Firestone Diamonds reported that full year losses narrowed by 52 per cent to 14.5m pounds after its revenues jumped thanks to robust diamond prices.The AIM-listed diamond miner, with operations focused on Lesotho and Botswana, said its corporate expense bill fell 17% in the year to the end of June while its care and maintenance costs halved. Firestone operates a pilot plant at the Liqhobong mine in Lesotho but plans to shut this down in the fourth quarter to make way for the construction of a main treatment plant. The company aims to become a 1m plus carat per annum producer from 2016.The pilot plant recovered 156,000 carats in the year to the end of June, down from 164,000 in the previous year. But it sold 166,712 carats at an average price of $93 a carat generating revenues of $15.5m.Firestone tapped the market for £3.8m in August and appointed Stuart Brown as Chief Executive designate last month. He will take the reins in December.Investec analysts said: "This company's shareholders have been diluted time after time with several equity issues in recent times. Financing discussions are well advanced regarding building the full scale Liqhobong mine and this at least is positive news."Shares in Firestone were flat at 3p at 12:25 on Friday. TB