Democratic Republic of Congo's mineral-rich Katanga province is enforcing a suspension of cobalt concentrate exports, the provincial governor said on Friday.

"No one is getting through now," governor Moise Katumbi told Reuters. He had announced this week the suspension would start from Thursday, saying companies were flouting measures prohibiting the export of raw ore.

The provincial government of the southeastern mining province is seeking to halt the export of raw minerals and force companies to produce value-added processed products, such as cobalt metal, inside Democratic Republic of Congo.

Katumbi, speaking by telephone from the provincial capital Lubumbashi, said Thursday had been the last day for companies which had cobalt concentrate stocks to export them.

But, offering the prospect of exceptions to the suspension, he said some companies which had started to build factories to produce metal would be able to continue exporting concentrate when a list of all the operators was drawn up next week.

"I banned the export of raw ore a year ago. We gave companies 24 months (to begin exporting metal). We are now at 12 months, and they have 12 more months to finish their factories," he said.

"But there are many companies that still don't even have concentrators. They are just crushing and washing the ore," Katumbi added.

Katumbi closed the province's border with neighbouring Zambia in March 2007 in an effort to stop the export of raw minerals.

Congo's mining code specifies that raw ore should only be exported when it cannot be processed domestically. Katumbi's decision to enforce the rule last year was part of an effort to boost tax revenues from Katanga's booming mining sector.

Concentrate is created by separating minerals from waste material through chemical flotation or dense media separation in one of the first stages of mineral processing.