154 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263. 
two boxes have 4-foot .sides, reinforced inside and out with sheet iron, 
and are set high on a trestle to give the desired elevation for maintain- 
ing the dump. The grade is either or 1 inch in 12 feet for the head 
box, 2 inches for the second, 3 inches for the third, 4 inches for the 
fourth, and 5 inches for the succeeding boxes. It is proposed to sup- 
plant wooden sluice boxes on this claim with iron boxes 8 to 10 feet 
long and from 2 to 3 feet wide, of one-fourth-inch sheet iron, weighing 
from 500 to 600 pounds each and costing" from $15 to $20 in San Fran- 
cisco. Five hundred and twenty miner's inches of water are used 
for the elevator and 240 inches are used through the 3-inch nozzle of 
the giant. The water is distributed from the suppty pipe by 11-inch 
pipe to the two nozzles. By this arrangement 500 cubic yards of 
gravel can be handled in ten hours. It is said that the elevator is 
not handling over one-half the gravel that could be put through it 
if the larger amount could be moved to the throat. Experiments 
with scrapers operated by water power are in progress. 
The practice here is first to run back with a narrow cut 250 feet up 
the creek from the elevator throat, then to come forward toward the 
elevator, breaking- down the sides. 
If the cut is 150 feet wide, 250 feet long, and 25 feet deep, a new 
set-up must be made every thirty-four days, assuming that the plant 
is run all the time at its full capacity. To make the new set-up of 
boxes and to build the trestle requires $400 worth of lumber and the 
labor of 5 men for five days. In addition, it takes the whole crew of 
the placer one day to take the elevator from its old position and place 
it again. The total extra expense is, then, nearly $1,000 in money and 
at least one full day out of the short working season each time that 
the elevator is moved. 
In Seward Peninsula the handling of bowlders gives little trouble 
with the elevator. A 10-inch throat will take a 9f -inch bowlder. It 
is not uncommon to see the men near at hand throwing small stones 
down at the throat of the elevator. This is because stones are jammed 
in the throat. The elevator for the moment is not clearing the pit, 
and the small stones artificially fed will act as small cannon balls to 
break the obstruction. 
It should be noted that a very large amount of water is used for the 
elevator as compared with that used for the giant. It has been found 
most economical to distribute the water one-third to the giant and 
two-thirds to the elevator. If the elevator is too large for the water 
used, the employment of a choked nozzle or smaller nozzle will obviate 
the difficulty, while the larger throat does no harm. One of the most 
common difficulties with the hydraulic lift is the fact that it will choke 
if required to raise too much seepage or pipe water. 
Elevator practice in hydraulic mining has been so limited in its 
application, and has met with so little success, that definite rules for 
