METHODS ANT) COSTS OF GRAVEL AND PLACER MINING IN 
ALASKA." 
By Chester Wells Purington. 
GENERAL STATEMENT OF ALASKAN CONDITIONS. 
Placer mining' is that form of mining in which the surficial detritus 
is washed for gold or other valuable minerals. When water under 
pressure is employed to break down the gravel, the term hydraulic 
mining is generally employed. There are deposits of detrital mate- 
rial containing gold which lie too deep to be profitably extracted 
by surface mining, and which must be worked by drifting beneath 
the overlying barren material. To the operations necessary to extract 
such auriferous material the term drift 'mining is applied. 
As nearly all mining in alluvial deposits comes under the head of 
gravel mining, that term has been adopted in the main for operations 
described in the report of which the following chapter is a summary. 
Occasionally, however, the precious mineral sought lies in a matrix 
of fine sand, or even entirely in the crevices of the bed rock on which 
the alluvial deposit rests. Obviously the term gravel mining does 
not cover the cases in which detrital gold is extracted from such 
matrices, and the general term placer 6 mining has been, therefore, 
added in the title of this report for want of a name which shall 
include all operations considered/ When in the subsequent matter 
«The figures given below are extracted from a forthcoming report on the " Methods and Costs of 
Gravel and Placer Mining in Alaska" (Bulletin No. 263). The data furnish as close approximations 
as the nature of the work permits. The cost of all supplies, rates of transportation, cost of labor, and 
description of water, timber, and fuel resources in all important parts of the Territory, as well as full 
descriptions of all the methods of mining employed, will be given in the final report. 
b Placer, according to a Spanish definition, is a place near the bank of a river where gold dust is 
found. 
Lindley on Mines, sec. 11'.), makes the following comments: 
"Dr. R. W. Raymond (Glossary of Mining and Metallurgical Terms, Trans. A. I. M. E., vol. ix, p. 
164) defines the word placer as a deposit of valuable mineral found in particles in alluvium or dilu- 
vium, or beds of streams. He adds to the definition the statement that, by the United States 
Statutes, all deposits not classed as veins or rock in place are considered placers. As was said by the 
Supreme Court of the United States (Reynolds v. Iron S. M. Co., 116 U. S., 687-695; 6 Sup. Ct. Rep., 
601), in distinguishing the two classes of deposits: 'Placer mines, though said by the statutes to 
include all other deposits of mineral matter, are those in which this mineral is generally found in 
the softer materials which cover the earth's surface, and not among the rocks beneath.' " It is evi- 
dent (hat the term placer mining as used in the present report covers a much more limited field than 
would be the case were the term placer used in its broad legal sense. 
cThe term alluvial mining, used in Australia, is not generally employed in the United States. 
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