Gold stocks aren't usually a big favorite of value investors, but with the recent plunge in gold prices, a closer look at Yamana Gold ( TSX:YRI ) is warranted. Already boasting one of the lowest-cost operations in the industry, Yamana has historically benefited from not only its gold production but also the copper, zinc, and other by-product metals that result from its gold-mining operations. Yet weak gold price performance has pummeled the stock, and investors weren't pleased with the company's earnings report earlier this week, in which the company missed on both the top and bottom lines. In particular, weaker commodity prices across the board produced less offsetting revenue from by-product sales, raising cash costs. Even though it's in a low-cost position, Yamana plans to go further. Cost saving measures like better inventory management and worker layoffs are in the works.