Just some metallurgical study results from a small composite sample from the Epitaph zone (where that may be), so my comment is:
|RIP shareholder's money|
13376ppm to 13200 ppm, a whopping 176ppm decrease!!!!
I received an e-mail from David Michaud or 911 Metallurgy, and he sent me a link to an excellent article/Q&A on Mn in Pb and Zn concentrates
here is the link