50 ALASKAN MINERAL RESOURCES IN 190; 
CHOLMONDELEY SOUND. 
The prospects which have been discovered in the vicinity of Cholmondeley Sound are tl 
present in an inert condition. Although developed more or less vigorously in former year I 
the Roundtree property. Friendship group, Lady of the Lake group, Gladstone, and othtij 
claims have received so little attention of late that they need not be considered hero. Coppe ' 
ore has been found in Cholmondeley Sound at the Argosy claim, on the south side of Wesi 
Ann. and at the Fowlkes group, on MillerCreek, a tributary to the sound, about 2\ mile^ 
from Chomly post-office. At the latter claim chalcopyrite ore occurs as a mineralized hand 11 
eel wide in a gneiss-schist bell which strikes east and west and dips 60° N. A crosscut turti 
nel95 feet long has been driven and the fool wall of the ore body reached. The surf act 
exposures are well marked and often show surficial alternation products of the sulpliidj 
ore. The assay values are reported to be of sufficient grade to encourage further do volopmenii 
NIBLACB ANCHORAGE. 
The Niblack Copper Company's mine has produced more copper the last year than any 
other camp in the dist rict. It occupies a favorable position at the head of Niblack Anchorage 
in Moiia Sound, and with adequate surface equipment should be able to extract ore at low 
cost . 
The ore bodies occur as mineralized portions of schisl hands in a complex consisting 
chiefly of greenstone schists with occasional belts of quartz-sericite schist and allied rock 
types. The formation strikes N. 60° W., with a dip of 60° 70° S\V., and is cut by several 
later diabase dikes. Folding and faulting frequently occur and have an important bearM 
on the extent and shape of the ore bodies. Detailed work on t hese si ruotural feat ures in the 
mine has shown that the irregular outline of the ore hoc lies is often the result of intersecting 
fault planes. The largesl ore body which has been discovered and from which most of the 
ore has been derived has been thus'cul off bya fault plane crossing the formation at an 
acute ;mgle. The ore body is about so feet long, 18 feet wide, and 20 feet high, with a pitch 
of 45° NE. The ore is essentially low-grade chalcopyrite, with small values in gold and 
silver. Pyrite occurs in great abundance and renders the ore suitable only for smelta 
treatment. Small veinlets of nearly pure chalcopyrite are associated with ferruginous 
quartz and constitute then the jasper ore of the miners. 
The developments at the mine consist of a shaft ISO feet deep and over 750 feet of drifts 
and crosscuts, a rock house, hoist . w harf, and necessary mine buildings and surface improve- 
ment-. 
The Wakefield group of claims lies about 2 miles northwest of Niblack, at an elevation of 
about I .(MM) feet , and can be reached by trail either from Niblack or the north shore of Moira 
Sound. The claims were located in 1904 and have not yet been thoroughly exploited. A 
shaft 50 feet deep has keen sunk and ;i short drift tunnel extended at that level on one of the 
claims. The ore is similar in every respect to that at Niblack and occurs under like condi- 
tions in the general formation of schists and argiilites. The mineralized schist hand is wide 
enough to warrant considerable development if the values prove sufficiently high to pay. 
The ore is a low-grade chalcopyrite-py lit e ore with small values in gold and silver. 
The properly has recently keen bonded by a large company, which plans to give it a 
thorough test the coming season. 
IIKTTA I.NI.KT. 
The mining interest- on the west const of Prince of Wales Island are confined to a small 
area in the vicinity of Copper Mountain to the east of Iletta Inlet and extending for several 
miles inland. To present the geologic relations encountered and to show the mine positions 
the accompanying sketch map has been prepared (fig. I). In the central portion of t ho 
area a wide intm-ive stock or boss of granite invades irregular masses of limestone and 
quartzite of uncertain age. The masses of limestone have keen so completely metamor- 
phosed to coarsely crystalline nialkle thai bedding planes are destroyd. The (pia it /.ites, 
