(IDEX Online) - Alrosa is expected to top its dwindling stocks with more rough diamonds from Gokhran, Russia's state repository.Last month the miner bought about 70 per cent of the 1.02m carats, which were sold at auction for a total of $139.2m, according to the Interfax news agency.Alrosa has been warning of "a long period of supply deficit" in the rough market as consumer demand outstrips supply from the mines and the midstream battles acute shortages.Gokhran is to hold another auction from its stockpiles in September, offering 768,600 carats worth about $19m.It is making an increasing volume of diamonds available at is sales. In four previous auctions Gokhran sold 1.2m carats of rough diamonds for $67m.