Randgold Resources led the FTSE 100 fallers after warning that the political crisis in Ivory Coast would hit gold production at its Tongon mine.
Chief executive Mark Bristow said Tongon was continuing to operate, "albeit on a curtailed basis". Key components have been held up in the port of Abidjan and by the shipping delays caused by the unrest in the country.
"We knew that 2010 was going to be a challenging year and the fourth quarter is turning out to be even tougher than anticipated," said Bristow.
Randgold shares were almost 5% lower by mid-morning, falling 245p to £52.55.
