Pirquitas Tin Reserves Cut to Zero

Nov. 21 -- Silver Standard Resources has published new resource and reserve estimates for its Pirquitas mine in Argentina, which until recently had been expected to be a significant producer of up to 3,000 tonnes per year of tin as a by-product of silver mining. The new estimates reduce the estimated silver and zinc content of the ore-body significantly and exclude tin (previously estimated as some 80,000 tonnes) altogether.

In a statement the company said that tin would be excluded from its reserve estimates and cost calculations "until an economically viable processing method has been designed and tested." The start-up of a tin processing circuit at the mine was delayed and then halted in 2010 due to difficulties in achieving a satisfactory recovery rate in processing. The mine will produce between 7.3 and 7.6 million ounces of silver this year, together with some by-product zinc.