Brine grades and testing

At the risk of introducing a pessimistic note . . .

Can anyone help clarify some questions about the synthetic brine benchtop testing ASN did (ann 12/04)?
That announcement mentioned a synthetic brine of 1700 ppm Li (lithium) only, with lithium loss of less than 3% in the magnesium reduction process.

Magnesium (Mg) is an "impurity" in lithium brines, and must be extracted. Previously it was not possible to remove the Mg without removing equal amounts of Li (or so I've heard). The Paradox Basin brines of ASN have very high Mg content (compared to, say, Clayton Valley in Nevada), with ca. 20,000-50,000 ppm Mg for mostly only a few 100 ppm Li.

There is more detail of the benchtop testing ("Phase 1 metallurgical test work") at the end of a lengthy "update" ann a few months later (06/07). This details the 1700 ppm and 500 ppm Li brines (synthetic) which were tested. Although it is stated again that "during the [Mg precipitation] process the lithium loss was less than 3%", the actual figures given in Table 3 don't seem to match this, and are far more discouraging.

For the 1700 ppm sample (1.7 g/l), the lithium loss after Mg and Ca removal was nearly 30 % (from 1.7 to 1.2).
For the 500 ppm sample (0.5 g/l), the lithium loss after Mg and Ca removal was over 50 % (from 0.5 to 0.23).

Am I missing something? Can anyone explain this?



ALSO, the 1700 ppm Li figure appears to be questionable anyway. It is cited a lot by ASN, as the reported grade from the 'White Cloud No.2' well, but is far higher than the 500 ppm from the 'Long Canyon No.1' well 100 metres away, and an August report from the TRU Group Inc suggests it is an error and should actually be 170 ppm (http://trugroup.com/downloads/tru-lithium-paradox-basin-error-release-2017-08-08.pdf ).

The main target brine aquifer for ASN in the Paradox Basin is about 1,800-2,000 metres deep (Clastic Zone 31). This is much deeper than a lot of targets in, e.g. Nevada (e.g. RLC's Columbus Salt Marsh project). If the grades aren't much better than elsewhere (e.g. Nevada)(if that 1700 ppm figure can't be believed), and Mg content is so high, and Mg-Ca extraction is likely to remove more than half the lithium anyway, the fundamentals of the Paradox Basin as a target start to look less robust.