Mar. 21 (Bloomberg) - Copper treatment and refining fees have fallen to $30 to $40 a metric ton and 3 cents to 4 cents a pound this month, said Aurubis AG (NDA), the second-biggest refined copper producer.

The spot market fees compare with more than $50 a ton and 5 cents a pound in February. Agreements under long-term contracts are unchanged at $63.50 a ton and 6.35 cents a pound, the rates set for the year.

"There is not so much spot business at the moment," Peter Willbrandt, chief executive officer of the Hamburg-based company, said in a phone interview yesterday. "We foresee the spot TC/RCs will increase during the next couple of weeks" as Freeport McMoran Copper & Gold Inc.'s Grasberg mine resumed operations and more concentrate is available. Copper smelters in South America may face disruptions too, he said.

Production at the Grasberg mine, which contains the world's biggest recoverable copper reserve, was cut in 2011 because of a three-month strike that ended in December. The company resumed mining and milling operations last week after a temporary halt on Feb.23.

"After the Grasberg mine has restarted, the pressure on the market will ease," Willbrandt said.