Gold Mountain Spots More Rare Earth Potential Beneath Capivara

Strong Intersections Leave Depth Question Open

Gold Mountain Limited (ASX:GMN) has produced some of its clearest rare earth results yet from the Capivara Prospect in Brazil, but the more consequential message may be what the auger program failed to reach. Several holes stopped within or near mineralised intervals, leaving much of the deeper saprolite profile untested.

The standout result was 12 metres at 1,283 parts per million TREO in hole CPAD260141, including 8 metres at 1,513 ppm TREO from 14 metres to 22 metres. That inner interval contained 638 ppm Magnet Rare Earth Oxides, or MREO, and 385.16 ppm neodymium-praseodymium oxide. Other notable results included 4 metres at 1,537 ppm TREO within a 7-metre interval in CPAD260158, and 5 metres at 874 ppm TREO in CPAD260156.

The reported zones also carry meaningful magnet rare earth content. MREO represented between about 38% and 42% of TREO in the principal intersections, while the broader results reached as high as 48% MREO/TREO in CPAD260157. Individual analyses in CPAD260141 returned NdPrO of up to 695.51 ppm, although these are exploration results from one-metre samples rather than a resource estimate.

Auger Limits Point to Diamond Drilling

The drilling was designed to provide broad areal coverage with handheld power augers, and ground hardness and duricrust restricted penetration in places. The holes were vertical and reached depths of up to 26 metres in the reported collar table, with true widths not established. CPAD260144, which reached 24 metres, did not produce a reported interval above the company’s 400 ppm TREO threshold but did encounter lower-grade halo mineralisation at depth.

Gold Mountain’s interpretation is that most drilling sampled the upper part of the saprolite, the weathered horizon the company identifies as the principal rare earth accumulation zone in the region. Chemical Index of Alteration values in reported intersections above 400 ppm TREO ranged from 99% to 84%; the company says progressively deeper saprolite, where CIA values may fall towards about 60%, remains largely untested.

That interpretation supports the next stage of work, but does not establish that grades or thicknesses will improve with depth. Diamond drilling is planned to test vertical continuity and the deeper saprolite profile, subject to environmental permitting and approvals. Additional auger infill drilling is also underway in areas where earlier holes achieved limited penetration, while further assay results remain pending.

Metallurgy Adds a Second Test

The geological story is being tested alongside the extraction story. Earlier ANSTO ammonium sulphate desorption work at pH 4 returned up to 65.9% extraction of TREY-Ce and up to 63.6% extraction of magnet rare earth elements from samples in CPAD250007. Results varied materially with depth: the uppermost tested interval produced less than 20% extractable TREY, while deeper samples delivered stronger extraction and low concentrations of deleterious elements in the leach solutions.

That variability matters because the current auger campaign has predominantly sampled the upper weathered profile. More Capivara samples are being submitted to ANSTO, and the pending work will help determine whether the promising extraction response is consistent across the prospect and down the profile. The filing also cautions that these auger samples are not intended for resource estimation without reanalysis, and that no standards, blanks or duplicates accompanied the samples.