UPDATE 2.20pm: Shares in Regis Resources fell sharply after the gold miner warned it was continuing to battle the after-affects of flooding at its Rosemont and Garden Well mines in February.
The miner was forced to lower production expectations from its Garden Well mine from 190,000-210,00 ounces to 145,000-165,000 ounces, with pre-royalty cash costs up from $680-$730 an ounce to $900-$1000 an ounce.
Production at Rosemount was expected to be 65,000-85,000 ounces, up from earlier estimates of 48,000-53,000 ounces, but at uncomfortably high cash costs of $1000-$1100 an ounce pre royalty.
Moolart Well production would be in line with expectations of 95,000-105,000 ounces but pre-royalty cash costs would be up from $560-$610 an ounce to $600-$650 an ounce.
Regis gave overall production guidance of 305,000-355,000 ounces at cash costs of $835-$915 an ounce pre-royalty.
The company said it would look to optimise its operations over the next 12 months by focusing on mining schedules and throughput rates at both Garden Well and Rosemont.
It would also review all operating costs to extract the best available efficiencies from all areas of its operations.
Gold bullion for immediate delivery is trading at $US1293.83 an ounce in Singapore.
Regis shares plunged 57 cents, or 25 per cent, to $1.71 at the close.