VANCOUVER - First Quantum Minerals Ltd. (TSX:FM) said Wednesday it was standing pat with its $5.1-billion takeover offer for Inmet Mining Corp. (TSX:IMN) after taking an inside look at the company's books, but extended the bid to March 11.

"We valued the opportunity provided to us by the Inmet board for a Cobre Panama site tour and to conduct a detailed due diligence review, including having full access to key personnel and to Inmet's virtual data room," First Quantum chairman and chief executive Philip Pascall said.

"Following such access and having largely concluded our detailed review of Inmet's business, we have reconfirmed our offer to the Inmet board."

First Quantum's offer for Inmet was set to expire Wednesday. However, it extended the stock-and-cash proposal, which is valued at $72 per share, as it waits for approval under the Investment Canada Act.

Inmet's board has rejected the offer and recommended shareholders reject the bid, but has waived the application of a shareholder rights plan after a review of strategic alternatives.

Inmet has mining operations in Turkey, Spain and Finland, along with an 80 per cent interest in Cobre Panama, a development property in Panama currently in construction.