2. Canada-based PolyMet Mining ( PLM) is a development-stage company engaged in the exploration and development of natural resource properties. A CIBC junior copper report has ranked Polymet first for lowest cash costs and maximum production per dollar of capital expenditure among peers. For the second quarter ending July 2010, the junior miner's capital expenditure stood at $4.17 million as compared to $14.66 million recorded by peer Augusta ( AZC) and $8.08 million by Taseko in its first quarter. During May 2008, the company recorded copper cash costs of $1.05 per pound, which is on par with the current average cash costs of $1.01 per pound recorded in the Chilean industry, the world's biggest producer of the red metal. BNAmericas cites a study by Cochilco, which expects cash costs to remain flat at $1.01 through 2011 and then decrease to $0.93 per pound by 2015. PolyMet's major mines are NorthMet Project and Erie Plant. The company says that its Erie plant has the capacity to operate at almost three times the planned production rate. Additionally, any expansion in production can be backed by a reserve expansion at NorthMet and other identified deposits in the area. The stock is trading at a price-to-book ratio of 2.6, which is lower than its peers and, therefore, indicates a buying opportunity for investors.