Operating earnings before taxes (EBT) in the third quarter of its 2019/20 financial year ended June 2020 rose 91% on the year to 42 million euros ($49.35 million) with copper concentrate (ore) processing at a high level, Aurubis said.

The Hamburg-based company repeated it expected full-year group 2019/20 operating EBT of between 185 million euros and 250 million euros.

"Aurubis remains cautiously optimistic about the rest of the fiscal year," it said.

The impacts of COVID-19 on the raw material and product markets remain difficult for Aurubis to forecast.

"The past quarter was very challenging with regard to external factors due to the global coronavirus crisis," said Chief Executive Officer Roland Harings.

But flexibility and discipline of employees and crisis management meant the company kept coronavirus infection numbers at a very low level and continued production at smelter sites "largely unaffected", Harings said.

Aurubis also expects smelter and plant availability during the current fiscal year to exceed the previous year.

"Despite a reduced global supply of copper concentrates with low treatment and refining charges, Aurubis will be able to provide its plants with a good raw material supply due to both its good position on the market and the supply on the copper scrap market, which appears to be improving with rising refining charges," it said.

Treatment and refining charges (TC/RCs) are paid to copper smelters to refine concentrate into metal and are a key part of the copper refiners' income.

But Aurubis, which produces both new copper and copper products, said demand on copper product markets is "significantly lower" during the coronavirus downturn.

($1 = 0.8511 euros)

(Reporting by Michael Hogan; Editing by Michelle Martin and Rashmi Aich)