JOHANNESBURG (Reuters) - South Africa's stock market saw its biggest one day drop in nine months on Monday, dragged lower by iron ore producers and a sharp fall in cement company PPC after the abrupt resignation of its chief executive. Kumba Iron Ore, a unit of Anglo American, fell by almost 6 percent to 269.90 rand and Assore, dipped by 5 percent to 236.98 rand due to falling metal prices, prompted by fears of a slowdown in largest consumer China. The blue-chip JSE Top-40 index fell nearly 2 percent to 45,244 and the broader All-share index fell by a similar marging to 50,485. Chinese steel and iron ore futures hit record lows on Monday, hit by worries about excessive supply and dropping demand. "China's finance minister pretty much ruled out any major stimulus for the sector this weekend and that has put a lot of pressure on the miners," said Rabi Thithi, a trader with Avior Research. "The stronger dollar has also had an effect on commodity prices." The dollar has posted 10 straight weeks of gains, its longest winning streak since its free float in 1973. Shares in PPC slumped nearly 8 percent to 30 rand, a six-year low, after Ketso Gordhan quit as chief executive after clashes between him and the board. Cigarette maker British American Tobacco was the only company on the Top-40 that closed in the black. Trade was active with 184 million shares changing hands - above last year's daily average of 176 million - as 224 companies dropped compared to 84 gaining.