Arcadia Minerals has declared the Bitterwasser Lithium Clays and Brines Projects results untrustworthy after two laboratories delivered different assays from the same samples.
The Bitterwasser Project comprises four EPLs, 7614, 8101, 8102, and 8103, all held by Arcadia Minerals subsidiary Brines Mining Exploration Namibia.
The project is in the Hardap Region in the southern-central part of Namibia, approximately 190 km southeast of the capital, Windhoek.
The company drilled six holes over the brine anomaly at three sites for 567 metres, consisting of two holes per site during January 2024, using Hydrasleeve sampling bags.
Grab samples within the shallow holes were taken, and the results returned in February 2024 showed up to 84 ppm Li and indicated that grades were increasing in depth.
As the samples were taken as part of a grab sampling review, the samples were assayed by a single laboratory. This laboratory utilised MobiLab 130 Li Magnetic Resonance Technology, which several major lithium-brine producers and explorers use.
Samples were also assayed three times with minor variances, and the highest of the three values was reported. Observations drawn from the results announced in February 2024 were that meaningful mineralisation existed halfway down the basement and that mineralisation, as expected, increased to depth.
A detailed sampling program was subsequently undertaken using Hydrasleeves at 10-metre intervals to determine mineralisation in each hole down to basin depth.
Two accredited laboratories tested the samples for analyses with inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry technologies.
Arcadia Minerals says the assay results from the two laboratories showed significant material variances.
In addition to the material variances encountered, the observations drawn from the grab sampling were contradicted by the results received, as the overall tenor of mineralisation was significantly lower than what was previously reported utilising magnetic resonance technology.
Other elementary mineralisation appeared to remain constant, even to depth, under circumstances where the results previously showed the grade to increase concurrently as salinity increased to depth.
As a result, and mainly due to the variance of more than 200% in lithium content between the two laboratories, Arcadia Minerals declared the results untrustworthy.
The company says this significant variance in assay results is an essential challenge, making it impossible to determine how much the brines are mineralised.
Unfortunately, the inductively coupled plasma assay method utilised by the laboratories is known to give rise to spectral and physical interferences in some brine samples.
This may impact the accuracy of measurements. magnetic resonance technology, which was used to conduct testing from grab samples, is widely used in the lithium-brines industry to test grab samples.
The company will review its assay methodologies and possibly opt for an additional sampling method instead of relying only on the Hydrasleeve.
