Adirondack magnetite-apatite deposits

Region East, Northeast
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Favorable geologic units (specific granites or likely granites under cover), geophysical anomalies, known occurrences and mines. The magnetite deposits of the Adirondack Mountains can be considered a major potential source of fluorine, mostly as a coproduct or byproduct of iron mining. The potential tonnage of fluorspar in magnetite deposits may exceed a million tons.
Identified resources Historical production of iron and titanium (ilmenite).
Production Unknown.
Status Past mining.
Estimated resources Unknown.
Geologic maps Rickard and others (1970), scale 1:250,000 [Adirondack sheet]; Horton and others (2017), scale 1:500,000; (current NCGMP projects are mapping at 1:24,000 scale in collaboration with the New York State Geological Survey).
Geophysical data Variable aeromagnetic and aeroradiometric coverages; 60% Rank 4 and 40% Rank 1 (Shah, 2016).
Favorable rocks and structures Leucogranite (Lyon Mountain Granite Gneiss); granitic gneiss. Titanium-rich deposits occur in metagabbro and anorthosite and are included in other focus areas.
Deposits Mineville district (USMIN Site ID: NY00014), Mineville mines (MRDS dep_id: 10151463) (Adirondack Ore mines. Harmony Bed, Old Bed, New Bed, Upper Works Ore Body, Miller pit, 21-Joker Bonanza).
Evidence from mineral occurrences MRDS; USMIN; updated information in Valley and others (2011); Taylor and others (2019).
Geochemical evidence Limited response, mostly yttrium; see Taylor and others (2019).
Geophysical evidence Radiometric eTh highs where deposits not covered with glacial sediments. Magnetic anomalies.
Evidence from other sources Unknown.
Comments This is a known deposit area and past producer for Fe and Ti. Tailings and waste piles may contain significant resource, and are more likely to be used than in situ ore. Some of the area has been surveyed (Shah and others, 2021); geophysical data, especially magnetics, are very helpful for delineating deposits while radiometric data assist mapping alteration patterns and large tailings piles that contain REE. Recent and ongoing detailed mapping work has provided much insight. Existing project to support work (National Cooperative Geologic Mapping Program).
Cover thickness and description Cover less than 100 m, some exposed at surface.
Authors Gregory J. Walsh, Anjana K. Shah, Nora K. Foley.
New data needs Geologic mapping at 1:24,000 scale, airborne geophysics.
Geologic mapping and modeling needs Detailed mapping 1:24,000 scale.
Geophysical survey and modeling needs High resolution aeromagnetic and aeroradiometric data to delineate deposit and for framework geology.
Digital elevation data needs Lidar complete.