Increased production and a recovery in rough diamond prices helped Petra Diamonds boost gross mine revenue by 88% in the year to 30 June.Revenue jumped to $177.7m during the period from $94.4m in 2009, helped by the sale of the 507 carat egg-sized Cullinan Heritage diamond in February for $35.3m. Gross production rose 6% to 1.165m carats and the amount of diamonds sold grew by 11% to 1.125m carats.The group, which raised $120m (£72.7m) from a placing in December and agreed terms for debt facilities totalling $78m, "is now fully financed to roll out its planned capital expansions to treble annual output to over three million carats, by increasing production from its world-class resource base".It also increased its ownership of the Cullinan mine to 74%, doubling Cullinan's attributable production and increasing Petra's attributable resource base from all operations to 195 million carats."Exciting demand growth continues at double digit pace from China and India, with market commentators predicting that China could grow to equal the US diamond market within the next decade," Petra said.Though global rough diamond supply will be higher this year than in 2009, due to increased sales from De Beers and Alrosa, Petra thinks supply constraints will result in a significant shortfall to the market, which will emerge in the next three to five years.