Hi
@Nodferatu
Sorry for the late reply to your previous question.
"Unable to produce, consistent, reproducible analytical results. It's open to interpretation. Could that mean they have only reported on the assays that have shown mineralisation and haven't reported the assays that haven't reported mineralisation successfully? I don't recall any recent assays reported that have produced zilch, only that the assays have not been consistent in recovery. I find that statement a little ambiguous or is it wholly a statement focused on the fact that essays have varied from .49 - 360g/t."
I'll answer that question in generality.
Under normal standardised laboratory assay methods a certain number of samples from a run of samples would be selected for repeat assaying to see how reproducible (consistent) the assay results are. These samples are called duplicates. The duplicates are normally taken from a small sub-sample that has been split off a larger sample that has been prepared for analysis (ie dried, crushed and ground down to a certain acceptable size).
Once the repeat (duplicate) assays are returned they can be compared. If there is a big difference in the assay results then that difference can either arise because of problems with the assay method or because the sample itself has some property that causes variability (irreproducibility). For example the gold might be coarse or nuggetty and not evenly distributed throughout the sub-sample, despite the best efforts of the laboratories preparation method to try and homogenize it.
To determine whether the variability arises from the assay method or the sample itself the laboratory routinely runs through standard samples.
The standard samples are bought by the laboratory and are certified to contain a specific amount of gold (or whatever other element is being assayed). The link below is one to a company that sells these standardised samples to assay laboratories. In the case of the products this particular company sells the certified reference materials are pulverised ores, in which the gold content is known to within .0001 ppm.
http://www.assaysupplies.com.au/world-class-gold-ore-certified-reference-materials-new-low-prices
By running these standards through with the stream of natural samples the laboratory can be sure that their own assay method is not creating the variability (irreproducibility). ie they would quickly see that their results weren't matching the known standard grade.
Blank samples are also routinely run through with the natural samples at the beginning of an assay run to make sure the lab is clean ie the crushing and grinding gear is not contaminating samples.
Crushing and grinding equipment is normally cleaned with what is known as a “quartz rinse” i.e. very clean quartz sand and blanks are composed of local non-mineralised rock.
It seems that BBX's metallurgical process, which is also their assay process does not have all these checks and balances in place.
In fact it would be impossible to create a standard in the case of this "ionic" form of mineralisation as nobody yet knows what it is. Once the type of mineralisation is known then in theory consistent samples containing a known amount of the mysterious mineralisation could be created and used as a standard for a special in house assay scheme. Blanks could currently be incorporated in BBX's "assay" scheme as they are just un-mineralised samples.
You see the question of reproducibility/irreproducibility in assays can't be answered until you know the source of the variation in your assay results and to do this you need standard certified samples to run through your assay method to rule out that it is actually not your assay method creating the source of the irreproducibility. In the case of the BBX assay method currently this realisation leads to a Catch-22 situation. Esh
For anyone interested you can read more about Blanks, Duplicates, Standards, Field Contamination, Field Security and Representative Samples here (all very important to a successful exploration project)
https://www.geologyforinvestors.com/qaqc-of-geochemical-data/
"Some waffle contains facts. Other waffle is just all biased supposition.'
