Grant County Oregon Gold Production
The North Fork district includes the drainage area of the North Fork of the John Day River and Desolation Creek between lat 44°45' and 45°00' N. and long 118°15' and 118°55' W.
This is a placer district that dates back to the early 1860's. Pardee and Hewett (1914, p. 10) estimated the total minimum production to 1914 at $893,000 in gold (about 43,000 ounces) ; since then, only 1,336 ounces have been reported from the district. The principal mines were the French Diggings and the North Fork. At the French Diggings both moraine and stream gravels were mined, and at the North Fork a gold-bearing terminal moraine was mined (Parks and Swartley, 1916, p. 97, 164).
QUARTZBURG DISTRICT
The Quartzburg district is in eastern Grant County between lat 44°28' and 44°36' N. and long 118°35' and 118°47' W.
In 1862, placers at Dixie Creek were discovered, and shortly afterward lode mines were producing in the district. After the initial boom of placer mining, in which estimated production ranged from $600,000 to $6 million (Swartley, 1914, p. 198), the district slowed down to sporadic small-scale activity. Lindgren (1901, p. 710) stated the production from lode mines to 1900 did not exceed $100,000. From 1904 through 1959, the recorded gold production from the district was 954 ounces from lodes, 8,534 ounces from placers, and 624 ounces undif-ferentiated as to source. Total production through 1959, using the $600,000 figure for the early placer production, was about 45,100 ounces.
The dominant rocks exposed in the Quartzburg district (Gilluly and others, 1933, p. 86-88) are metaandesite, metadiabase, other volcanics, and small amounts of argillite, of possible Carboniferous age. Diorite, gabbro, and serpentine bodies and their associated porphyritic dikes cut the metavolcanics and sediments. A mid-Cretaceous series of more acid intrusives—quartz diorite and granodiorite—is exposed in the Dixie Creek valley and near the head of Ruby Creek. The Columbia River Basalt once covered the entire area, but it has been eroded from the mineralized area. Gold and small amounts of copper and cobalt occur in fissure veins in the pre-Tertiary rocks. These veins probably are related to the quartz diorite intrusions. Quartz, dolomite, and calcite compose the gangue, and pyrite, arsenopyrite, glaucodot, cobaltite, bismuth, bismuthinite, tetrahedrite, pyrrhotite, chalcopyrite, sphalerite, and galena are the chief metallic minerals. Much gold came from oxidized parts of these veins in the early days (Lindgren, 1901, p. 710).