The annual Rule Symposium in Boca Raton, a leading natural-resource investing conference, was held July 6 to July 10.

For its host, a five-decade sector veteran, Rick Rule, it is a legacy project — repayment, he says, for the mentorship older figures once extended to him.

"If I didn't do that myself, I would dishonor the debt I owe to those who taught me," he said in an interview.

The value on offer is not a hot tip.

Rule steers investors away from news, hype and emotion toward three measures he trusts: arithmetic, history and long-term structural trends.