Prospects, Active

Alternative names

Falls and Diana

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb; Zn
Ore minerals chalcopyrite; pyrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale JU
Quadrangle map, 1:63,360-scale D-4
Latitude 58.837
Longitude -135.0408
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 550 feet, in the Johnson Creek drainage near the mouth of Snowslide Gulch. It is 2 miles northwest of Berners Bay and 1/3rd of a mile southeast of the Jualin Mine (JU044) in the NE1/4 section 15, T. 35 S., R. 62 E. of the Copper River Meridian. The location is accurate and marks the center of several workings associated with these prospects.

Geologic setting

Geologic description

Note: Beginning in the 1990s, this and other old mines and prospects in the vicinity were consolidated by Coeur-Alaska into a single property (Birak, 2006). They have carried out major new drilling and underground exploration that better defines the mineralization, largely blurs the geologic distinction among the old deposits, and extends the ore bodies greatly. They have developed a coherent modern interpretation of the mineralization as a single deposit which Coeur-Alaska intends to mine as a unit. This deposit is described separately in ARDF as the Jualin (Coeur-Alaska) deposit (JU262). For geologic reference purposes and for their historic value, the pre-Coeur-Alaska data for this and the other old mines and prospects that Coeur-Alaska consolidated are retained in ARDF.
There are several prospects at this site which is completely covered by colluvium. The area is underlain mainly by sheared and altered Jualin Diorite (Barnett and others, 1988). Workings at the Thomas prospect include a caved adit (Barnett and others, 1988). A sample of dump material had 0.1 part per million (ppm) gold (Redman and others, 1989). The Valentine prospect, located on the Falls and Diana claims, is 300 feet west of the Thomas prospect. Workings include 2 water-filled shafts and a 115-foot adit. The shafts were sunk on felsic (quartz-sericite) phyllite and chlorite phyllite near the contact with the Jualin Diorite. The adit exposes pyritic, quartz-chlorite phyllite. The phyllite hosts a 5-foot band of stratiform pyrite and chalcopyrite which has been traced 150 feet to the southeast. The band contains up to 15 percent chalcopyrite and is in a shear zone in phyllite near the contact with Jualin Diorite (Redman and others, 1989). U.S. Bureau of Mines samples contained up to 161.9 ppm gold, 89.1 ppm silver, and 5.1 percent copper (Redman and others, 1989).
Geologic map unit (-135.04261173591, 58.8366727525654)
Mineral deposit model Low-sulfide Au-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Hydrothermal muscovite from veins in the Jualin mine are 53.2 Ma to 55.5 Ma (Miller and others, 1994). This coincides with the 55 Ma age of the other mesothermal gold veins in the Juneau Gold Belt (Goldfarb and others, 1997).
Alteration of deposit Sericitic and chloritic.

Production and reserves

Workings or exploration The Thomas prospect include a caved adit. The Valentine prospect, located on the Falls and Diana claims, is 300 feet west of the Thomas prospect and its workings include 2 water-filled shafts and a 115-foot adit.
Indication of production None



Barnett, J.C., Hayden, T.J., Bair, D.K., and Croff, T.C., 1988, 1987 summary report, Jualin gold project, Berners Bay District: Unpublished report for International Curator Resources, Ltd., 75 p.
Birak, D.J., 2006, Kensington gold project: Unpublished Technical Report for Cour d'Alene Mines, 116 p. (posted on www/, April 20, 2006).
Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W, 1997, Gold deposits in metamorphic rocks in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 151-190.
Miller, L.D., Goldfarb, R.J., Gehrels, G,E., and Snee, L.W., 1994, Genetic links among fluid cycling, vein formation, regional deformation, and plutonism in the Juneau gold belt, southeastern Alaska: Geology, v. 22, p. 203-206
Miller, L.D., Goldfarb, R.J., Snee, L.W., Gent, C.A., and Kirkham, R.A., 1995, Structural geology, age, and mechanisms of gold vein formation at the Kensington and Jualin deposits, Berners Bay district, southeast Alaska: Economic Geology, v. 90, p. 343-368.
Reporters J.C. Barnett and L.D. Miller (Juneau, Alaska ); D.J. Grybeck (Port Ludlow, WA)
Last report date 6/5/2008