LONDON, Sept 11 (Reuters) - Japan's largest copper producer JX Metals Group said on Monday its Saganoseki smelter is operating normally despite market talk and that the plant will be shut for planned maintenance late next month.

Four sources familiar with the matter had told Reuters last week that JX Metals was offering copper concentrate on the spot market to other producers of the metal in China and Japan, adding the offers were due to a suspension at its Saganoseki operation.

The sources also said the smelter which turns concentrate into copper metal had been closed for more than a week.

"The Saganoseki Smelter and Refinery is operating normally, and it is not true that it has been shut for more than a week," JX metals said in an emailed statement.

"The planned maintenance at the Saganoseki Smelter and Refinery is scheduled to begin in late October, as previously scheduled."

Copper wire and cable are widely use in the power and construction industries.

The Saganoseki copper smelter with capacity to produce 450,000 tonnes of copper a year.

JX Metals, owned by Japan's energy company Eneos Holdings, buys approximately 1.8 million tonnes of copper concentrates every year mainly from mines in Chile called Caserones, Los Pelambres, Escondida and Collahuasi.

Japan is a net exporter of copper. The country produced 1.6 million tonnes of refined copper last year and consumed 905,300 tonnes, according to International Copper Study Group.

The Asian country is the second largest buyer of copper concentrate after China.

(Reporting by Julian Luk; additional reporting by Yuka Obayashi; editing by Timothy Gardner)