Thanks for the response. My take FWIW is that it is important to...

Thanks for the response. My take FWIW is that it is important to note the language used when reporting the results of met testing. As you rightly suggest, metallurgy is a specialised field and open to misinterpretation by the layman. An obvious example is that when discussing the primary ore processing through flotation, the report refers to recoveries, as the grind size (in this case 53 microns) reflects a P80 particle size that could reasonably be expected through a conventional grinding circuit.

Alternatively the oxide testwork via leaching is much more of a blue-sky estimate indicating what could potentially be achieved. In this circumstance the report uses the word extraction in lieu of recovery, presumably as the tested P80 particle size (10microns JON1, 26microns JOS1) does not reflect an appropriate feed size that would be expected in most common, economically viable leach processes. In fact the most commonly encountered leach process - heap leaching, will involve no crushing/grinding at all and involves the treatment of run-of-mine ore with particle sizes in the 10s of mm.

This is where my question to you around the use of words like 'good' and 'excellent' come from. Generally preliminary test work into leaching of oxide samples will rarely answer the question of whether this method will be economically feasible, but will determine whether it is infeasible. This is why I believe the results can only reasonably be interpreted as 'bad/not-bad' rather than 'good' or 'otherwise'. In fact most heap leach processes will generally only see recoveries of around 50-60% in the absence of pre-treatment through a BIOX circuit etc, therefore Pd extraction of 76% at such a fine grind size may be cause for concern.Either way I eagerly await the results of further testing.

As always - DYOR and GLTA