It all boils down to credibility.
I am not aware of any mining operation that has a 100% gold recovery rate. There is always gold remaining in the tailings (usually a low enough amount that it's not worth the cost of contnuing to process or re-process). Maybe they are getting a 98% recovery, which woudl be great, but be accurate and honest about that data.
That Mexus is boasting an impossible 100% recovery rate further demonstrates how cavalier they are about putting forward accurate data.
Mining is a technical process. It can be the difference between actually recovering gold or havng a 250lbs bucket of zinc sludge ladened with gold that can't be separated.
These little details do matter, if for no other reason than to demonstrate competency - something Mexus has not done a good job conveying.