Canadian diamond miner Dominion Diamond Corp (DDC.TO), which is being pursued by Washington Cos and Stornoway Diamond Corp (SWY.TO), said it would explore strategic alternatives, including a sale.

U.S.-listed shares of Dominion, which has a market cap of US$1.41 billion, were up 7.3 per cent at US$13.70 in premarket trading on Monday.

Dominion's largest shareholder, M&G Investments, last week asked the company to run a formal sales process and open its books to interested parties.

Washington Cos, a group of privately held North American mining, industrial and transportation businesses founded by billionaire Dennis Washington, revealed its $1.1 billion unsolicited bid in March.

Dominion, the world's third-largest diamond producer by value, broke off talks with the Washington Cos, calling the terms as unusual and unacceptable.

However, the miner said later that it was open to holding discussions with the Washington Cos.

Fellow Canadian diamond miner Stornoway Diamond Corp (SWY.TO) last week entered into talks with Dominion about a potential merger.

Dominion owns the Ekati diamond mine in Canada's Northwest Territories and a 40 per cent stake in the nearby Diavik mine.

TD Securities Inc is Dominion's financial adviser, while Stikeman Elliott LLP is the legal adviser.

Kingsdale Advisors is the strategic adviser.

Paul, Weiss, Rifkind, Wharton & Garrison LLP is acting as legal adviser to the company's special committee and the board of directors.