LONDON - Glencore executives have met or spoken with some 120 Teck Resources shareholders during a short visit to Toronto to try to win support for the company's takeover bid rather than an internal overhaul, a source familiar with the situation said.

Glencore made its $22.5-billion all-share offer as Teck's own plan to spin off its metallurgical coal business and focus on copper and zinc nears an April 26 vote.

Glencore CEO Gary Nagle flew to Canada to meet shareholders last Thursday, after earlier in the week revising the unsolicited bid to include up to $8.2 billion in cash, which Teck's board rejected as "largely unchanged".

The Swiss mining company would instead combine and spin off its thermal coal unit and Teck's steelmaking coal business.

Glencore declined to comment.

"We continue to engage extensively with our shareholders and believe that they recognize that Teck will be in a far better position to create value with a larger pool of interested parties after separation, and will support Teck's proposal," a spokesperson for Teck said in an email.

Teck also said that its biggest public shareholder China Investment Corporation (CIC) has not met with Glencore and that media reports that CIC was in favour of Glencore's proposed merger are false.

A wave of buyout offers for mines and mining companies is widely expected in coming months as demand increases for copper and other green energy transition minerals.

Shareholders have told Reuters that Glencore's offer is too low for them to reject Teck's restructuring plan or ask for a delay to the vote, while analysts expected the Swiss company to dig deeper into its pocket.

"If they were to increase the bid, then there is going to be a lot of pressure on Teck to delay their vote and to engage," said Ben Cleary, portfolio manager at Tribeca Global Natural Resources Fund.

Glencore's initial bid represented a 20% premium to Teck's closing stock price on March 26, when it was made privately.

JP Morgan analysts said in a note on Monday that Glencore could pay as much as $27.2-billion.

Teck has said it would explore a corporate transaction or partnership post separation, while sources said on Monday that the company has had approaches from more than six mining companies interested in its prized metals business.