The Reuters/Jefferies CRB Index shows commodities jumped 29% in the first six months of this year - the best first half for more than 30 years.

But there is much talk now of a “commodities bear market” and the popping of the so-called “commodities bubble” as prices pull back from their highs.

Jim Rogers, however, remains a commodities bull. “This bull market is not magic,” says Jim, writing in Whiskey and Gunpowder. “It’s not some crazy ‘cycle theory’ I have. It does not fall out of the sky. It’s supply and demand. It’s simple stuff.”

Yesterday, oil was back up on a weaker dollar.

Crude oil futures gained $1.66 to settle at $114.53 a barrel on the Nymex. The euro, meanwhile, inched up 0.1% against the buck, off a six-month low of $1.4630.

Energy and oil expert Byron King says investors can expect oil to continue to head northward for all the familiar reasons. Oil’s long-term fundamentals are little changed since hit spiked to $147 a barrel at the end of July. And you can now pick up resource plays in 2008 at 2005 prices…

In energy news Thursday, oil prices rose, breaking a string of three consecutive losing sessions. Crude for September delivery gained $1.44 to $120.02 a barrel, while September reformulated gasoline went up 5.2 cents to close at $3.0027 a gallon.

Oil made two runs toward $150 recently, and failed both times. Now oil is in a retreat. Oil was trading near $121 earlier this week. And it appears that support at that price is crumbling. This will surely take the oil company stocks down, as well as those of the oil service companies.

If you’re bullish on mining, don’t buy the companies. Instead, buy the companies that make the shovels and picks… That was conventional wisdom years ago before gold-mining developed into a legitimate investment sector. But that old adage still stands true today - especially in the oil business.