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23/08/17
00:31
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Originally posted by eshmun
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As much as it pains me I think Skol has picked out the most important piece of information.
"Despite extensive development work conducted in laboratories in Brazil, Australia and Canada BBX has been unable to produce consistent, reproducible analytical results from mineralised rock located on its Apui projects ."
At least they have finally come out and said it. They don't have a reliable assay technique .
As my many posts have tried to explain this will make it very difficult for them to produce a resource estimate as firstly without a reproducible assay technique you can't rely on the grades in your drill holes and if you are relying on bulk samples for down hole assaying and are only obtaining averages of grades over long intervals (as they have already been doing) you won't be able to resolve the distribution of the mineralisation down the hole to a small enough level to define ore boundaries for economic mine models. Unless they can produce a reliable assay it's going to make it very very difficult for them to progress this project in conventional ways. ie produce a JORC resource estimate, mine model or feasibility study.
Also the requirement for bulk sampling doesn't really make sense because in their description of the processing of the bulk samples taken from Três Estados and Ema they say.
"The 5kg sample for metallurgical test work was a split from a 150kg bulk sample which was crushed and ground in a ball mill to 70% -100# and split using a riffle splitter."
This suggests that they only need 5kg to run their metallurgical scheme so they could quite easily go around collecting 5kg rock chip samples and running the process on them individually. I think the limitation here is the cost, not anything to do with the size of the sample.
If you take the average diameter of the tool that goes on the end of an RC drill rig, of say somewhere between 4 and 6 inches you get a hole diameter of approximately 150mm, and if you use a mid-range density for a fresh **bro of 3t/m3 the weight of material from a 1m down hole interval will be 0.018m3 x 3t/m3 = 0.054t 0r 54kg.
There is nothing stopping them riffle splitting standard down hole intervals (say 3m to 5m) and splitting off 5kg for the metallurgical procedure.
The sad truth though, is that if a 5kg split from a 4m composite interval is unreliable, splitting 5kg off a large compost interval won't make it anymore reliable.
IMO they should stop all exploration until they have a reliable and reproducible method for assaying samples or else they are spending shareholder money on work that ultimately will be unusable.
As far as the description of the mineralisation goes, nothing has changed there since the early days. If they can see sulphides in the rock, do a petrographic examination and determine what the metals are. If your specialist can't identify them there should be microprobes that can determine the composition or put it in the Scanning Electron Microscope (SEM). We know they have access to a SEM because they have reported the results from SEM analysis before.
It seems they are hell bent on continuing to fly by the seat of their pants and pour shareholder money into trial mining and a pilot plant based on unreliable metallurgy, unreliable drill information and no idea of the type of mineralisation they are dealing with or how it got there.
Eshmun
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Lots of words but little grasp of the crucial aspects, like all of the detractors here. No idea. The extraction process is still in the developmental phase.
They are getting 360g/t from the rock but it's partial recovery method. That means they're measuring less than 100% of precious metal content in the rock.
That means that when they do get an accurate extraction process the assay results will only be higher than what we're getting now! How the hell is that a problem?!