76 
GTCAVEL AND PLACER MINING IN ALASKA. 
[BULL. 2G3. 
twenty hours. It is estimated that this is less than one-half the amount 
that could be handled were the shovel digging loose gravel. As it 
now works, the shovel is digging only one-third the time. 
For moving up the cars within reach of the dipper as each one isj 
filled the device shown in fig. 12 is used. This was devised by Mr. 
W. S. Purington, and has been in successful use at this plant for five! 
years. The long cylinder, made with casting to attach to the shovel, I 
here shown on the near side, contains a piston of equal length, which! 
is supported on suspended track and wheel as it leaves the end of the 
cylinder. To the near end of the piston a cable passing over a sheave] 
is attached. The other end of the cable is hooked to the corner of 
the gravel car, steam is turned into the near end of the cylinder, and 
t Steam 
Body of steam shoi/et 
Steam 
fxhaust'f^- 
£ 
3-r Sheave 
14 feet — 
Trolley .Track 
= 1 
Fig. 12.— Pulling-up device for steam shovel. 
as the piston travels back toward the forward end of the shovel cajl 
the gravel car is hauled by the cable an equal distance, from 5 to I 
feet, as may be required. Steam is then turned into the cylinder, 
allowing the piston to return and the cable to free itself; the cable iji 
unhooked and pulled by the car man to the following car and hooked 
in readiness to pull it along. The amount of steam and the time con- 
sumed in the operation are so small as to be almost negligible. Ity 
passing the cable around the body of the shovel car over a second 
sheave the cars on the opposite side of the shovel can be moved, when 
the relative position of the shovel is reversed. 
Dipper chains are generally preferable to cables in placer opera- 
tions, as illustrated by the experience of the shovel dredge in Solomon 
