Congo's Katanga province suspended cobalt concentrate exports from the country'smineral heartland on Tuesday for at least a week, accusing companies offlouting curbs on raw ore exports, the provincial governor said.

I have stopped all exportsof cobalt concentrate, because there are companies that are just crushing rawore and saying it is concentrate, Governor Moise Katumbi told Reuters bytelephone from Katanga's provincial capital, Lubumbashi.

A team of engineers was due toarrive in Katanga next week to inspect mining operations and ensure companies werefollowing proper procedures before exports would be permitted to resume,Katumbi said.

Katumbi closed the province'sborder with neighbouring Zambia in March 2007 in an effort to stop the export ofraw minerals and force companies to produce value-added processed productsinside Democratic Republic of Congo.

Coupled with a crackdown oncorrupt customs officials, the ban had largely been considered a successdespite some reports of continued smuggling.

Mining companies contacted byReuters on Tuesday said they had not yet been informed of the decision tosuspend cobalt concentrate exports.

Koen Delapierre, Africa director for Belgian logistics company Polytra, the largest transporterof processed ore from Katanga, said he was still checking whether the company'strucks had been allowed to cross the border into Zambia.

The information has justcome down. I have to call the border. I have to call everyone to find outwhat's happening, he said.

Congo's mining code specifies that raw ore should only be exported when itcannot be processed domestically. Katumbi's decision to enforce the rule lastyear was part of an effort to boost tax revenues from Katanga's booming mining sector.

Concentrate is created byseparating minerals from waste material through chemical flotation or densemedia separation in one of the first stages of mineral processing.