An independent evaluation has put Yamana Gold's mineral assets at between $6-billion and $8-billion, in line with South Africa's Gold Fields' initial offer price for the Canadian miner, circulars issued late Friday showed.

Gold Fields announced a deal to acquire Yamana in an all-share transaction that valued the Canadian company at $6.7-billion on May 31.

But investor concerns that the deal was dilutive and over-valued Yamana sent Gold Fields' shares tumbling 20% on the day of the announcement.

The spread between the value of Gold Fields' offer and Yamana's share price has narrowed following the share slump.

A valuation report produced by CIBC World Markets on August 30 had valued Yamana's mineral assets, which include 50% of Canadian Malarctic - one of the world's biggest gold mines - at between $6.825-billion and $8.025-billion, according to the circulars.

CIBC, one of Canada's biggest investment banks, said its report did not evaluate Yamana as a corporate entity and excluded the firm's expenses and interest on debt held at the corporate level.

Gold Fields and Yamana did not provide financial projections but used 2021 financial reports to show that the combined entity would have reported $6-billion revenue and $744-million annual profit if the deal was executed on January 1 last year.

Both firms' boards said they unanimously backed the transaction, which would see Gold Fields owning 69% of the merged entity and current Yamana shareholders holding 31%.

"The combined company will be a top-4 global gold major with a diversified portfolio of high-quality, long-life assets with tangible near and long-term growth opportunities," the directors said.

Gold Fields has said Yamana gives it a coveted foothold in North America and brings new assets on board at a time the industry is faced with depleting reserves.

Yamana and Gold Fields shareholders will vote on the deal on November 21 and November 22, respectively.

The transactions require the approval of 75% of Gold Fields shareholders, while Yamana needs 66.67% support.