The mining industry has been taking its lumps of late, with coal, iron ore, and copper, among others, all seeing price and/or demand pressures. That's left the industry in a weakened state. However, companies aren't sitting around to wait out the downturn—some are taking action now.

Sticking to what you know
The most common thread for expansion is to stick with what you know. For coal miner Rhino Resource Partners (NYSE:RNO) that means energy. About 90% of the company's top line comes from coal. Its "other" revenues are increasingly coming from natural gas drilling. In July, the company reported having 15 natural gas wells.

Obviously this is still a new business, so revenue growth has been impressive. That should slow as the gas segment grows. Balancing coal with natural gas, however, should put Rhino in position to benefit no matter which fuel source is favored by utilities over the long haul.

This is the strategy that CONSOL (NYSE:CNX) has successfully followed for years. In fact, with the coal markets so weak, the company is set to shift its capital spending toward natural gas. Starting in 2014, money being spent on the coal business will be at "maintenance" levels.

So CONSOL has more flexibility than Rhino to benefit from natural gas' increasingly important role in the U.S. electric industry, making it an interesting option all on its own. However, the company's success at navigating the coal market's downturn points to an improved outlook for Rhino. CONSOL has been posting only small quarterly losses at a time when many coal-focused companies have been dealing with much deeper bottom line issues.

Rhino's push into the gas space should eventually yield that type of diversity. That's also what Natural Resource Partners (NYSE:NRP) is hoping for with its push into natural gas drilling. Like Rhino it's only just getting started.

Going a bit wider afield
But Natural Resource Partners' business extends well beyond coal and gas. It also includes such things as limestone and slate. And it recently made a notable move into the soda ash business, with the nearly $300 million purchase of an interest in OCI Wyoming. OCI Wyoming is the fifth largest soda ash producer in the world. Soda ash is used in such things as glass, chemicals, soap, and paper.

So, unlike natural gas, adding soda ash to the fold will push Natural Resource Partners well past the energy patch. That should provide an important level of diversification, even beyond the 30% of revenue that already comes from non-coal royalty businesses. Don't expect an overnight transformation for this coal partnership, but the OCI purchase and its other non-energy opportunities point to a future that is much less dependent on energy markets.

More ash, more food
Another notable move in the "ash" space is the billions that BHP Billiton (NYSE:BHP) is spending to build a potash mine in Canada. Potash is used for fertilizing food crops. BHP's other businesses are things like iron ore, copper, coal, and oil. Clearly, this shift is a little far afield, but that will bring with it important diversification benefits.

The problem is that the mine is just a hole in the ground and won't produce any potash for years to come. However, that's one of the reasons why BHP is the perfect company to develop it. As the CEO of Potash Corp. (NYSE:POT) explains, potash is a "difficult business to get into. There are large barriers to entry." Those barriers are largely time and money. BHP has plenty of both, particularly since it has remained profitable despite the downturn in most of its core business lines.

And potash is likely to be increasingly important since improving crop productivity will be vital to support growing populations in emerging markets. That's one reason why Potash Corp. is feeling so positive about its future despite some recent pricing pressures in the industry, which accounts for about half of the company's top line.

That said, Potash is quick to point out that demand isn't based on cost. Farmers buy the fertilizer they need; cheap prices don't spur additional purchases. Thus, price wars aren't likely to be a long-term concern. In fact, BHP's project should benefit from the fact that it isn't up and running yet, since that lead time will allow global demand to increase.

From the "ashes"
Although investing in the development of a potash mine is going to be costly for BHP today, the long-term benefit should be an even more stable and diversified business. Natural Resource Partners, meanwhile, will start to see the benefit of its soda ash investment right away. That should further diversify it away from its heavy reliance on coal. These "ash" plays appear to be solid moves for both companies.

Reuben Brewer has positions in Natural Resource Partners and Rhino Resource Partners. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.