Lindfors

Prospect, Active

Commodities and mineralogy

Main commodities Au; Cu; Zn
Other commodities Pb; Sb
Ore minerals arsenopyrite; chalcopyrite; galena; pyrite; sphalerite; tetrahedrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale HE
Quadrangle map, 1:63,360-scale A-6
Latitude 63.208
Longitude -149.653
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Lindfors prospect is at an elevation of about 3,900 feet on the divide at the head of Bryn Mawr Creek. It is in the SE1/4 of sec. 4, T. 20 S., R. 11 W., of the Fairbanks Meridian. The location is accurate to within 500 feet. This is location 11 of Cobb (1978: OFR 78-1062).

Geologic setting

Geologic description

The Lindfors prospect lies at the head of Bryn Mawr Creek adjoining the Golden Zone claims. According to Ross (1933) no work had been done here for some time, but the prospect had been restaked in the summer of 1931. He reported development comprised a number of trenches and shallow ditches from which a very small amount of ground sluicing was done. Most of the trenches did not expose bedrock and were in frost-shattered material, largely rusty dioritic porphyry but including representatives of the clastic rocks of the vicinity. Capps (1919) noted that at the time of his visit in 1917 one open cut exposed a vein of massive arsenopyrite 4 to 20 inches thick on the contact of a decomposed dike and altered tuff. Another cut showed disseminated sulfides and veinlets containing sulfides, quartz, and a carbonate resembling ankerite, in calcareous strata. He reported that arsenopyrite, pyrite, chalcopyrite, and sphalerite were present there and that gold was reported in encouraging amounts.
The Lindfors prospect is about 1,500 feet south-southwest of the Golden Zone mine (HE043). The country rocks at the prospect are Permo-Triassic redbed sandstones, conglomerates, limestones and volcaniclastic sediments, which are intruded by Upper Cretaceous quartz diorite dikes. The deposit consists of quartz veins containing arsenopyrite, chalcopyrite, galena, pyrite, sphalerite, and tetrahedrite. Surface geochemistry values of 0.2 to 14 ppm gold, high silver, arsenic, lead, antimony and zinc have been reported (Hawley and Clark, 1974). The Lindfors deposit probably is a continuation of the deposit at the Golden Zone mine.
Geologic map unit (-149.655291395893, 63.2075257989475)
Mineral deposit model Polymetallic vein (Cox and Singer, 1986; model 22c)
Mineral deposit model number 22c
Age of mineralization Synchronous with the Golden Zone mineralization, dated as Late Cretaceous.
Alteration of deposit Quartz, sericite (?), and pyrite.

Production and reserves

Workings or exploration
Early development comprised a number of trenches and shallow ditches from which a very small amount of ground sluicing was done. Most of the trenches did not expose bedrock and were in frost-shattered material, largely rusty dioritic porphyry but including representatives of the clastic rocks of the vicinity. Capps (1919) noted that at the time of his visit in 1917 one open cut exposed a vein of massive arsenopyrite 4 to 20 inches thick on the contact of a decomposed dike and altered tuff. Another cut showed disseminated sulphides and veinlets containing sulphides, quartz, and a carbonate resembling ankerite, in calcareous strata. He reported that arsenopyrite, pyrite, chalcopyrite, and sphalerite were present there and that gold was reported in encouraging amounts.
One drill hole has explored the Lindfors zone at depth; there is a report of a shallow shaft, now collapsed, dug in the 1920s. Surface exploration consists of numerous pits and trenches. Close-spaced helicopter aeromagnetic and EM geophysical surveys have been flown over this prospect. In 1996, the State of Alaska flew a wider-spaced helicopter aeromagnetic survey that included this prospect (Burns, 1997).
Surface geochemistry values of 0.2 to 14 ppm gold, high silver, arsenic, lead, antimony and zinc have been reported (Hawley and Clark, 1974).
Indication of production None

References