Lynas Corporation has flagged a 30 per cent jump in full year pre-tax loss due to higher operating costs at its Mt Weld rare earths mine in Western Australia as production is ramped up.

Lynas shares had fallen by nine cents, or 7.03 per cent, to $1.19 by 1218 AEST after the miner said it expected a loss before income tax for the year ended June 30 of $57 million.

More than 43 million shares had changed hands, making it the second-most-traded stock by volume.

The company revealed the forecast in a response to a query by the Australian Securities Exchange (ASX), which noted a slump in Lynas’ share price since closing at $1.46 on Tuesday.

The ASX also noted an increase in Lynas’ trading volumes over this period.

Lynas said, in a statement on Thursday, it was not aware of any information that had not been announced that could explain the recent trading.

However, it said it expected an approximate 30 per cent increase in pre-tax loss for 2010/11.

“This is primarily due to increased operating costs incurred as the group ramps up towards first production,” Lynas said.

First ore was fed into the Mt Weld processing plant in May.