Buffet hasn't been relevant in twenty years. Remove Apple from its holdings and you have a very bad ten year track record.
Buffett not buffet.
BRK-A closed at $116,700/share on 8/16/2010 and closed at $316,251/share yesterday. This works out to 10.5% compounded annually over the ten-year period.
I'm not sure how 10.5% compounded annually can be interpreted to constitute a "very bad ten year track record", a "somewhat bad ten year track record", or even a "little bit bad ten year track record".
There are three people responsible for portfolio investments at BRK, two of which are "new" investment managers who have been there for about ten years and who each manage a portfolio in the very low eleven figures (double-digit billions). Buffett manages the rest of the portfolio (triple digit billions). There are lots of other managers, but these manage individual business units rather than investment portfolios. There is no large staff of security analysts.
The Barrick position is a relatively small one, and therefore almost certainly selected by one of the "new" investment managers and not by Buffett himself. BRK doesn't disclose which portfolio manager is buying or selling which security. The "new" investment managers have no obligation to discuss any purchase or sale with Buffett in advance, although there is a short list of securities which they are not allowed to own due to potential real or perceived conflicts of interest.
For those who are interested and analytically inclined, trying to figure out what the portfolio manager is seeing in Barrick would be an interesting exercise. This may or may not end up being a good investment, and the verdict cannot be issued until the position has been sold and the check has cleared, which may be years or decades from now.