Johannesburg - Shares in South African iron ore producers Kumba and Assore rise in tandem with iron ore futures, which hit six-week highs amid optimism Chinese demand will remain firm after a sustained drop in stockpiles since the start of March.

Kumba shares trade 2.3 percent higher at 387.47 rand, making it the biggest gainer on the Top-40 index, which was up 0.21 percent. Assore adds 2.15 percent to 414.50 rand.

The most-active September iron ore contract on the Dalian Commodity Exchange rose 3.1 percent to settle at 825 yuan per tonne, after peaking earlier at 833 yuan, a level last seen on February 24. - Reuters