weight.] METHODS OF MINING. 29 
water is diverted into the flume, so that the large bowlders m ( dy be 
thrown out or broken up. Where the creek bed is wide this tempo- 
rary channel, continually eating its way downward, must be moved, 
step by step, from one side of the creek to the other, then perhaps 
back again in case the gravels are deep. In this way the mass of 
gravel is disintegrated and washed away and the gold is concentrated 
in a shallow deposit on bed rock. To clean up the bed rock, sluices 
are laid, beginning at the lowest point on the claim, and into these the 
enriched gravels are worked by means of wing dams and shoveling. 
As the work progresses upstream additional boxes are supplied. 
HYDRAULICKING. 
In the upper channels, as at the Woodin claim, the gravels have been 
attacked where the present canyon crosses the former stream bed. 
The gravel at the mouth was hydraulicked away and sluice boxes laid 
on bed rock, everything being worked into these sluice boxes by the 
powerful stream from the h} 7 draulic nozzle. The large bowlders are 
transported to the mouth of the channel by a trolley moving on a 
cable which extends the length of the workings (PL X, B). 
MINING BY ELEVATORS. 
Where there is insufficient fall in the creek, or where deep potholes 
occur which necessitate a lifting of the gravel, bucket elevators are 
used. A pit is first sunk to bed rock, into which a sump is excavated, 
and in this the wash collects, to be elevated to the sluice boxes above. 
When sufficient space is cleared a small sluice box placed in the bot- 
tom of the pit collects most of the coarse gold (Pis. VI, VII). 
SLUICE BOXES. 
The boxes used in the pits are usually 12 feet in length, tapering 
from a width of 18 inches at the upper end to 14 inches at the lower 
end, thus allowing them to fit into one another. The larger sluice 
boxes used above surface are 2 to 3 feet wide and from 50 to 100 feet 
long. 
Riffles of several sorts are in use. An ordinary form is made by 
fitting round blocks 4 inches thick, sawed from logs a foot or more in 
diameter, into the boxes. Another style consists of poles placed a 
half inch apart lengthwise in the bottom of the sluice box. Still a 
third sort is made of sawed strips of wood placed crosswise, and set at 
an angle with the bottom of the box, so as to overhang on the upstream 
side. It is customary to have two or three sets of the pole style at 
the head of the sluice, and below these the block riffles. All of the 
riffles are held in place by wedges of wood, so that they can be removed 
for the clean up, which begins with the uppermost set of riffles, the 
concentrates finally collecting on the lowest box. 
