Deposit

Ray River

Ray River is a deposit with published resource estimates in Alaska, recorded in the USGS USMIN rare earth element occurrence database (ver. 4.0, June 2019).

Facts on this page last re-verified Aug 12, 2026 — the oldest verification date among its current claims. How we verify.

Location: Alaska, United States (65.986, -150.571 approx.)

Commodities: tin; rare earth elements; gold; niobium; titanium; tungsten; zirconium

Deposit model: alluvial placer Sn · unclassified

Geology

Concentrates contain minor amounts (1% to 5%) of REE minerals as monazite and xenotime. Monazite is at least four times as abundant as xenotime. (Barker (1991)) Cassiterite is most highly concentrated where alluvium has been most intensively reworked. Principal placers are present in alluvium of modern floodplains and in low fluvial terraces. Tin is also widespread but less concentrated in high-level terraces and is absent in the white-weathering gravels. (Barker (1991b))

Published resource estimates

As compiled by USGS USMIN from the cited studies. Resource classes follow the source; "approximate" flags values USMIN reports as approximations. These are not current company reserve statements.

Material	Class	Amount	Grade	Contained	As of	Reference
tin dioxide (SnO2)	Inferred	≈99,100,000 t	0.211111 kilograms per cubic meter	16,500 metric tons Sn	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.
rare-earth elements (REE)	Inferred	≈62,100,000 t	0.094611 kilograms per cubic meter	5,880 metric tons REE	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.
rare-earth elements (REE)	Inferred	≈99,100,000 t	0.095711 kilograms per cubic meter	9,490 metric tons REE	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.
tin dioxide (SnO2)	Inferred	≈62,100,000 t	0.209111 kilograms per cubic meter	10,200 metric tons Sn	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.
tin dioxide (SnO2)	Inferred	≈73,700,000 t	0.211111 kilograms per cubic meter	12,300 metric tons Sn	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.
rare-earth elements (REE)	Inferred	≈73,700,000 t	0.095611 kilograms per cubic meter	7,050 metric tons REE	Jan 1, 1991	Barker (1991), Page 53, Table 10 — Barker, J.C., 1991, Investigation of tin-rare earth element placers in the Ray River watershed: U.S. Bureau of Mines Open-File Report 34-91, 63 p.

Exploration and site history

History: Investigations of mineral resources in the Ray River and Ft. Hamlin Hills area has been conducted intermittently by the U.S. Bureau of Mines during the years 1975 through 1989. Initially the work was part of a broader Trans-Alaska pipeline corridor reconnaissance conducted at the time of excavations associated with pipeline construction. The region contains very poor bedrock exposure and little was known of the geology prior to the construction. (Barker (1991))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.

Sources

U.S. Geological Survey · published Jun 1, 2019 · retrieved Aug 12, 2026 · archive unavailable: Wayback snapshot 20260427015518 of the ScienceBase item exists but the archive service returned 503 on verification 2026-08-12; recheck on a weekly pass