Shares in Navigator Resources slumped after the company lowered June quarter production guidance from its troubled Bronzewing gold project to 15,000 ounces, down from 19,989 ounces in the previous quarter.
The company said it had decided to concentrate its earthmoving fleet in the Cockburn Pit, where the bulk of its ore reserves existed, for the coming year to obtain optimum operational efficiencies and access higher grade ore in the earliest possible timeframe.
"Waste pre-stripping commenced at Cockburn during January, with first ore expected to be mined in September," Navigator said in a statement
The company said full scale ore supply from Cockburn to the processing plant would be achieved by the end of the March 2012 quarter.
Navigator shares were off two cents, or 11.43 per cent, to 15.5 cents at 9.25am after falling as low as 14.5 cents in earlier trade.