Mexican precious metals producer Fresnillo made an impressive start to 2015 with both silver and gold output up significantly over last year, putting the company on track to hit its annual targets.The group said it expects to achieve its 2015 production guidance of 45-47m ounces of silver and 670,000-685,000 ounces of gold.Fresnillo reported 12.4moz of silver production in the three months to 31 March, up 18.9% on last year.This was due to increase ore volumes processed and higher ore grade at its Saucito project, which more than made up for lower output at its namesake Fresnillo mine.Gold output was 62.4% higher at 182,000oz, with the Herradura site becoming fully operational after the temporary suspension of an explosives permit which affected production in the first quarter of 2014.Results were also helped by the now-operational leaching plant at Herradura and an increased contribution from Saucito.Chief executive Octavio Alvídrez said Fresnillo made a "strong start" to the year."We have improved development work at Fresnillo and started to see the results of the measures being taken to solve the challenges faced at Herradura," he said."Looking ahead, we have seen continued progress at our San Julián development project, with stage one on schedule for commissioning in late 2015, and stage two to follow in 2016. I am confident that we remain on track to achieve our 2015 production guidance."The stock was up 1% at 729.9p in early deals on Wednesday.