Prepare to witness another dimension where nothing is as it seems. You are about to enter the coal stock twilight zone. Lying between a convoluted earnings statement and results that fail to inspire: Alliance Resource Partners (NASDAQ:ARLP).

The twilight zone begins at the earnings release, where an apparent drop in income for the second quarter is actually a 6.8% increase over the prior year, once a dizzying mix of non-recurring items is accounted for.

Before the recent explosion in coal prices, Alliance Resource Partners was a sector leader in profitability, enjoying EBITDA margins well ahead of worthy competitors such as Arch Coal (NYSE:ACI), CONSOL Energy (NYSE:CNX), and Massey Energy (NYSE:MEE). As prices for metallurgical coal remain near the $300 mark -- and could go higher still -- however, Alliance's lack of exposure to this coveted coal grade likely will allow those competitors to close the profitability gap very quickly.

This leads me to a second journey into the twilight zone. How is it, Rod Serling might have asked, that the fourth-largest coal producer in the eastern United States posts single-digit earnings growth while Fording Canadian Coal Trust (NYSE:FDG)'s profit rises by 252% and Arch Coal's earnings triple? To be sure, the lack of met coal production is a key factor, but even steam coal prices have risen more than 100% in recent months. Why, then, is Alliance Resource Partners' average sales price up only 2.3% to $39.50 per ton? For one thing, 75% of Alliance's coal production is from the Illinois basin, which sells for much less than Appalachian steam coal. Secondly, Alliance signs long-term supply contracts with domestic utilities, creating a lag between realized sales prices and rising market spot prices.

In a sector with the kind of volatility that coal has experienced recently, a conservative choice like Alliance Resource Partners may suit some Fools' tastes. For income-seeking Fools who invest by the "slow and steady wins the race" mantra, Alliance offers a 5.5% dividend, a track record of steady production and revenue growth, and a conservative strategy that is likely to work in any price environment for coal.

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Alliance Resource Partners is a Motley Fool Income Investor recommendation. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Christopher Barker captains yachts and writes about stocks. He can also be found blogging actively and acting Foolishly in the Motley Fool CAPS community under the username TMFSinchiruna. He owns shares of Arch Coal and Massey Energy. The Fool has a disclosure policy.