News: SBM UPDATE 1-Australia's St Barbara backs Genesis' offer for Leonara assets over Silver Lake...

(Adds details on counter-proposal)

May 4 (Reuters) -

Australian gold miner St Barbara Ltd (SBM) on Thursday said it will back a A$600 million ($400 million) offer for its Leonara assets from Genesis Minerals Ltd (GMD) , despite a higher proposal from Silver Lake Resources Ltd (SLR) .

St Barbara rejected Silver Lake's A$732 million offer, citing a lack of synergies and a lower cash component.

"Silver Lake has not provided any reasonable or quantitative assumptions to support its proposed offer price which could otherwise be confirmed via due diligence," St Barbara said in a statement, adding that a transaction with the company would also likely take longer to complete.

Even if the required mutual due diligence could be completed within two weeks, Silver Lake indicated that expected completion of a transaction would occur in mid to late August, St Barbara said, whereas a deal with Genesis is likely to be completed by June 30.

"Silver Lake is surprised and disappointed that after limited engagement regarding the Silver Lake Proposal, the St Barbara Board has advised that it will not engage further," it said.

It added that two of St Barbara's stakeholders - L1 Capital and Baker Steel Capital Managers LLC were in favor of granting Silver Lake due diligence.

($1 = 1.4993 Australian dollars)