UPDATE 3-Acacia-Tanzania proposed settlement on track -Barrick

(Recasts with Barrick statement, adds analyst and Barrick spokesman's comments, background, updates stock prices, changes byline) By Susan Taylor and Zandi Shabalala TORONTO/LONDON, Oct 20 (Reuters) - Barrick Gold said on Friday a proposed mining settlement it negotiated with Tanzania for its Acacia Mining unit was not under threat, even though Acacia said it could not immediately make a $300 million payment included in the deal. Barrick, which owns 63.9 percent of