(Adds details, background on Lundin's previous bid)

July 16 (Reuters) - Canada's Lundin Mining Corp said on Monday it plans to make an offer to buy base metals company Nevsun Resources Ltd for about C$1.4 billion ($1.07 billion), its second proposal in three months.

Lundin offered C$4.75 per share, a premium of 12.8 percent to Nevsun's closing price of C$4.21 on Monday.

Cash-rich Lundin has been eyeing Nevsun's large high-grade Timok copper project in Serbia and its Bisha copper and zinc mine in Eritrea, in a partnership with Euro Sun Mining Inc .

Together the two companies proposed to buy Nevsun outright in May for C$1.5 billion, but were rejected by the company saying the price was too low and the deal had a "problematic structure".

"Our offer will represent the clearest path for Lundin Mining to acquire the Timok project and for Nevsun shareholders to realize on the value of their investment," Paul Conibear, chief executive officer of Lundin, said on Monday.

Nevsun has been seen as an attractive asset, with bankers and analysts telling Reuters in June that global miner Rio Tinto could also be a potential suitor for the Vancouver-based company.

Toronto-based Lundin produces copper, zinc and nickel from mines in Americas, Portugal and Sweden. The company said it might pull the offer if Nevsun implemented or attempted to implement any defensive tactics.

TD Securities and GMP Securities are acting as financial advisers to Lundin and Cassels Brock & Blackwell LLP and Paul, Weiss, Rifkind, Wharton & Garrison LLP are its legal advisers. ($1 = C$1.31) (Reporting by Anirban Paul in Bengaluru)