purington.] OPEN-CUT M1NIN(J. 79 
form of the washing frame, where they are dumped by hand into a 
hopper. The material passes through a trommel, and the oversize falls 
into a self-dumping carrier and is elevated to dump. The undersize 
passes over tables and through sluices, and the lines are also raised by 
steam, a scraper being employed to secure dumping ground. There 
are, therefore, four distinct elevations, viz, by the shovel, the gravel by 
the tram, the coarse tailings by the bucket, and the fines by the steam 
scraper. 
The pit in which the shovel works varies in depth from 20 to 24 
feet. The gravel lies beneath 3 feet of muck, is generally mixed with 
considerable sand, and extends to bed rock. The material is well 
rounded and contains very few stones (but 1 per cent) that are over 18 
inches in diameter. Considerable black sand is found in the clean-up. 
In spots the ground is frozen, necessitating the occasional use of steam 
points. Steam is conveyed across the cut in a covered steam pipe 
hung from a stretched cable. A schist bed rock, generally hard, is 
excavated for about 2 feet b}^ the shovel. 
The shovel weighs 35 tons and revolves 360 u upon a turntable. The 
dipper holds 1 cubic yard, and the machine has a capacity of 1,000 
yards in ten hours, though this can not be obtained owing to inadequate 
cramming facilities. Its cost on the ground is about double that 
charged by the manufacturer. The boom, when horizontal, reaches 
22 feet beyond the bow, but when at level of track only about 11 feet, 
rhree-quarter-inch cables are used in transmitting power. The faults 
)f cables in steam-shovel practice in inaccessible localities have been 
commented on above. The dipper contains no new features. Prongs 
ire added to save lip, the central one being longer than those adja- 
cent. The machine has 3 engines and uses in all about 10 horsepower. 
For conveying material three cars of 2 yards capacity each are used, 
mining on a 3-foot gage track with 16-pound rails. The cars are pushed 
>y hand to the foot of an incline, which has an angle of 22° and extends 
00 feet, and thence elevated by cable connected to a 40-horsepower 
oist. Two hundred and fifty cars are usually raised in ten hours. 
)n reaching the platform the cars are dumped by hand and returned 
-*y gravity to the foot of the incline. 
From the hopper into which the cars dump the gravel is fed into a 
evolving trommel 16 feet long and 3 feet in diameter supplied with 
w r orm upon the inner surface and punched with holes varying from 
ne-half to 1^ inches in size. The rate of feed is regulated by hand, 
gate being raised and lowered when necessary. Water is supplied 
> the trommel by a 6-inch longitudinal pipe. All oversize passes 
irectly over a sheet-iron chute into a square hopper, from which it 
lis by gravity into a self -dumping carrier and is elevated approxi- 
mately 40 feet upon a dump. A 10-horsepower winch does this duty, 
t he hopper is furnished with a heavy iron gate, raised by the steam 
