Investors know better than to place all their eggs in one basket.

Thankfully, an investment in Teck Resources (NYSE: TCK) is itself an exercise in that very discipline. Of course, Fools could acquire even more diversified materials exposure through a behemoth like BHP Billiton (NYSE: BHP), but I consider Teck a happy medium between a single-resource play and a catch-all basket of commodities.

I find that many still mistake Teck Resources for a base-metal play for copper and zinc, and that the miner is more commonly compared to competitors like Southern Copper (NYSE: SCCO) than it is to a rival like Peabody Energy (NYSE: BTU). Following its consolidation of Elk Valley Coal, however, Teck Resources is definitively a primary coal play, as nearly one-half of total revenue and operating profit in the third quarter was driven by sales of met coal.

Unfortunately for Teck, the export infrastructure in western Canada has struggled to keep pace with the miner's capacity, and congestion at port facilities led to a shortfall in coal sales for the quarter. Teck lowered full-year guidance for coal production accordingly, to a range of 23 to 23.8 million tonnes. In response to these challenges, Teck signed a confidential agreement this month with railroad Canadian Pacific (NYSE: CP), to haul Teck's coal from area mines for a period of 10 years. In return, Canadian Pacific will make investments in export infrastructure to keep pace with the miner's targeted production growth.

It is not yet clear whether this is an exclusive arrangement that will impact the ability of Canadian National Railway (NYSE: CNI) to participate in Teck's bituminous bonanza.

Just because copper has taken a back seat to coal within Teck's new structure, doesn't mean that copper operations will not vie for an increasing share of company profits going forward. Copper prices have also performed admirably, and Teck recently announced the start of commercial production at a new concentrate facility within the Carmen de Andacollo mine in Chile.

This new facility is expected to boost the company's total copper output by 26% to 340,000 tonnes per year. Considering that production growth alongside attractive copper assets in Teck's development pipeline, I concede the possibility that Teck's profile may gradually shift to one more evenly balanced between copper and coal. The company's zinc unit, while not to be ignored, accounted for around 20% of Teck's third-quarter operating profit.

For investors who well understand Teck's uncommon production profile, featuring two products that I consider to be deeply embroiled in a long-term secular bull market, Teck Resources will no doubt shine as a quality prospective investment. Since the stock has appreciated by more than 25% since I called Teck a golden ticket back in July, perhaps a modicum of caution is warranted with respect to fresh exposure here. To keep a closer eye on the company, try adding the ticker to your watchlist by clicking here.

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Fool contributor Christopher Barker can be found blogging actively and acting Foolishly within the CAPS community under the username TMFSinchiruna. He tweets. He owns shares of BHP Billiton and Peabody Energy. 

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