Baker County Oregon Gold Production
The Sumpter district, between lat 44°37' and 44°48' N. and long 118°00' and 118° 18' W., is predominantly a placer district, but there has been a small gold production from quartz veins that cut argillite. Placer deposits were discovered here in 1862, and production was almost continuous until 1955.
Records of production before 1932 have not been found, but from 1932 through 1955 the district produced 129,004 ounces of placer gold and 2,206 ounces of lode gold. No production was reported from 1955 through 1959.
Terrace gravels along the Powder River and gravels in its tributary gulches, above the town of Sumpter, contain varying amounts of gold. Damming of the Powder River by lavas of the Columbia River Basalt resulted in thick accumulations of gold-bearing gravels in the Sumpter Valley (Lindgren, 1901, p. 655-656). As the river cut through the barrier, lower terraces were created, and these also were worked extensively.
UPPER BURNT RIVER DISTRICT
The Upper Burnt River district, which includes Bridgeport, Bull Run, Unity, and Hereford, is in southern Baker County, between lat 44° 15' and 44°36' N. and long 117°35' and 118°20' W. It is a large district and includes many localities that have produced small amounts of both placer and lode gold. Early production data are scant, but apparently some placers were worked before 1900. Total gold production through 1959 was about 9,300 ounces from all sources.
According to the Oregon Department of Geology and Mineral Industries (1939, p. 97-98), the eastern part of the district is predominantly argillite and contains some limestone and lava flows, and the western part is covered by more recent flows. Auriferous gravels along the Burnt River have been mined.
VIRTUE DISTRICT
The Virtue district is between lat 44°43' and 44°57' N. and long 117°22' and 117°45' W.
This is predominantly a lode district; placer operations consisted of small-scale diggings in some of the gulches below the veins. The Virtue mine, discovered in 1862, was one of the largest gold producers in eastern Oregon (Lindgren, 1901, p. 722). Other mines in the district that have produced significant quantities of gold are the Brazos, Flagstaff, Hidden Treasure, and White Swan. The latest production reported from the district was in 1956.
Early production of the district was about $2,500,000 in gold (about 121,000 ounces) ; about $2,200,000 came from the Virtue mine, which had its best years before 1900 (Gilluly, 1937, p. 73). Yearly production data for the district go back only to 1935. The total for the period 1935 through 1957 was 4,837 ounces from lode mines and 288 ounces from placers. Total gold production for the district through 1959 was about 126,000 ounces.
In the northern part of the district a strongly sheared diorite is the predominant country rock, whereas the southern part is underlain by argillite that strikes east-west (Lindgren, 1901, p. 721-722). Most of the more prominent veins strike northwest, and they occur in both the diorite and argillite. Gilluly (1937, p. 94) noted that the veins consist of quartz, calcite, scheelite, and a little sericite. Small amounts of native gold, pyrite, and chalcopyrite are present.