Frack sand producer Hi-Crush Partners (HCRS.Q) has absolutely crushed the market this year. Units of the master limited partnership are up nearly 70% since I decided that the income from this proppant producer would make a nice addition to my portfolio. Unfortunately, in hindsight my decision to write puts on two occasions instead of just buying units turned out not to be the optimal decision. While I made more than 11% on my capital at risk, the conservative route left a lot of money on the table. Given its run this year, I'm wondering if there's still enough upside to make Hi-Crush Partners a buy.

What's fueling its rise?
Over the past week Hi-Crush's units jumped more than 15% after it settled a longstanding legal dispute with Baker Hughes (BHI). One of the reasons Hi-Crush's units were so cheap in the first place is because Baker Hughes notified the company last year that it was terminating its contract to purchase sand. Because the security of Hi-Crush's contracts are what enables it to pay a secure distribution, that caused investors to flee. Hi-Crush's new six-year contract with Baker Hughes removes a lot of that uncertainty.

This most recent development is on top of solid performance throughout the year. Hi-Crush's business is performing well, the company is growing both organically and by acquisition, and its future looks solid with oil and gas producers increasing the intensity of proppants used per frack.

Is the future now priced in?
With all of this good news taking units to such heights, one fellow Fool has suggested it's time to sell. That makes sense in this specific case because the investment was bought under the thesis that this was a special situation. Now that the catalyst has come to pass and Hi-Crush's intrinsic value has been reached, it's time to unload shares.

On the other hand, as an income stock I think Hi-Crush still holds value for investors. The current yield of slightly more than 6% is really solid in today's low-yield environment. Not only that, but the distribution should grow at a fairly high clip in the future. Hi-Crush has a lot of income growth that still hasn't been realized as its acquisition of D&I Silica is only just starting to produce dividends. Furthermore, Hi-Crush has a range of organic growth opportunities in addition to its ability to continue to acquire growth. So while Hi-Crush Partners isn't the bargain it has been, I still think income investors should do well by holding for the long term.

Is sand the best proppant?
That said, I don't think I'll personally take another shot at adding Hi-Crush to my portfolio by writing another round of puts. Quite honestly, while I think sand will continue to be used in greater quantities as a fracking proppant, I'm more interested in ceramic proppant maker CARBO Ceramics (CRR). Many producers, especially in the Bakken, are beginning to trumpet the virtues of ceramics to improve both initial production and estimated ultimate recoveries of oil and gas.

CARBO Ceramics has long trumpeted that its ceramic proppants can increase production by 20%-30%, as well as estimated ultimate recoveries by 30%. Many Bakken producers are reporting numbers even better than that, which is leading ceramics to become the preferred proppant of many developing the Bakken shale.

It's not just the Bakken. CARBO Ceramics was asked by one of its customers to develop a proppant that could withstand the pressures of places like the deepwater Gulf of Mexico to improve both production and estimated ultimate recoveries. To that end CARBO recently introduced Kryptosphere, which it calls an "ultra-conducive, ultra-high strength proppant" that represents a step-change for the industry. It's technological advances like this, as well as the evidence producers are seeing in the Bakken, that have turned my attention toward CARBO Ceramics.

Investor takeaway
Proppant producers offer investors an interesting way to play the shale gas and oil boom. That's why I still think that Hi-Crush Partners is a solid income investment for those with a long-term view. However, I personally view ceramics as playing a larger future role in the energy industry with CARBO Ceramics leading the way. It's going to the top of my watch list while I await a better buying opportunity, as its shares have also enjoyed quite the rise this year.

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