Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of coal miner Alpha Natural Resources (NYSE: ANR) fell 11% today after Europe threw cold water on our global recovery plans.

So what: Coal miners are very sensitive to the macroeconomic picture because it drives coal prices, so today is a rough day. When Greece decided it needed to put its most recent bailout in a referendum the market panicked due to fear that the economic doldrums we're currently in will be drawn out further.

Now what: I'm not overly concerned about Greece or Europe as the driver of coal's prices right now. What I am concerned about is that problems in Europe will spill into China, where an insatiable thirst for energy has driven demand for coal higher for years. Watch these developments closely because they will likely be the biggest driver of coal stocks in the short-term.

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