THE PHILIPPINE 
JOURNAL OF SCIENCE 
A. CHEMICAL AND GEOLOGICAL SCIENCES 
AND THE INDUSTRIES 
VoL. VII AUGUST, 1912 No. 4 
THE BLACK SANDS OF PARACALE. 
By Paut R. FANNING and F. T. EDDINGFIELD. 
(From the Division of Mines, Bureau of Science, Manila, P. I.), 
In 1905 an investigation into the black sands of the Pacific 
slope was carried on by the United States Geological Survey.t 
The field covered by this investigation was so large that the eco- 
nomic possibilities presented by specific localities could not be 
discussed. After the publication of the article cited, various en- 
terprises were started for treating black sands, but many failed, 
due to the lack of specific information in regard to the deposit 
worked. 
The winning of gold from black sands presents a different 
problem*for practically every district where they are found on 
account of the variation in the content of free and of combined 
gold; the physical condition of the grains of gold; the relative 
_ quantities of coarse and fine gold, magnetite, pyrite, copper, and 
platinum; and the character and treatment of the deposit. 
Therefore, in this investigation the black sands of one locality 
were taken, in order to determine their special characteristics. 
The locality selected was the Paracale mineral district in Ambos 
Camarines, Luzon, the one district where gold dredges were 
operating in the Philippine Islands at the time the experiments 
were begun. It was in this district that the first dredge was 
installed and this is the only one where dredging has been prof- 
itably carried on. 
There are three areas in this district where paying placer de- 
posits have been discovered: (1) Maliguit River, (2) Paracale 
*Day, David T., and Richard, R. H., Bull. U. S. Geol. Sur. (1905), No. 
285. 
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