Yukon Region Alaska Gold Production |
NABESNA DISTRICT
The Nabesna district is between lat 62° 10' and 62°30' N. and long 142°40' and 143°10' W.
Gold had been known in this district since 1899, but there was no significant production until 1931 when the first shipments were made from the Nabesna mine, the lone producer of the district. Credit for the discovery is given to a bear who exposed the moss-covered outcrop of the principal vein while digging out a gopher. The property was developed by C. F. Whithan, who formed the Nabesna Mining Co. in 1929 and began shipping ore in 1931 (Wayland, 1943, p. 176-177). By 1939, much of the vein was worked out and in 1940 production halted. Additional exploration and development work in the district apparently was unsuccessful for there has been no further production reported. In its brief history the Nabesna district produced about 63,300 ounces of gold, all from lodes.
The rocks in the vicinity of the mine consist of the Nabesna Limestone of Late Triassic age and basaltic lavas and shale of possible Permian age (Wayland, 1943, p. 177). A few small bodies of quartz diorite cut the limestone. The thick Wrangell Lava of Tertiary and Quaternary ages unconformably overlies these rocks. Moraine and fluvial sediments of Quaternary age are found in all the stream valleys.
The ore bodies are in contact-metamorphosed limestone near the largest of the quartz diorite in-trusives (Wayland, 1943, p. 183-191). Ore deposits are of three types: bodies of magnetite with pyrite, calcite, and some gold; veins and bodies of pyrrhotite with minor pyrite and gold; and gold-bearing pyrite veins in tactite or along intrusive contacts. The third type is the most important and has accounted for most of the production of the Nabesna mine.
RAMPART DISTRICT
The Rampart district, between lat 65°15' and 65°40' N. and long 149°40' and 150°40' W., joins the Hot Springs district on the north.
Gold was discovered in the gravels of Minook Creek and Hess River and their tributaries in 1882, but for the succeeding 10 years nothing was done to develop the placers. In the early 1890's more discoveries were made and finally in 1896 the first mining was done on Little Minook Creek (Hess, in Prindle and Hess, 1906, p. 26). Smith (1933, table facing p. 96), however, does not report any production until 1904. The district reached its peak of activity before 1910; after that time, production decreased, and in the 1950's only a few hundred ounces per year were mined. Total gold production through 1959 was 86,800 ounces from placers. There are no workable lode deposits in the district.
The geology of the district, as summarized by Mertie (1934, p. 172-173), is chiefly the same as that of the Hot Springs district. Consolidated sedimentary rocks—which range in age from pre-Ordovician to Tertiary and include sandstone, shale, conglomerate, chert, limestone, and coal-bearing rocks —compose the bulk of the bedrock. These are intruded locally by granite of Tertiary age. The major placers are along Minook Creek and its tributaries and along Quail Creek, one of the tributaries of Troublesome Creek.
Several prominent stream terraces containing low-grade gold deposits occur along the Minook Creek valley, but most production has come from gravels at present stream levels along Little Minook Creek (Mertie, 1934, p. 181).
