74 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263. 
A partly idle steam shovel, however, is not so serious a fault as idle 
men, since the shovel draws no pay. 
As to capacity, it is likely that a 2-yard shovel, fitted with extra 
long boom and li-yard dipper, will be found most economical. A 25- 
foot bank can be dug and caved. If the sluice and tramming capacity is 
700 cubic yards a day, the shovel will easily supply the material if no 
frost is encountered. 
PI. XI, A, shows one of the steam shovel plants in Alaska, oper- 
ating on Anvil Creek. The work done by this shovel is considered 
satisfactory, though its installation is experimental, and a larger one 
is planned. It supplanted a hydraulic-elevator system which was 
condemned. The 25-ton shovel (three-fourths-yard dipper) is working 
on an 18-foot face. It has not reached the bottom of the gravel, and 
must make another cut 7 feet lower vertically before all the pay is 
extracted. It is said that from July 23 to September 1, 1904, 25,000 
cars of li cubic yards capacity were dug and moved to the sluice 
boxes at a working cost of 12 cents a yard. The low bench is suffi- 
ciently above the level of the present creek to permit the pit to be 
150' incline at 10° ,:^^ r ' ZZ ^ „ , ,„ , . , -," ^ „' 
-* — "t — .,g mr — i Z l ^iiux ^ " — ^TnrijflljN sft Grade sluice 8 to/2 for I st 30. remainder 7 rt n </* 
^ .jgffSggQU"* 1 ^- MiiiiiiinnhYft u^jp ^COE First II boxes, iron riffles,— remainder \> 3j/' scraper 
a jBBB B ^n««' v/ '--''%->C3 Ct . $/ /5>V^aa, blank iron plates^ 
*-,>*<"' v^ Steam shovel £| /<& cable r 
■p W£$ 15 HR boiler 
*\H ^ and hoist 
Fig. 10. — Plan of steam-shovel operations, Anvil Creek. 
drained, the seepage water being handled by bed-rock drain. The 
workings were visited a. second time three weeks after the present cut 
was made. A complete section of the bank to bed rock is given below: 
Feet. 
Muck 3 
Fine gravel and sand 5 
Fine subangular gravel 5 
Large subangular schist and limestone fragments, stained with iron oxide, with 
a few bowlders up to 3 feet in diameter '. . 15 
The upper 3 feet of muck was ground-sluiced; the remainder was 
moved by the steam shovel. 
This frozen ground illustrates the peculiarly trying conditions with 
which the Alaska placer miner has frequently to deal. None of the 
ground encountered in 1904 was frozen. In the early part of the 
season of 1903, however, on account of the light snowfall during the 
preceding winter, the sides of a cut operated on were frozen to a depth 
of 8 feet and to a distance of 15 feet into the bank. This was annual 
