Each investor charts his or her own road to success, but the best gurus I've known share one defining trait. Invariably, they approach each individual market with boundless inquisitiveness. Information and insight become the currency they most crave, while realized gains are more like gravy on that savory academic feast.

To the extent that time allows, I encourage all Fools with exposure to industrial and/or commodity stocks to carefully track the dynamics of coal. From steelmakers to railroads, coal impacts a surprising number of the stocks you may own. And whether you selected Massey Energy (NYSE: MEE) as a well-telegraphed takeover play, or the Market Vectors Coal ETF (NYSE: KOL) for a smattering of major producers (and related stocks), those with direct investment exposure will want to take particular care to seek insight wherever that may be found.

Coal through the eyes of a patriot
Eastern coal miner Patriot Coal (NYSE: PCX) shipped its fourth-quarter earnings to market Monday, offering an opportunity to dig for knowledge. Patriot investors will no doubt cheer the company's return to profitability. The miner dug up fourth-quarter income of $7.3 million, marking a dramatic improvement over the third quarter's $46 million hemorrhage and leaving industry analysts looking rather lowercase foolish. Collectively, the Street missed this call by a whopping $0.43 per share, expecting Patriot to post a $0.35-per-share loss.

In a nutshell, Patriot fell prey in 2010 to ramped-up regulatory scrutiny that found added zeal in the wake of Massey's tragic mine blast. More westerly focused miner Arch Coal (NYSE: ACI), by contrast, nearly quadrupled its full-year 2010 profit from prior-year levels. In fact, the nimble investor may have found greener pastures in 2010 by taking a westward migration to coal. As Patriot reengineered mines to maintain compliance, causing production volumes to dip and costs to rise, Patriot's underwater sales contracts leftover from its 2008 acquisition of Magnum Coal left their mark on the earnings statement.

Railroad operator Norfolk Southern (NYSE: NSC) referenced weather-related service disruptions in its quarterly report, so Fools are reminded that fourth-quarter sales volumes for the likes of Massey Energy and Patriot Coal were less robust than they could have been. Arch Coal appeared less than thrilled, characterizing eastern rail service as "poor." With export demand for both met coal and high-quality thermal coal gaining serious traction, the inquisitive Fool will wonder whether those weather-related issues are combining with the sort of rail capacity constraints that the coal industry endured prior to the global financial crisis. Last I checked, it seems the snow has never stopped falling, so investors may wish to build a margin of error into their first-quarter sales projections for the Appalachian operators. Inter-industry insight, you see, travels in two directions.

Have a metric ton of met
If persistent rail constraints were to trigger a sell-off, meanwhile, that might provide long-term-focused Fools a ripe opportunity to hop aboard Patriot's anticipated 59% growth spurt in high-margin met coal production over the next three years. As Massey-acquirer Alpha Natural Resources (NYSE: ANR) is keenly aware, met coal in particular represents some of the finest long-term market fundamentals of all industrial commodities.

Corroborating the outlook that Peabody Energy (NYSE: BTU) terms a global supercycle, Patriot Coal avows: "The structural shortage in metallurgical coal is expected to continue for at least the next few years, as a result of limited supply in established coal basins, coupled with long lead-times to bring on significant production in new basins." For coal investors focusing their related investments upon such bullish forecasts for met coal, unanimous agreement among all the world's producers can itself yield a golden nugget of valuable market insight.

Converting research to reason
Of course, performing effective due diligence is about so much more than just reading through corporate filings and absorbing all of the relevant information you can gather. Making sure we walk away from the exercise with the correct interpretations and a well-reasoned investment strategy is the most critical step in the process -- and that's where you come in. By letting investors with diverse perspectives and an incalculable array of life experiences discuss their favorite sectors, stocks, and investment strategies, the Motley Fool's vibrant CAPS community helps people sharpen analyses and hone strategies. For the naturally inquisitive investor, CAPS is an oasis of collective insight that makes each of us a better investor.

I recently added Alpha Natural Resources to my CAPS portfolio following its well-played bid for Massey Energy. If you're curious why I prefer Peabody Energy and Alpha over some of the sector's other options, come to my blog and ask. If you haven't joined CAPS, what are you waiting for? It's free! Your ideas are also welcomed in the comments box below to get the discussion rolling.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.