52 ALASKAN MTNEKAL RESOURCES IN 190(3. 
The gold production for 1906 will slightly exceed that for 1905. 
JUNEAU MINING DISTRICT." 
Those mines which were operated during the year in the Juneau 
district have, with hardly an exception, given satisfactory returns, 
though many of the new and extensive developments that were 
planned failed of accomplishment. Two large stamp mills, at the 
head of Gold Creek and on Nevada Creek, were built, and the capacity 
of some of the power plants and mills at present in operation wi 
increased. 
MINES of DOUGLAS ISLAM). 
Douglas Island, though small, has become widely known as the 
locality of the Tread well group of mines. The geologic features of 
the Treadwell deposits and the methods of mining employed have 
been discussed in detail by Spencer'' and by Kinzie. c 
At the Alaska-Tread well mine the shaft has now reached a depth of I 
1,500 feet, and from it the 1,450-foot level is being opened. Other 
developments have been confined to the 1,050-foot and 1,250-footi 
levels. There is apparently little change in the character and value 
of the ore with increasing depth. On the surface the Glory Hole, on 
open-pit workings, have reached the 330-foot level below the aditt 
tunnel, and the ore is being mined close up to the walls. The open— 
pit method of mining will not be carried below this level. Most of the' 
ore milled has come from the stopes <>n the 600-foot, 750-foot, 900- 
foot, and 1,050-foot levels. The annual report for the year ending- 
May 31, L906, states that a total of 888,411 tons of ore was milled 
during the year, yielding $1,902,455, or $1.07 per ton in bullion andl 
$1.07 per ton in concentrates. The mining and development expense 
was $0.84 per ton, and the cost of milling $0.15 per ton. For then 
shipping and treatment of concentrates $0.12 per ton is to be added, 
and this with minor expenses makes the total operating cost $1.19 per 
ton of ore milled. 
On the Seven Hundred Foot fraction operations were renewed this 
year and considerable ore was mined from the 660-foot level. On the* 1 
770- and 880-foot levels developments were advanced and some ore 
was mined. The lowest, or 990-foot, level was opened and the sample- 
returns were reported to be encouraging. 
The Mexican mine is now developing its 880-foot, 990-foot, and 
1,100-foot levels. The ore mined has been mainly from the 550-foot t! 
a As the detailed report by A. C Spencer on the Juneau gold belt (Bull. U. S. fieol. Survey No. 287) has 
recently been published, only brief mention will be made of the late improvements on the mines within 
this area. 
b Op. cit. 
c Kinzie, R. A., The Treadwell group of mines, Alaska: Trans. Am. Inst. Min. Eng., vol. 34, L9fl 
pp. 334-386. 
