* Equinox says Minmetals' bid significantly undervalues company
* Says bid a long way off from being a formal offer
* Minmetals says offer compelling, Equinox response "predicatble"
* Equinox shares off 0.7 pct, but well above offer price
* Investors wait for higher offer to emerge (Adds quotes, details)
By Victoria Thieberger and Euan Rocha
MELBOURNE/TORONTO, April 8 (Reuters) - Equinox Minerals said a $6.6 billion bid from China's Minmetals Resources was too low, leaving the door open to a rival offer as miners vie for access to valuable copper deposits.
Speaking after the rejection, a Minmetals spokeswoman said the offer was compelling and the response from Equinox was "predictable."
China, which accounts for 40 percent of the world's demand for copper, is on a mining acquisition spree and is chasing Equinox's copper assets in Zambia and Saudi Arabia as prices for the red metal hover near record highs.
"Yes the offer is lowball, but it puts them in play," said Grant Craighead, managing director of the Stock Resource group in Sydney, which holds Equinox shares.
"Equinox has got the long-life, quality assets that large companies are looking for and accordingly there is the risk this will flush out other bidders in the process," he said.
Minmetals, a state-controlled Chinese entity and the nation's biggest metals trading firm, wants to move into the top three of mid-tier diversified mining companies in the next five years, through internal growth as well as acquisition.
Equinox shares in Sydney eased 0.7 percent to A$7.43 after the company's statement, but remained well above Minmetals' C$7 per share offer, indicating investors expect either Minmetals to come back with a higher offer, or a rival bid to emerge.
The shares in Toronto closed at C$7.50 before the statement came out.
"We consider that the lowball price announced by MMR significantly understates our value and disregards the potential of this company, especially in light of the continuing strength in copper prices," Equinox Chairman Peter Tomsett said in a statement.
Tomsett said no formal offer had been made, and nor was one expected for several weeks because several approvals were needed first.
He alleged the purpose of the Chinese bid seemed to be to frustrate Equinox's own bid for Canadian rival Lundin Mining . The Toronto-based miner contends that its offer for Lundin would add significant value for shareholders of both companies.
But investors had marked down Equinox's shares after it made the hostile offer for Lundin, paving the way for the Minmetals bid.
"They've almost got themselves to blame for the situation they find themselves in. Equinox took on the risk and it made them vulnerable to predators," Stock Resource's Craighead said.
SECURING RESOURCES
Investors said rival bidders might be deterred by Minmetals' financing power.
"If we look forward from now on, any one of your big resource companies will have to compete with the Chinese," Northward Capital portfolio manager Michael Bentley said.
While Minmetals has a market value of just $2.5 billion, the metals trading firm said its bid was being funded with credit from Chinese banks and equity investments by Chinese institutions .
The main attractions at Equinox are its Lumwana copper and uranium mine in Zambia, Africa's third-largest copper mine by production, and the Jabal Sayid copper development in Saudi Arabia, due to start production next year.
Those mines could attract Xstrata , Antofagasta , Vedanta Resources and possibly Norilsk Nickel , analysts said.
"There is still a way to go on this. There are not a lot of copper assets like this around the world at the moment that have 40-year mine lives, and not a lot of new projects," Bentley said.
China, and to a lesser degree India, have been scouring the globe to secure resources to fuel their fast-growing economies. Chinese banks have lent African nations billions of dollars and committed to fund major infrastructure projects as they drive for access to copper, iron ore, food and other resources.
Surging global demand for copper plus the high cost and long lead time to bring new resources to production have fueled expectations of more takeover activity and a prolonged bull run in the metal. [ID:nN03156338]
London Metal Exchange copper touched a record high of $10,190 a tonne in February, and was at $9,730 on Friday. It has risen some 120 percent in the past two years.
APPROVALS REQUIRED
Outlining delays to a formal offer, Equinox said the bid by Minmetals will require the approval of China's National Development and Reform Commission, which has yet to be received.
The Chinese bid also requires the approval of Minmetals' own shareholders. While ChinaMinmetals Corp, Minmetals' largest shareholder, has agreed to vote in favor of the deal, the vote will only be held after the NDRC approves the bid.
The Minmetals shareholders meeting is not expected to occur until sometime in June, Equinox said, adding that it can only respond to Minmetals after a formal offer is submitted.
It would be China's fourth-biggest outbound M&A deal, according to Thomson Reuters data.
A senior Canadian M&A banker, who asked not to be named, said Equinox's chances of clinching a deal with Lundin were extremely low in light of the Minmetals bid.
"I think that's over. The thing about Equinox is they really stretched to go after Lundin financially. Their shareholders didn't like it, their stock came off, and that put them right square in the sights of Minmetals," he said.
"It was a bit of a miscalculation on their part because it exposed them to a hostile takeover, which is exactly what happened," he added. (C$ = $1.043) (Additional reporting by Pav Jordan in Toronto and Denny Thomas in Hong Kong; Editing by Ed Davies and Editing by Vinu Pilakkott)