Gold Mountain (ASX:GMN) is one step closer to starting resource definition drilling at its Down Under Rare Earths Project in eastern Brazil.
Assay test results from 359 samples, which were collected across 52 auger drill holes, show extra thick, shallow, and ‘high-grade’ rare earth mineralisation at the Capivara prospect within the project site.
Significant total rare earth oxide (TREO) intersections also reportedly contain high proportions of valuable magnet rare earth oxides (MREO). Peak MREO/TREO ratios are up to 60%, suggesting there is a strong magnet rare earth component within the mineralised system.
In addition to this, the saprolite zone and principal rare-earth accumulation horizon suggests a progressively decreasing chemical index of alteration (CIA) from about 97% at top of saprolite and about 60% at its base.
CIA values in the reported holes were mostly “very high” where TREO exceeds 400 parts per million. CIA ranged from 99% to 86%, which strongly suggests there is potentially deeper mineralisation, according to the company. More prospective saprolite-hosted zones could also extend to greater depths and lead to further drilling activity.
“Mineralisation has now been intersected across multiple drill sections, commonly commencing close to surface, with encouraging total rare earth oxide grades and favourable magnet rare earth oxide ratios that are consistent with characteristics typically associated with ionic adsorption clay style systems,” Gold Mountain executive director David Evans says.
The Australian Nuclear Science and Technology Organisation (ANSTO) is performing metallurgical test work for resource definition drilling at the northern end of Capivara. ANSTO is also testing samples for ammonium sulphate and magnesium sulphate leach to determine whether mineralisation is in ionic adsorption clay.
The process will be overseen and reviewed from Gold Mountain’s senior technical officers.
The company plans to secure environmental permits and apply for diamond-drilling to test deeper saprolite-hosted mineralisation. It will perform a comprehensive follow-up drilling program to test and define mineralisation.
Further auger assay results from Capivara South are also expected to be released from ALS Laboratories in the southeastern Brazilian city of Belo Horizonte.
Write to Richard Szabo at Mining.com.au
Images: Gold Mountain
