Warren Buffett's silver purchase helped make Thomas Kaplan a billionaire. His gold bet is an even bigger boon: 'I owe him two!'

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· *Warren Buffett helped Thomas Kaplan become a billionaire when he bought 130 million ounces of silver in the late 1990s, just before Kaplan listed his silver-mining company.*
· *The Berkshire Hathaway CEO has done the natural-resources investor another favor by taking a stake in Barrick Gold last quarter.*
· *Barrick...