52 ALASKAN MINERAL RESOURCES IN 1904. [bull. 259. 
on the Discovery claim, and through it both the creek gravels and the 
side-bench deposits are being sluiced. The former difficulty in han- 
dling large bowlders contained in the gravel wash is to a great degree 
lessened by the swift current in the bed-rock flume, which transports 
the greater part to points below the workings. At McKinley Creek 
operations were not continued the last season, and across the divide 
on Nugget Creek and on the Salmon River the proposed developments 
of last year were not accomplished, little work being done. 
Glacier Creek, 3 miles west of Porcupine Creek, though idle during 
the summer, will be opened up this winter during the months of low 
water. Excepting the annual assessment work and the staking of a few 
claims, little or nothing has been done farther north, on Bear Creek. 
Prospects are reported in the vicinity of Skagway, where there are 
tunnels and small shafts on many of the deposits. None of thjese have 
yet become gold producers and many have been abandoned. 
JUNEAU MINING DISTRICT. 
The Juneau mining district embodies that portion of the mainland 
from Cape Fanshaw, in Frederick Sound, to a point opposite Sullivan 
Island, in Lynn Canal, and includes Admiralty and Douglas islands. 
A detailed study of the geology and mines on Douglas Island and 
on the mainland from Berners Bay to Windham Bay was made in! 
1903 by Arthur C. Spencer. His report, including topographic and 
geologic maps of the area, is now in preparation and will soon be 
available for distribution. In view of the early publication of this 
report only a brief mention will be made of the late developments on 
these mainland deposits, while a short description of the coal and 
metalliferous deposits on Admiralty Island will be added. 
TKEADWELL GROUP. 
During the last year a large 3,500-foot hoist has been installed at 
the Treadwell mine to replace the small one at the main shaft, whiclj 
has now reached a depth of nearly 1,200 feet. At this depth the ore! 
body has proved to be of better grade than nearer the surface, and at 
the 900-foot level the included mass of slate in the central portion of 
the deposit has disappeared and the deposit has a continuous width 
of over 300 feet. During the year ending. May 31, 1904, the explora- 
tion and development work, including drifting, cross cutting, and shaft 
sinking, amounted to 9,372 feet. The ore milled amounted to 774,595 
tons and the ore reserves are estimated at 4,017,289 tons. The value 
of the ore mined averaged $2.44 per ton, while the total expenses of 
extraction amounted to only $1.37 per ton. 
At the Mexican and Read3^-Bullion mines, east of the Treadwell, 
the developments during 1904 showed but little change in the char- 
acter of the ore bodies. Statistics on the developments and production 
