130 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263, 
Table 9. — Doable-riveted sheet steel slip-joint hydraulic pipe. 
Diameter 
in inches. 
Thickness, 
U.S. gage. 
Thickness in 
fractions of 
an inch. 
Head, in 
feet, pipe 
will safely 
stand. 
Pressure in 
pounds per 
square inch 
due to head. 
Weight per 
foot in 
pounds. 
Price per ! 
foot, San 
Francisco, 
1904. 
6 
18 
i 
20 
480 
208 
3. 80 
$0. 23 
6 
16 
1 
16 
600 
260 
4. 85 
.25 
8 
16 
T6 
450 
195 
6.30 
.32 
8 
14 
A 
563 
244 
7.75 
.35 
11 
16 
i 
16 
325 
141 
8.50 
• 37| 
11 
14 
5 
6¥ 
408 
177 
10.50 
.44 
11 
12 
7 
64 
572 
248 
14.50 
.,60 
15 
18 
1 
20 
191 
83 
8.50 
.46 
L5 
16 
1 
T6 
240 
104 
10.75 
.50 
15 
14 
A 
300 
130 
13.00 
.55 
15 
12 
& 
420 
182 
19.00 
.85 
18 
10 
9 
6T 
450 
195 
30. 00 
1.50 
22 
16 
1 
16 
164 
71 
15. 75 
.70 
22 
12 
SH 
286 
124 
28.50 
1.20 
24 
16 
1 
150 
65 
18.00 
.80 
24 
14 
tl 
187 
81 
22. 00 
1.00 
30 
16 
tV 
120 
52 
21.00 
.90 
30 
14 
A 
150 
65 
27.00 
1.10 
Pipe-reducing sections, Y's, forks, and elbows, and the method of 
"nesting" pipe for shipment are illustrated by tig. 23 (p. 131). Sec- 
tions of pipe are put together, as above stated, by slipping, or by flange 
or lead joints. If it is advisable to reenforce a slip joint, the simple 
device shown in fig. 24 (p. 132), which can be made quickly in the 
•blacksmith shop, will be found useful. The sleeve, lugs, and key 
should be made of soft steel. 
The disadvantage of diverting water from a straight pipe line may 
be illustrated by the experience of one of the Alaska operators. It 
was found that diverting the water from an 18-inch plugged pipe 
by means of 6-inch Y branch gave an efficienc}^ of 2, while in using 
the same water through the direct 18-inch pipe choked to 6 inches the - 
efficiency was 3. 
In laying pipe from the pressure box to the claim the line should 
be started at the lower end and the joints slipped in down the slope. 
Various methods of "setting" the pipe are in use. The device shown j 
in fig. 25 is used by Mr. F. H. Brackett, of Atlin, British Columbia. It 
consists of a square block of timber 3 by 3 feet by 9 inches, faced with 
one-sixteenth inch steel plate, to which is bolted a disk-like wooden 
plug the diameter of the pipe inside. Two men batter the timber with 
