South Dakota

Hard rock lithium in the USA

The Black Hills of South Dakota are famous for historic lithium mining dating back to 1898 when Li-bearing spodumene (contains up to 7% Li₂O), and amblygonite (contains up to 10% Li₂O) was first mined near the township of Custer.

IRIS controls the largest number of lithium claims in the Black Hills. Its South Dakota Project has a combined total land holding of approximately 42,287 acres across 2,056 lode claims and is comprised of the highly prospective and strategic.

  • Dewy Project;
  • Custer Project;
  • Helen Beryl Project; and
  • Ruby Project

which contain abundant outcropping LCT pegmatite swarms. These projects represent large areas of fertile lithium-cesium-tantalum (“LCT”)-pegmatites covering several historic lithium mines and numerous historical industrial mineral pegmatite mines.

South Dakota regional location map with IRIS Projects

The largest known lithium spodumene crystals in the world have been found in the Black Hills, measuring over 15m long and weighing up to 90 tons.