purington.] PROSPECTING. 39 
Mr. Stephen Birch, in a letter, gives the cost of placer work on Dan 
Creek, Nizina district, Alaska, as follows: 
By ground sluicing through 20-inch flume: 6,803 cubic yards, $8,781.44, or $1,143 
per cubic yard. 
By use of 8-inch cotton pressure-hose and nozzle through 20-inch flume: 1,600 
cubic yards, $1,457, or $0.91 per cubic yard. 
By use of pick and shovel only, through 10-inch sluice box: 2,320 cubic yards, 
$5,100, or $1,875 per cubic yard. 
A 273-foot tunnel, 6 feet by 6 feet, timbered: $1,017, or $3,725 per running foot, or 
407 cubic yards of gravel removed, which costs $2.50 per cubic yard. 
While the cost given above may seem high, it is because of the fact that it includes 
the cost of the tools and material now on hand, which were necessary to remove 
this gravel. Now, if this work is continued on for a number of years, the deprecia- 
tion of the tools, etc., could by charged proportionately. These prices may not be a 
criterion for future operations in that country but were our first cost of operation, 
and any strangers going into that section of country would be apt to run up' their 
costs to these figures. 
PROSPECTING. 
Creek claims must be prospected by shafts, open cuts, or drill holes. 
Shafts are generally used and are most practicable for the Alaska miner. 
Open cuts are not practicable, except in very shallow ground. Drill- 
ing requires expensive equipment, the machines costing from $3,500 
to $4,000 delivered in Alaska. As a means of prospecting auriferous 
gravels drilling is very satisfactory, but it is generally employed only 
in deep gravel beds, where dredging is contemplated. a In such ground 
excess of water prohibits the sinking of shafts. The cost of drilling 
with a 6-inch core churn drill is $2.50 per foot in California, and the 
tests of the deep gravels of the coastal plain have shown it to be 
practically the same in the vicinity of Nome, on Seward Peninsula. 
The cost of drilling depends on the price of labor and fuel, and will 
probably be about $3.50 per foot in the interior of Alaska. Unless 
contractors are found already equipped to do the work, drilling is more 
expensive than sinking pits, the cost of which varies from $3 to $8 in 
Alaska placer fields. 
In the solidly frozen ground encountered in northern placers it is 
not necessary to sink the casing around the pipe as in ordinary drill- 
ing. In partly frozen ground, where the casing is necessary, much 
difficulty has been found in pulling it up. A driller of the churn type 
is shown in PL III, A (p. 40), mounted on a scow for prospecting 
the bed of Snake River, Seward Peninsula. b The results obtained by 
drilling when compared with actual tenor of the ground are variable. 
jln testing the bed of Solomon River the results were found to run 7 
_ _ . 
| a See a further description of prospecting by drill holes, by Mr. J. P. Hutchins, in the chapter on 
'.jjdredging, later in this report. 
&For description of drilling operations in testing placer ground see Knox, N. B., Dredging and 
valuing dredging ground at Oroville, California: Trans. Inst. Mining and Metallurgy, June 18, 1903. 
Ri^lso Smith and Stebbins, Gold dredging at Oroville: Eng. and Min. Jour., Dec. 8, 1904. 
