Trans-Siberian Gold swung to a pre-tax profit in 2014, as a sharp decline in operating costs drove revenue higher.In the year to 31 December, the Russia-focused gold miner posted a $1.3m (£0.8m) compared with a $16.5m loss in the previous year, as revenue edged up 4.3% year-on-year to $46.2m.The London-listed group said it margins were significantly improved by a sharp decline in operating costs, which fell 31.9% to $31.6m.Cost of sales per ounce of gold declined 42%, while administrative expensive fell 17.6% to $5.6m, although the drop was partly offset by finance expenses edging 3.1% higher to $3.3m and by a $0.5m loss related to currency headwinds.The group added gold production rose 21.6% to 39,089 ounces and silver production expanded 14.3% to 44,610 ounces, while gold prices averaged $1,256 per ounce in 2014 with silver averaging $18 per ounce, down 10% and 25% respectively from 2013.Trans-Siberian shares were down 4.35% to 11.00p at 11:30 on Monday.