JOHANNESBURG (Reuters) - South African stocks fell on Tuesday as iron ore prices continued their downward march, hitting companies such as ArcelorMittal, but platinum producers shined due to a slightly softer dollar. The benchmark Top-40 index fell 0.98 percent to 43,500 while the broader All-Share index skidded 0.92 percent to 48,712. Steel producer ArcelorMittal fell 2.4 percent to 37.50 rand as iron ore prices hovered near five-year lows, while Kumba Iron Ore slid 2.6 percent to 272.50 rand. Spot iron ore in Asia ticked up to $80 a tonne on Tuesday but the price is down 40 percent from the start of the year and hit a five-year low of $77.50 last week amid concerns about a slowdown in China, the world's top consumer of iron ore. Platinum producers bucked the downward trend, with the Johannesburg-listed sub-index up 3.9 percent on the back of a stronger spot platinum price. [ID:nL3N0S227S] Anglo American Platinum was the biggest climber in the Top-40, jumping 5.3 percent to 374 rand, its largest daily gain in more than a year. Smaller rival Impala Platinum rose 1.8 percent to 88.5 rand. "Platinum is having a good day. It was hit quite hard last week and the feeling is that it was oversold," said Rabi Thithi, an equities trader at Avior Research. A below-average 161 million shares changed hands. Decliners narrowly edged out advancers, 127 to 121. (Reporting by Zandi Shabalala; Editing by Ed Cropley)