By 2013 to take advantage of climbing prices LONDON (Reuters) - Lonmin Plc, the world's third biggest platinum producer, swung to an annual loss on weak prices and lower output, but said it planned to boost output by a fifth by 2013 as prices climb on shortages. Its shares gained as the company said it aimed for refined platinum production to rise gradually to 850,000 ounces by 2013 from 700,000 ounces in the current financial year to end September to meet a supply deficit. "We're working on the basis that we'll see a gradual recovery during 2010, with supply shortages expected from 2011 onwards," Chief Executive Ian Farmer told Reuters on Monday.