Dominion Diamond Corp, formerly known as Harry Winston Diamond Corp, has secured all the required regulatory approvals to acquire BHP Billiton's Ekati diamond operations in Canada's North West Territories.

Dominion Diamond, based in Toronto, said it expects the deal to close on or around April 10.

BHP Billiton agreed last November to sell its 80-percent holding in the Ekati mine and related diamond sorting and sales facilities in Yellowknife in the Northwest Territories and Antwerp to Harry Winston for US$500 million.

Dominion says that national and provincial authorities had confirmed that it would receive regulatory approvals needed to complete the acquisition of BHP's stake in Ekati.

Dominion Diamond holds a 40-percent stake in the Diavik diamond mine in Canada's Northwest Territories around 100 kilometers to the southeast of Ekati.

Harry Winston has renamed itself as Dominion Diamond Corp. as part of a deal reached in January to sell its high-end jewelry arm to Swiss watchmaker and retailer Swatch for around US$1 billion.