Adirondack magnetite-apatite deposits

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.
Identified resources iron
Production Yes, iron mining operations closed in 1976.
Status Past producer (iron)
Estimated resources Unknown
Geologic maps Many decades-old to century-old maps and region covered at 1:62K or 1:250K only, current NCGMP project to map at 1:24K collaborative with New York State Geological Survey.
Geophysical data Inadequate aeromagnetic/aeroradiometric data over 60% of area; 40% of area covered in 2015: Mag 60% rank 4, 40% rank 1 (2015); aeroradiometric 60% rank 5; 40% rank 1 (2015).
Favorable rocks and structures Leucogranite (Lyon Mountain Granite Gneiss); granitic gneiss
Deposits Mineville Mines (Adirondack Ore Mines; Harmony Bed; Old Bed; New Bed; Upper Works Ore Body; Miller pit; 21-Joker Bonanza)
Evidence from mineral occurrences Numerous deposits listed in MRDS; see updated information in Valley and others (2011) and 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 None
Comments This is a known deposit area and past producer for Fe. Tailings and waste piles may contain significant resource, and are more likely to be used than in situ ore. 40% of area has been surveyed; geophysical data, especially magnetics are very helpful for delineating deposits while rad data assist mapping alteration patterns and large tailings piles that contain REEs. Recent detailed mapping work has provided much insight. Existing project to support work (National Cooperative Mapping Program).
Cover thickness and description Cover less than 100 m, some exposed at surface.
Authors Gregory J. Walsh, Anjana K. Shah
New data needs Geologic mapping at 1:24K. Airborne geophysics.
Geologic mapping and modeling needs Mapping assists locations of ore, favorable host rock and favorable structures
Geophysical survey and modeling needs Magnetic data to assist locations of deposits; radiometric data to assist mapping alteration patterns
Digital elevation data needs Much of area has been flown; Lidar assists locating tailing and waste piles.
Bibliographic references
Valley, P.M., Hanchar, J.M., and Whitehouse, M.J., 2011, New insights on the evolution of the Lyon Mountain Granite and associated Kiruna-type magnetite-apatite deposits, Adirondack Mountains, New York State: Geosphere v. 7, no. 2, p. 357–389.
McKeown, F.A., and Klemic, H., 1956, Rare-earth-bearing apatite at Mineville Essex County New York: U.S. Geophysical Survey Bulletin 1046-B, p. 9–23, accessed at
Taylor, R.D., Shah, A.K., Walsh, G.J., and Taylor, C.D., 2019, Geochemistry and geophysics of iron oxide-apatite deposits and associated waste piles with implications for potential rare earth element resources from ore and historic mine waste in the eastern Adirondack Highlands, New York, USA: Economic Geology, v. 114, no. 8, p. 1569–1598,