The junior explorer has delivered a 560% in inferred lithium resources at Bitterwasser to 85.2 million tonnes grading 633 parts per million, for 430% more contained metal at 286,909t of lithium carbonate equivalent.
In response, the stock, which has traded at 13-33c over the past year, shot up 131% at open this morning to 45c, valuing it at around $38 million.
CEO Philip le Roux said the project was now comparable to a hard rock resource of 11.6Mt at 1% lithium.
Based on its recent cyclone metallurgical tests, it should be able to recover a concentrate of 59.6 million tonnes at 817ppm for 259,231t LCE from the resource.
Further, recent leach tests using an organic acid delivered recoveries of 82%, outperforming sulphuric acid and suggesting the project is amenable to environmentally friendly and low-cost lixiviants.
Bench-scale work is ongoing with the University of Stellenbosch in producing a lithium carbonate suitable for battery use.
The Bitterwasser orebody starts at surface and has been drilled to 12m, but remains open at depth.
It is also contained within the Eden Pan, one of just 14 exposed claypans, and le Roux said there may be more pans beneath the Kalahari Dunes - or the system may be one large pan.
Arcadia's work has also suggested the 4000sq.km Bitterwasser Basin has potential to host lithium-bearing brines, which remain an untested target.
Work has confirmed a conducive anomaly underlying the clays.
Similarly, the potassium and boron potential at the Eden Pan remains unassessed.
Arcadia, which controls the whole basin, suggested it is similar to the rich Clayton Valley in Nevada, USA.
Arcadia's near-term plans include four diamonds holes to enhance its understanding of the Eden Pan, and reconnaissance drilling of 2-3 holes on seven additional pans.
The company, which raised A$6.4 million at 20c in June 2021, has around $2.8 million cash at the start of July.