The top leaders involved in this year’s biggest gold mining deal are defending their transaction after a top investor called into question the takeover.

South Africa’s Gold Fields is seeking investor approval for its all-stock deal to buy Canadian miner Yamana Gold, a deal currently valued at C$6.8-billion ($5-billion). Some shareholders, however, have balked at the premium and structure of the transaction.

“It was not unexpected that this would take time for the market to understand,” Gold Fields CEO Chris Griffith said Friday in a TV interview with BNN Bloomberg. “There was quite a large shareholder base saying we don’t understand this.”

Van Eck Associates Corp., the biggest Yamana investor and the third-largest shareholder in Gold Fields, is critical of the transaction, the Globe and Mail reported Thursday. Portfolio manager Joe Foster called the deal “poorly structured” and said the market doesn’t understand the strategy behind the deal, the newspaper reported. Messages left with Foster weren’t immediately returned.

Another Gold Fields investor, Redwheel, called for the transaction to be scrapped in June.

Griffith says he “remains confident in our deal” and hopes to get the majority of investors on board by the time shareholders vote on the transaction. The Johannesburg-based miner will start international road shows to tout the deal starting next week. Yamana shareholders vote on the deal on Nov. 21, while Gold Fields investors vote on November 22.

“This is a great deal both in the short term for Yamana shareholders -- who will get the growth and the cash flow of Gold Fields -- and in the long term for Gold Fields, which will get the benefit of the portfolio of growth projects that come with the Yamana assets,” Griffith said.

Earlier Friday, Yamana executive chairperson Peter Marrone said in the company’s third-quarter earnings call that the transaction is a “well-structured and well-thought-through deal,” dismissing criticisms.

Yamana shares fell 2.8% to C$6 as of 12:25 p.m. in Toronto, below the C$6.70 value of Gold Fields’ offer. Earlier, shares in Gold Fields had fallen 1.4% in South Africa trading.

Gold Fields said May 31 that it sought to buy Toronto-based Yamana in an all-stock deal then valued at about C$9.2-billion, with the offer carrying an implied 34% premium.