American Rare Earths Ltd (ASX:ARR) has completed sampling at La Paz Rare Earths Project in the US, which has demonstrated that host mineralisation extends beyond the previously established resource parameters.
The initial sampling program followed up on historical exploration on the property northeast of Phoenix, Arizona, prior to 2020.
There were 45 outcrop samples taken to the south and west of previously sampled areas, identifying those rock types which host higher grade rare earth elements (REEs) and scandium.
The samples have between 59 and 693 parts per million total REE and 14 of the samples contain more than 300ppm total REE (31%).
Scandium content ranges from 1.4 to 23.5ppm and is roughly proportional to REE content.
Results of the sampling in the primary rock types occurring on the property in ppm rounded.
Andesitic basalt rocks
Additional goals were to identify which rock types are associated with the rare earths and scandium and what - if any - the role of alteration and silicification had on the enrichment or depletion of rare earths and scandium values.
New rock types including a finely banded gneiss and an andesitic basalt were identified.
This is a new rock type for the area which has a significantly high REE content (539 parts per million).
Future work will need to examine this rock type in more detail to determine extent, nature of the occurrence (ie flow or intrusive), and its relationship to the other mineralised rock in the area.
Map showing the values of scandium 11 ppm or greater.
Trenching for bedrock sampling
Sampling concluded that the metamorphic rocks (Augen gneiss and banded gneiss) are the best host rocks for rare earths and scandium mineralisation.
Because of the extensive alluvial cover on much of the property, it was decided to trench these areas in order to expose bedrock for sampling and to gain a better understanding of the geology.
The trenching was completed in July 2020, with results to be presented in a separate report.