Quartz veins and stringers in shear zone cutting comminuted and kaolinized tonalite of the Late Cretaceous Willow Creek Pluton, a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. The main vein is as wide as 18 ft and is made up of quartz, gouge, and altered tonalite (Ray, 1954). Ore concentrated at intersections of main vein and smaller cross veins. The stringer veins are displaced and broken up into distinct blocks by major post-mineralization faults. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling (Ray, 1954). The wall rock has been intensely altered with ankerite, kaolinite, and secondary quartz (Ray, 1933). Metallic minerals include pyrite, arsenopyrite, tetrahedrite, galena, nagyagite, gold, and sparse scheelite (Ray, 1933).

An adit was driven 40 ft to vein and then 56 ft along vein in attempt to find the ore shoot exposed at surface (Capps, 1919). By 1920, the adit was driven 300 ft (Chapin, 1920). A mill was installed, and both mine and mill operated in 1922 (Brooks and Capps, 1924). The first gold from the mine was produced in 1922. The Fern Gold Mining Company milled its last ore in 1928. Explored by more than 4,000 ft of underground workings plus stopes on 2 levels by 1931 (Ray, 1933). Workings extended beneath a tunnel of the adjoining Talkeetna mine (ARDF number AN025), but do not connect. In 1931, Thomas McDougal leased the property and worked the mine as the Fern Gold Leasing Company (Stoll, 1997). Mining stopped in 1941 and McDougal gave up the lease in 1945. During the time from 1931 to 1941, two new levels of adits were driven with over 3,000 ft aggregate length. In 1945, A.G. Dodson obtained a lease for the property and operated the mine until his death in late 1950. A mill and cyanide plant were present on the property, however the mill was destroyed by fire in 1946. A new mill was completed in 1948.