibitive of the use of the stacker dredge is appar- 
ent from Mr. Hutehins's remarks on this subject (see pp. 173-190). 
The arranging of the entire tail sluice to turn in an arc, operated 
by stern lines, permits the distribution of the dump. The system of 
digging is against a spud and not a headline. Operations had only 
begun when the dredge was visited; its estimated capacity is 2,500 
cubic yards in twenty-four hours, digging to an average depth of 11 
feet. The dredge is equipped with 5 motors, and a total of 200 horse- 
power is used. The total weight is 100 tons. 
The hull was built in a pit on the ground, of Vancouver fir, and 
afterwards floated in the pond shown. It has a draft, loaded, of 3^ feet, 
!and is 90 by 36 feet in dimensions. 
The winches are controlled by levers directly above in the pilot 
house on the starboard side of the upper deck. The 7 drums operate 
|ithe 1 side lines, main ladder line, and 2 spud lines. 
The digging ladder is 90 feet long, 3 feet wide and 2 feet deep in 
the center, and is braced by steel trusses. The tumblers are of pentag- 
onal form and of steel, with manganese steel plates riveted on, w T ith 
]8-inch shaft. There are 96 buckets that hold 3 cubic feet each, have 
[the shape shown in PI. XXVIII, B, and are equipped with manga- 
nese steel lips, pins, and bushings. As shown by PL XXVIII, A, a 
jbowlder weighing 1,500 pounds rode one of the buckets and was taken 
■off on the upper deck. The buckets will dig 40 feet in front of the 
bow, and a bank 8 feet above water can be handled. The rate of wear 
jjm bucket lips had not been determined. A nozzle is used to clean the 
buckets as they pass the upper tumbler. No save-all is used. The 
pprocket wheels and chain are of steel, the diameter of the upper- 
wheel being 10 feet. 
Bull. 263—05 11 
