United States Dollar  
  Figures in millions unless otherwise stated 2018      2017  2016   
29. CHANGE IN WORKING CAPITAL            
  Inventories 0.8      (55.1) (39.2)  
  Trade and other receivables 15.0      (2.2) 2.8   
  Trade and other payables (32.1)     (12.1) 34.1   
  Total change in working capital (16.3)     (69.4) (2.3)