purington.] SLUICES AND GOLD-SAVING APPLIANCES. 197 
separate from the main sluice, the following device, adapted from one 
used in Siberia, as described by Mr. E. D. Levat," may be adopted. 
Its capacity is given as 172 cubic yards per shift. The principle of 
the undercurrent is here introduced, but the discharge, of both coarse 
and line, is to the same heap. This contrivance uses no power, and 
the method of handling- accumulations of tailings will be more expen- 
sive than in plants already in use. Where the steam scraper is so 
generally employed, however, as in the Klondike for handling tail- 
ings, the innovation of the modified "kulibinka" here figured (fig. 
43) would not add over $1,000 to the expense of installation, while the 
efficiency in saving the values would be greatly increased. 
It has been shown that the Klondike sluice generally necessitates a 
man forking. The object of this forking is to take out the stones, 
from 6 to 18 inches in diameter, after their surface is washed. 
Mechanical devices for accomplishing this would be advantageous. 
Experience with gold dredges has proved that the revolving screen or 
trommel, inside of which play powerful jets of water, accomplishes 
this screening process most successfully. The trommel is, however, 
expensive, and its various parts and castings must be specially made 
at elaborately equipped works. Therefore it is worth while to con- 
sider whether simpler and cheaper devices will not accomplish nearly 
as good results for the Alaskan miner. 
A plant to accomplish good washing results with sticky clay and 
gravel, and which can be built of materials at hand, is shown in fig. 
11. This type of plant, founded on the idea of the Siberian pan, has 
a capacity of from 100 to 200 cubic yards in ten hours, and can be 
built in the winter months. Assuming that steam power is already at 
hand, it requires no outside material beyond the iron shoes and simple 
castings and the punched steel plate which forms the floor of the pan. 
Its operation will require 10 horsepower, and if the material is con- 
veyed to it by the self -dumping carrier, the services of two men are 
sufficient to take care of the tailings. The machine will not only 
break up and thoroughly wash clayey gravel, but with properly 
arranged tables below will save the bulk of the fine gold which has 
been set free from its matrix. The cost of a pan of the dimensions 
here figured will not exceed $2,000, including the tables and sluices. 
The device for automatically clearing the bottom of the pan of large 
stones is not used in Siberia, where hand labor is cheap enough to 
dispense with it, the large stones being periodical^ removed b} T the 
lifting of gates in the periphery of the pan. The amount of water 
used in such a machine does not exceed ordinarily 125 miner's inches. 
The drawing of this machine is made diagramatically, since the man- 
ner of its construction will depend on local conditions. A four-armed 
casting, keyed to the shaft and bolted to the horizontal timbers, is 
aLevat, E. D., L'Or en Sib6rie orientale, Paris, 1897. 
