Analysts at Credit Suisse have issued a short term trading sell on miner Antofagasta, on which they are broadly neutral, with a target price of 1,250p.The Swiss bank sees three short term drivers of underperformance. Firstly, consensus production estimates look too high by up to 10% over the period 2013-16. Secondly, the shares have outperformed peers and the copper price and valuation is at the top end of its ten year range. Third, copper price may underperform other commodities in the near term (given the resilient performance year-to-date and improving mine supply in the second half of 2012).Credit Suisse stresses that this is a trading call and that it continues to favour the the longer term outlook for copper and that Antofagasta has the qualities it looks for in a mining company longer term; "best in class balance sheet and operating cash flow margins, good disclosure and strong management and longer term growth optionality."CM