Investors looking for stocks in the Mining - Miscellaneous sector might want to consider either Billiton (BBL) or BHP (BHP). But which of these two stocks offers value investors a better bang for their buck right now? We'll need to take a closer look.There are plenty of strategies for discovering value stocks, but we have found that pairing a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system produces the best returns. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.Currently, both Billiton and BHP are holding a Zacks Rank of # 2 (Buy). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that these stocks have improving earnings outlooks. But this is only part of the picture for value investors.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.BBL currently has a forward P/E ratio of 9.31, while BHP has a forward P/E of 11.39. We also note that BBL has a PEG ratio of 2.25. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. BHP currently has a PEG ratio of 2.75.Another notable valuation metric for BBL is its P/B ratio of 0.85. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. For comparison, BHP has a P/B of 1.57.These are just a few of the metrics contributing to BBL's Value grade of A and BHP's Value grade of C.Both BBL and BHP are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that BBL is the superior value option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report BHP Billiton PLC (BBL): Free Stock Analysis Report BHP Group Limited (BHP): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research