RE:RE:RE:8-10 Million More Support from Several Other Shareholders https://www.pinnaclecanada.com/yamana-gold-inc/72768 has his email address which seems to be similar structure to other yamana folks (eg https://sedar.com/DisplayProfile.do?lang=EN&issuerType=03&issuerNo=00003801). Not sure it's the best way but I have no clue in these matters.
I may have missed it but was the idea to let MBC know this "letter" is coming? Or just send them the letter if you pass the support level.