Baker County Oregon Gold Production
The Cracker Creek district is between lat 44°48' and 44°54' N. and long 118°03' and 118°17' W., north of Sumpter.
The most important lode in this district and in Oregon, the North Pole-Columbia, was discovered in 1887, and it produced about $9 million in gold (Oregon Dept. Geology and Mineral Industries, 1939, p. 34). From 1907 through 1959 a total of 189,389 ounces of gold was recorded from the district.
The country rock in the district is the Elkhorn Ridge Argillite, which probably is of Permian and Late Triassic age. Cutting this argillite is the North Pole-Columbia lode, a vein system that trends northwest to east and continues unbroken for a distance of 5 miles (Lindgren, 1901, p. 658). The vein material consists of quartz, arsenopyrite, pyrite, and some chalcopyrite. Most of the gold occurs in the fine arsenopyrite (Parks and Swartley, 1916, p. 61). Comb structure is common, and some of the earlier minerals are crushed and shattered indicating some movement along the fissure system during deposition.
EAGLE CREEK DISTRICT
The Eagle Creek district is between lat 44°49' and 45°05' N. and long 117°00' and 117°45'- W., in the southern end of the Wallowa Mountains. The boundaries of this district overlap those of the Cornucopia district, and rightly so, for the gold-bearing gravels of the Eagle Creek district were derived from the Cornucopia stock.
Mining began in this district in the early 1860's when placers along Eagle Creek were worked. Those along Paddy Creek were worked also, but most of the gold production was from lodes and some was a byproduct of copper ore. The Sanger mine, the largest producer in the district, yielded an estimated $l1/2 million in gold from auriferous quartz veins (Lindgren, 1901, p. 738). The total early production of the district was estimated at $1,687,400 (about 82,000 ounces) in gold (Lindgren, 1901, p. 738-739). Total recorded production from 1931 through 1951 was 5,782 ounces of lode gold and 69 ounces of placer gold; from 1952 through 1959, no production was recorded.
The country rock of the area is chiefly Triassic greenstone and limestone cut by granitic and diabasic dikes (Gilluly and others, 1933, p. 63). The veins contain pyrite, chalcopyrite, sphalerite, galena, and free gold in a gangue of quartz and some calcite.
GREENHORN DISTRICT
The Greenhorn district is between lat 44°33' and 44°44' N. and long 118°25' and 118°32' W. in Baker and Grant Counties.
Both silver and gold veins were mined in the district before 1910. The Bonanza, the chief mine, produced $1% million in gold before 1904; it operated only sporadically from 1904 through 1916 (Parks and Swartley, 1916, p. 39). After 1930 the bulk of production was from placers. The total gold production of the district through 1959 was 89,200 ounces from lodes and 10,382 ounces from placers.
The following summary of the geology of the district is taken from "Oregon Metal Mines Handbook" (Oregon Department of Geology and Mineral Industries, 1939, p. 52-53). The district, which is on the eastern lower slopes of Vinegar Hill, is underlain by greenstone, argillite, serpentine, and granodiorite, and is surrounded by younger lava flows of Tertiary age. The granodiorite was intruded into the greenstone and argillite, and the ore deposits probably were emplaced during the closing stages of the intrusion. The deposits in the Bonanza mine and its vicinity are in argillite; those near the town of Greenhorn are in greenstone. The ores contain mostly gold and silver, but varying amounts of copper and lead are locally present.
Placers near Winterville, Parkerville, and McNamee Gulch were successfully worked. The value of boulders of silicified Tempskya (Cretaceous) "fern wood" in Eocene (?) gravels exceeded the value of the gold (T. P. Thayer, written commun., 1962).