232 
ECONOMIC GEOLOGY OF SILVERTON QUADRANGLE, [bull. 182. 
in unoxidized, relatively low-grade enargite and pyrite. In 1891 the 
property came into the possession of the American Belle Mines, Lim- 
ited, a London company, which operated the mines until 1897. The 
report of the Director of the Mint for 1891 credits the mine with 
a product of $14-5,721 in gold and silver only, with no returns 
for copper. Since the sale of ore for this year yielded the company 
in the neighborhood of $110,000, the foregoing output probably in- 
cludes both copper and lead. At this time, however, the lower-grade 
copper ores could not be handled, as the nearest point at which they 
could be smelted was Denver, 500 miles distant. It was not until 
1892 that these ores could be treated in the Standard Smelter, at 
Durango. 
Mr. S. F. Emmons visited the mine in 1886, and the following facts 
in this paragraph are taken from his unpublished notes. He found 
Fig. 20.— Sections through the National Belle mine, showing ore bodies stoped and natural ore 
caverns. 
that the mine had been opened very irregularly, chiefly by tunnels 
run into the knoll, with overhead stop.es. The ore chimney was 
irregular, containing oxidized ore ("sand sulphate"), with kaolin in 
seams and vugs. The ore was confined to the quartzitic rock, the 
porphyry adjoining it being impregnated with unoxidized fine pyrite, 
as in the Yankee Girl. It seemed to follow two general fracture 
planes running at right angles to the main direction of fracturing, 
viz, N. 10° W. He suggested that the copper sulphates had been 
leached out first, leaving the relatively insoluble lead salts and open 
spaces. Mr. Emmons did not visit the lower part of the mine, which 
he was informed produced a low-grade enargite carrying chalcopyrite. 
The caves characteristic of the upper workings were said not to occur 
in the lower workings. Schwarz, 1 in the paper already referred to, gives 
1 The ore deposits of Red Mountain, Ouray County, Colo.: Trans. Am. Inst. Min. Eng., Vol. 
X VIII, 1889-90. pp. 139-145. 
