TORONTO (miningweekly.com) – Canadian base metals miner Hudbay Minerals on Friday extended its C$450-million takeover bid for project developer Augusta Resource Corp to May 27.

The offer was due to expire on Friday.

Hudbay said that it continued to monitor developments regarding Augusta's applications for permits required for its flagship Rosemont copper project, near Tucson, Arizona.

The Toronto-based company said that it was assessing the potential implications of a letter it alleged the US Army Corps of Engineers (USACE) sent to Augusta on Tuesday, in which it advised Augusta that its proposed damage control plan regarding its Clean Water Act Section 404 permit application was inadequate and that the USACE’s staff was now preparing a final permit decision.

Augusta did not issue a statement regarding the alleged letter, nor did it respond to Hudbay extending the offer.

Hudbay, which has applied to the British Columbia Securities Commission (BCSC) to block the Augusta shareholder rights plan, in March waived a condition of the offer that two-thirds of Augusta’s shares needed to be tendered for the deal to close.

The extension followed a ruling by the BCSC last week that it would cease trade Augusta’s shareholder rights plan, or ‘poison pill’, on July 15, but only if Hudbay extended its offer to July 16 and if it extended the offer for another ten days if any shares were taken up.

Augusta shareholders last Friday voted in favour of keeping the rights plan in place in a bid to thwart Hudbay’s takeover ambitions. Augusta’s poison pill was put in place in April last year, at a time when Hudbay was aggressively buying Augusta shares.

The BCSC ruling gives Augusta more time to look for alternative bidders. The company recently revealed that it had signed confidentiality agreements with ten potential suitors under its strategic review process.