The playbook — rare earths · October 28, 2026
Spark fills in the Cruzeta rare-earth blanket with surface hits
Nine RC holes at the Arapaima project in Brazil land shallow rare earths, but they infill a known footprint rather than enlarge it.
Spark Energy Minerals reported results from nine reverse-circulation holes — eight at Cruzeta and one at a new target 11 km away — part of its Arapaima project in Minas Gerais, Brazil. The headline hole, ARA-RC-036, cut 52 metres grading 1,906 ppm total rare-earth oxides (TREO) starting right at surface — that’s roughly a kilogram of rare-earth oxide per tonne, with a richer 6-metre slice running 3,740 ppm inside it. Hole 035 hit 76 metres at 1,385 ppm, hole 037 ran 50 metres at 1,470 ppm, and hole 038 cut 26 metres at 1,579 ppm and ended still in mineralization. Four western Cruzeta holes (ARA-RC-039 to ARA-RC-042) returned shallower intervals of 14 to 22 m grading 760 to 1,338 ppm TREO. A ninth hole, 032, opened a separate area called Domingos Gonçalves 11 km from the nearest Cruzeta hole with 34 metres at 776 ppm.
This is a clay-hosted deposit — rare earths soaked into weathered clay sitting on top of granite, the kind of flat blanket that starts at zero depth and can be cheap to dig if the metal leaches out easily. The grades are modest next to hard-rock rare-earth mines, but they are broad, shallow, and strikingly consistent: all 36 holes drilled at Cruzeta so far have cleared the 500 ppm reporting threshold across a 4.4-by-1.5-km area. About a fifth of the rare earth here is the magnet-making kind, and a gallium layer sits above the rare-earth zone as a bonus. Spark is run by Dr. Fernando Tallarico, who founded Axel REE on the same Caladão Granite Trend before leaving that company in May 2025; none of his track record reaches full production. The stock fell about 25% over three months while the rare-earths peer index fell 17.7% — roughly seven points of extra drag, no reward from these results visible.
Now the caveats, and they are central. These are infill holes, sited 146 to 312 metres from their neighbours inside the existing footprint — they do not extend the target, and the company says continuity between holes has not been established. Every hole is vertical RC with down-hole lengths only; true widths are not known, though a flat-lying blanket means they may run close. The 500 ppm figure is a reporting threshold, not an economic cut-off. Most important: no metallurgical recovery has been demonstrated, which for clay-hosted rare earths decides everything — in-ground grade means little until the leach is proven. Neither qualified person — Dr. Tallarico nor VP Exploration Jonathan Victor Hill — is independent of the company. What to watch: planned metallurgical test work, RC holes at Boa Vista, and a USTDA-funded study still in negotiation — all stated as subject to financing, with scope and timing undetermined.