* Deal has approval of New Gold and Richfield boards
* Richfield has agreed to break fee of C$18 million
* New Gold shares down 4.1 pct; Richfield shares surge (Adds analyst comment, share price move, details on deal)
TORONTO, April 4 (Reuters) - New Gold Inc (NGD.TO) said on Monday it struck a deal to acquire gold exploration company Richfield Ventures RVC.V in a C$550 million ($567 million) all-stock deal that lets it expand its asset base in Canada.
The deal gives New Gold, a mid-sized gold miner, control of Richfield's flagship Blackwater project in British Columbia -- the acquisition will add about 3.8 million ounces of gold resources to New Gold's portfolio.
Under the deal, which comes amid soaring gold prices and bubbling gold sector M&A activity, Vancouver-based New Gold will swap 0.9217 of a share for each Richfield share. The deal values Richfield at C$10.38 a share, a 31 percent premium to its April 1 closing price.
"The acquisition of the Blackwater project is an ideal fit with our goal of continuing to enhance value in jurisdictions where we already have a strong presence," New Gold's Executive Chairman Randall Oliphant said in a statement.
Oliphant, the former president and chief executive of Barrick Gold (ABX.TO)(ABX.N), said the Blackwater project would significantly increase New Gold's production base at competitive cash costs in the years ahead.
New Gold owns operating assets in the United States, Mexico and Australia and is developing assets in Canada and Chile. The acquisition comes weeks after Oliphant signaled the company was on the lookout for advanced-stage exploration assets. [ID:nN09248931]
Fraser Mackenzie analyst Michael Starogiannis said in a note to clients that he believes the bid full and fair.
"We believe that the limits of the (Blackwater) deposit have been largely delineated by recent systematic drilling and are therefore unlikely to grow significantly," he said.
Shares of New Gold were down 4.1 percent at C$10.80, while those of Richfield were up 24.5 percent at C$9.88 on the TSX Venture Exchange.
The Blackwater project is a bulk-tonnage gold project in central British Columbia and is about 450 kilometers (280 miles) north of New Gold's New Afton project, which is expected to begin production in mid-2012.
New Gold, which expects to fund the development of Blackwater from internal cash flow, said the timeline to develop the project will allow it to transition its mine building team from New Afton to Blackwater.
Richfield CEO Peter Bernier said the all-stock deal would let Richfield's shareholders benefit from the advancement of the project, and from New Gold's larger portfolio of assets.
Moreover, in a business where the pedigree of a company's management team is almost as significant as the promise of its resource, New Gold's board of directors reads like a veritable who's who list of mining industry heavy weights.
Other board members besides Oliphant include Pierre Lassonde, the former president of Newmont Mining (NEM.N) and current chairman of Franco Nevada (FNV.TO); Ian Telfer, the current chairman and former CEO of Goldcorp (G.TO); and Raymond Threlkeld former CEO of Western Goldfields.
The boards of both companies support the deal and have set an C$18 million break-up fee. Richfield directors and officers, who control some 15.8 percent of its shares and options have agreed to support the deal, which requires approval of holders of two-thirds of Richfield shares.
New Gold's financial advisor is Canaccord Genuity and its legal advisors are Cassels Brock & Blackwell LLP in Canada and Shearman & Sterling LLP in the United States.
Richfield's financial advisor is National Bank Financial Inc. and its legal advisor is McMillan LLP in Canada. ($1= $0.97 Canadian) (Reporting by Euan Rocha and Pav Jordan; editing by Janet Guttsman)