Assmang, which is jointly owned by African Rainbow Minerals and Assore, said on Friday that production had resumed at the furnace shut down by the Department of Labour.

The furnace at Assmang's ferromanganese smelter in Cato Ridge was told to halt production on Wednesday after the Department of Labour discovered during an inspection at the weekend that molten metal had leaked from a hole in the furnace wall.

"Repairs to the furnace were completed yesterday following which the Department of Labour lifted its prohibition order," Assmang said in a statement.

"Burn-throughs of this nature are not unusual occurrences in furnace operations in South Africa and around the world, and at no time was there any risk to employees or the plant," the company said.

Assmang supplies raw material to the world's steel mills and alloy plants.

Damaged extensively in explosion

"Four furnaces are now operational at the plant, with the shutdown for planned maintenance on the fifth furnace progressing well," the company said, adding that the furnace was expected to be recommissioned mid-May.

The sixth furnace, damaged extensively in the explosion late in February, was due to be recommissioned in the fourth quarter of 2008.

All of the plant's furnaces were shut down after the massive blast that killed six workers and left several others injured.

Prohibition notices on the four furnaces now in operation were revoked last week.

Assmang's safety record has also been under the spotlight as an inquiry into the exposure of workers to poisonous fumes resumed this week.

The inquiry, being conducted by the Department of Labour, aims to establish the possible causes of manganism at the Cato Ridge plant and to consider remedial action.

At 4.40pm shares in African Rainbow Minerals were trading 1.31 percent or 3.50 rand down at 263.40 rand, while Assore's shares were 2.44 percent or 20 rand lower at 800 rand.

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