Toronto-based Dominion Diamond Corp. said in a statement that it has all necessary approvals from regulators to buy BHP Billiton's Ekati diamond operations in Northwest Territories, Canada.

Formerly known as Harry Winston Diamon Corp., Dominion Diamond said that the deal is expected to be closed on or about April 10. It announced that regulatory approvals will be given to Canada and Northwest Territories required to complete the acquisition of BHP's shares in the Ekati diamond mine.

Last November, BHP Billiton, an Anglo-Australian mining firm, agreed to sell its stake to Harry Winston for $500 million.

In a separate transaction in January, Harry Winston said it is planning to make sale of its high-end jewelry unit to Swiss watch manufacturer Swatch.