If you're interested in coal, metallurgical coal might be the best sub-market to look at. Met coal is rare, has gone up in price from $30/ton to $210/ton in the last decade and a half, and has massive demand baked in for the next decade as the developing world builds infrastructure and develops automobile markets. Massey Energy recently delivered an excellent overview of the met coal market -- here's their presentation:
http://phx.corporate-ir.net/External.File?item=UGFyZW50SUQ9Mzk3NDQwfENoaWxkSUQ9NDAzNzM4fFR5cGU9MQ==&t=1
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