Headline earnings rose to 2.4 billion rand ($204.4 million), or 23.55 rand per share, for the six months ended Dec. 31, from 21.05 rand per share a year earlier, the Johannesburg-based company said. Headline earnings per share strips out certain one-off items and is the main profit measure used in South Africa.

"Improved volumes across our range of products and better USD prices for all commodities in our basket, except chrome ore, were enough to overcome a 6 percent strengthening of the rand," said chief executive officer Charles Walters.

Assore said headline earnings was boosted mainly by Assmang, its 50 percent joint venture with African Rainbow Minerals , offsetting a 9.3 percent fall in earnings from the rest of the group's operations.

The company declared an interim dividend of 10.00 rand per share for the half year, up 67 percent compared with 6 rand declared in the same reporting period in the previous year.