The company could have had months notice and then waited until last minute to announce it in case he changed his mind. I think you are reading into the 3 days thing unless you talked to someone at the company.
The stock isn't selling off because of the PR - the PR came out at 4:15PM. I seriously doubt there was any management discord that caused this. The guy is 65-70 years old. He's probably not short money. And all the major geology work is done for the near term. He still owns 13% of the company. I would guess they will not replace him immediately and he will contribute pro bono as needed.
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