Anyone who thinks converting rising commodity prices into steadily expanding profits is a foregone conclusion for miners should think again. Wild short-term price fluctuations, rising costs, and transportation issues are among the many challenges miners must confront. When a secular bull market is powerful enough, though, investors are willing to overlook the occasional bump in the road.

Teck Cominco (NYSE: TCK) is a perfect case in point. Despite announcing net earnings of $0.78 per share for first quarter of 2008, 6% below last year's figure, Teck's shares are barely reacting. What could prompt such meager results amid a historic commodities boom?

First and foremost, kudos to fellow Fool contributor Toby Shute, who called this one back in January. The weakness of the U.S. dollar, and the relative strength of the Canadian dollar, was anything but optimal for Teck. Currency conversions shaved 10% to 20% from the price increases for most commodities, and exacerbated relative weakness in zinc prices by an additional 10%.

Another key factor affecting Teck's quarter was the company's big move into copper, just as the commodity was experiencing some weakness in price. After Teck purchased Aur Resources last year, copper increased as a percentage of operating income from 47% to more than 70% year over year. Teck recently announced that it will also purchase Global Copper to get its mitts on the prodigious Relincho project in Chile. This transaction will increase Teck's total copper resources by 25%. With these changes, Teck begins to compete more directly with Freeport-McMoRan (NYSE: FCX) and Southern Copper (NYSE: PCU). With copper prices rebounding, and the outlook favorable, investors are no doubt considering these factors as they forgive this quarter's earnings contraction.

Another beacon of hope on the horizon is the company's metallurgical coal operations. Teck should do very well on the segment, with prices for this coking coal going through the roof. Though rail transportation shortfalls, rising costs, and currency issues will all challenge these operations, the price hikes are significant enough to herald a reversal of fortune. As further enticement in the shares, savvy Fools seeking a long-term position should consider the company's plans for developing its oil sands properties.

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Fool contributor Christopher Barker captains yachts and writes about stocks. He can also be found acting Foolishly within the CAPS community under the username Sinchiruna. He owns shares of Freeport McMoRan and Teck Cominco. The Motley Fool has a disclosure policy.