The above companies are only marginally lower today. After adjusting for a drop in the S&P 500 of over half a percent, as seen by the SPDR S&P 500 ETF ( SPY), the coal-related stocks are essentially flat. This sets up a buying opportunity for long-term investors. Because this is a long-term play, I especially like selling option premium, so we get paid for our time while lowering our risk. Here is one idea that you may consider. Option activity for Cliffs Natural Resources has climbed recently, especially this week, and the stock is oversold technically. This sets Cliffs slightly ahead of the pack. But any of the above coal miners are viable candidates. Follow @RobertWeinstein This article was written by an independent contributor, separate from TheStreet's regular news coverage.