American Rare Earths Ltd’s (ASX:ARR) wholly-owned subsidiary Western Rare Earths (WRE) has released a JORC 2012-compliant 2020 Technical Report that confirms the potential of the La Paz Rare Earths and Scandium Project in the US state of Arizona.
The report identified that the project merits further exploration and metallurgical test-work and while it is of relatively low grade, there is substantial room for expansion through additional drilling.
It also states that the deposit benefits from uncomplicated mineralogy, lack of significant uranium and thorium, favourable preliminary test-work and nearby supportive infrastructure and location.
Additional geological data
The present database for La Paz comprises surface prospecting and geologic mapping, surface outcrop and trench sampling and analytical data for 195 shallow percussion drill holes.
Further exploration, mainly in the form of drilling, will provide additional geologic and analytical data that may confirm a conceptual model of REE enrichment associated with allanite derived from or within nearby alkalic intrusions.
Recovery method potential
A preliminary test of recovery methods has identified a combination gravity and magnetic separation process as a possible mineral processing method.
However, the company believes it is imperative that better quality samples in the form of core be drilled in select high-grade areas previously identified by the percussion drilling.
Additionally, scandium recovery needs to be investigated and groups at Perdu University and Penn State have been identified that may be available to do the scandium recovery test-work.
REE recoveries by these groups are also being investigated.
Geologic map of the La Paz property.
Core and metallurgical test-work
A limited 6-hole coring program has been proposed at an estimated cost of $390,000 including associated metallurgical test-work.
This drilling will concentrate on the higher grade zones already defined by previous drilling and is concluded as being necessary for acquiring better quality, competent rock material for metallurgical test-work.
This is expected to begin this month with initial metallurgical test-work to be completed afterward and continue into the first quarter of 2021.
Pending the results of this work, more advanced metallurgical studies should be implemented in 2021, on the recommendation of the Wood Group in Perth.
Resource expansion drilling
The report also recommended that a detailed REE/scandium resource expansion drilling program should be developed for 2021.
To maximise grade, relatively short (30 to 50-metre) step out reverse circulation (RC) drilling should be completed in areas previous drilled where values exceeded 300 parts per million TREE.
Scandium values tend to be high also in areas of high parts per million TREE so the drilling will also likely identify a scandium resource greater than 11 ppm.
A face sampling bit RC drilling program allows for greater control of what interval a sample is coming from plus the RC rig sample collection system can provide high quality non-contaminated samples.
Updated resource planned
In 2011 an indicated and inferred resource estimate was made based on the results of 195 drill holes and more than 100 surface samples at 128.2 million tonnes containing 95.4 million pounds of rare earths (REE).
After completion of the confirmation core drilling in November/December 2020, the REE resource will be updated with the new core data.
Additionally, the historic drill data combined with the new core information will be used to calculate a maiden scandium resource.
Once a resource base and REE recovery method for the deposit has been established the company will undertake a preliminary economic analysis in the second half of 2021.
Mine planning will also be addressed during this analysis but it is anticipated that due to the near-surface exposure of the REE mineralisation, an open cut mining scenario will be likely.