ILLINOIS RIVER DISTRICT
The Illinois River district is along the west boundary of Josephine County between lat 42°13' and 42°29' N. and long 123°38' and 124°05' W.
Placer mining was reported as early as 1852 in the gravels of Josephine Creek, a tributary of the Illinois River (Raymond, 1870, p. 217-218), but records of early production are so fragmentary that the early output from the district is uncertain (Wells and others, 1949, p. 21). Scattered data attribute 2,006 ounces to the district from 1904 to 1932 (U.S. Geological Survey, 1904-24; U.S. Bureau of Mines, 1925-32). From 1932 through 1959 the district produced 327 ounces of lode gold and 3,670 ounces of placer gold. Total recorded production through 1953 was 6,003 ounces, but the unrecorded early production must have been at least 5,000 to 10,000 ounces. There was no recorded production from 1954 through 1959.
The geology of the Illinois River district was described by Wells, Hotz, and Cater (1949, p. 2-21). The country rock is chiefly tuffs, agglomerates, and flows of the volcanic member of the Galice Formation of Jurassic age. These rocks strike northeast and dip fairly steeply to the southeast. Discontinuous bodies of serpentine and larger masses of peridotite are also present. An elongate mass of hornblende diorite occupies the northwestern part of the district and borders the serpentine and peridotite. Lode gold deposits are of two typesâ€”small tabular quartz bodies or pockets containing free gold and sulfides, and auriferous gossans from which the sulfides have been leached. Both occur in noncarbonaceous rocks of the Galice Formation at a considerable distance from the hornblende diorite. The most productive placers have been those along the Illinois River.
LOWER APPLEGATE DISTRICT
The Lower Applegate district is in southeastern Josephine County between lat 42°07' N. and long 123°15' and 123°36' W.
The recorded production of this district from 1904 through 1959 was only 4,180 ounces and does not warrant its inclusion in this report; however, as placers were mined along Williams Creek soon after 1852 and through the 1870's (Winchell, 1914b, p. 229), it seems logical to assume a total production of well over 10,000 ounces. Most of the production was from placers, but lode mines were discovered as early as 1860 (Winchell, 1914b, p. 229) and were active on a small scale until 1950. The major lode mines were the Humdinger, Oregon Bonanza, and Porcupine. The most productive placers were along Williams, Slate, and Oscar Creeks and Missouri Flat.
The Lower Applegate district is underlain by Triassic(?) greenstone that is intruded by diorite and serpentine. Galice sedimentary rocks of Jurassic age are exposed in the western part of the district. The gold deposits are in quartz veins in the greenstone, diorite, and sedimentary rocks. Shenon (1933a, p. 50-51) postulated that the ores are related to the acidic intrusives and were formed at shallow depths and at moderate temperatures. Quartz, calcite, pyrite, galena, arsenopyrite, and native gold are the vein constituents. Shenon (1933a, p. 50) noted apophyllite as gangue in the Humdinger mine.
The Waldo district is in southern Josephine County between lat 42°00' and 42°10' N. and long 123°30' and 123°50' W.
Placers have been the mainstay of this district; however, there are a few lode mines, and some gold is produced as a byproduct from some of the copper mines. Placers were discovered along Althouse Creek in 1853 (Shenon, 1933b, p. 178-179) and were developed mainly by a group of sailors who constructed a long ditch to carry sufficient water to work the placers. By 1901 production declined, but the district was rejuvenated shortly afterward when hydraulic mining enabled substantial economical production from lower grade gravels. The district was active until 1942, but from then until 1959 it was virtually idle. Shenon (1933b, p. 179) estimated a total minimum placer gold production of $4 million (about 194,000 ounces) up to 1932. From 1932 through 1959 the district produced 1,228 ounces from lode mines and 18,614 ounces from placers. Total production through 1959 was about 213,800 ounces. The principal placer mines were the Llano de Oro, Deep Gravel, and Platerica mines. The Queen of Bronze copper mine, whose total production was valued at more than $1,350,000, yielded ore containing from 0.04 to 0.44 percent gold and 5.16 to 16.33 percent copper (Shenon, 1933b, p. 163).
The geology of the Waldo district was described in considerable detail by Shenon (1933b, p. 148-161). Triassic metamorphosed conglomerate, limestone, chert, argillite, and sandstone crop out in a narrow band trending north-south through the central part of the district. The Galice Formation of Jurassic age underlies the southwest corner of the district, and conglomerate and sandstone of the Cretaceous Horsetown(?) Formation underlie much of the northwestern part. Patches of Tertiary conglomerate, which is gold bearing, occur along the East Fork of the Illinois River in the central part of the district. Quaternary gravels, among them the auriferous Llando de Oro Formation, fill the valley of the East Fork of the Illinois River and its tributary streams and gulches. Metabasalt, meta-gabbro, and serpentine underlie most of the southeastern part of the district. The serpentine is believed to be of Jurassic or Early Cretaceous age, but the age of the metagabbro and metabasalt is unknown. Near the greenstone-serpentine contacts copper sulfides were deposited as irregular lenses in fractures. These deposits are in both the greenstone and serpentine. Small irregular deposits of chromite in the serpentine also have been mined.
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