Brazilian mining giant Vale said Tuesday it has discontinued negotiations to acquire Switzerland-based miner Xstrata in a deal that could have turned it into the world's biggest mining company.

   The deal, which includes a cash and shares offer for 100 percent of Xstrata's stocks, could "have created significant value for both sets of shareholders," Vale said in a statement.

   According to local newspaper Valor Economico, the deadline for the completion of the negotiations expired on March 21.

   Vale registered its offer on Jan. 21 with Britain's Takeover Panel, an institution that regulates mergers and acquisitions in that country, as Xstrata holds stocks at the London Stock Exchange.

   From that date on, the two companies would have had two months to reach an agreement, Valor Economico said.

   Within the next six months, Vale will not be allowed to make another offer for Xstrata. But the Brazilian miner said it still "reserves the right to make and participate in an offer or possible offer" if Xstrata indicates it is willing to go ahead with a takeover.