text: Rio's offer of 16.50 Australian dollars ($16.42; Â£10.14) is now conditional on 47% of shareholders accepting it by 6 April.
  Previously its minimum target was 50%.
  The move came after talks on the A$3.9bn offer between Rio and Riversdale major shareholder, Brazil's CSN.
  If it fails to reach the new threshold, Rio Tinto will pay Riversdale shareholders only A$16 a share.
  So far only 41% have said yes.
  The other key shareholder in Riversdale is Tata Steel of India, which recently increased its stake to 27% and also has a director on the company's board.
  CSN, Brazil's largest steelmaker, has also increased its Riversdale stake to 19.9%.
target: Mining giant Rio Tinto has lowered its minimum acceptances target slightly in a last ditch effort to takeover South Africa's Riversdale Mining.