Has Heavy Rare Earths found another massive saprolite-hosted deposit in Duke?
Special Report: Heavy Rare Earths appears to have latched on to another potential saprolite-hosted rare earths project, this time at Duke in the Northern Territory.
A little more than a month after unveiling an updated 159Mt @ 870ppm TREO inferred resource at its flagship Cowalinya project in WA, Heavy Rare Earths (ASX: HRE) has today confirmed the presence of highly anomalous rare earths at Duke following recent soil and historical drill chip sampling.
Duke is comprised of two adjacent granted exploration licences covering a total area of 255km2. Both are on the Phillip Creek pastoral lease, about 50km north-west of Tennant Creek and 25km west of the Stuart Highway.
Exploration on and around HRE’s tenement package previously focused on ironstone-hosted copper-gold-bismuth and IOCG deposits. This is the first time it has been scouted for its rare earths potential.
HRE is deploying an exploration model at Duke for an unconformity-type rare earths deposit similar to what is hosted at Northern Minerals (ASX: NTU) Browns Range project in WA’s Kimberley region.
The recent 400x200m soil survey at Duke centred around thorium and uranium airborne radiometric anomalies identified by past explorers, including a previously reported area of quartz veining and elevated rare earths in surface samples.
Subsequent testing at LabWest Minerals Analysis in Perth revealed two parallel rare earth anomalies, with the largest extending 3.5km in a northwest-southeast direction. It is also contiguous with a zone of elevated rare earths in saprolite identified from drilling during the 1970s.
The new soil data also confirmed and extended a copper-bismuth-gold anomaly picked up by a previous explorer which extends over at least 5km of strike and remains open to the south. The highest values recorded were 196ppm copper, 56ppm bismuth and 3.9ppb gold.
Drill chips from four open-hole percussion holes drilled in the 1970s in the northern part of HRE’s soil survey area were also sampled at the Northern Territory Geological Survey core storage facility in Darwin, along with drill core from a historical diamond hole. Two of the four percussion holes returned thick intersections of anomalous rare earths and were also submitted for conventional assay at LabWest.
Assays returned a best intersection of 42m @ 770ppm TREO from 8m, although HRE noted some possible “smearing” of samples could have occurred during drilling and therefore would exaggerate the thickness of the mineralisation.
“Nevertheless, these results point to substantial thickness of REE mineralisation in saprolite which, whilst contiguous with, do not coincide with the best rare earth soil anomalies,” the company said.
While it remains early days for Duke, HRE is already confident that historic drilling has not tested the best rare earth soil anomalies.
Historical intersections next to the new major rare earths zone include 42m @ 770ppm TREO from 8m (including 6m @ 1,481ppm TREO from 12m) and 24m @ 805ppm TREO from 4m (including 6m @ 1,281ppm TREO from 12m).
HRE executive director Richard Brescianini said the company was encouraged by the initial results from Duke.
“Assay results presented today indicated significant potential for a large saprolite-hosted rare deposit at Duke, similar to our Cowalinya deposit in WA,” Brescianini said.
“Additionally, the high rare earth grades within fresh Warrego Granite may also represent a secondary target, analogous to newly-discovered mineralisation in the Sybella Batholith near Mount Isa in Queensland by Red Metal (ASX: RDM).”
This article was developed in collaboration with Heavy Rare Earths, a Stockhead advertiser at the time of publishing.
This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.