The report found the deal was in best interests of OZ shareholders in the absence of a superior proposal.
The independent expert assessed the full underlying value of OZ at between $27.37 and $30.47 per share.
BHP is offering $28.25 per share cash.
The scheme booklet has been registered with the Australian Securities and Investments Commission and will be despatched to OZ shareholders.
OZ shareholders will be asked to vote on the deal at a meeting to be held in Adelaide on Thursday, April 18.
The board of OZ is urging shareholders to vote in favour of the deal.
The effective date of the scheme is expected to be April 18 with an implementation date of May 2.