HudBay Minerals announced on Feb. 9 that will make an offer of about C$360 million (US$325 million) to acquire the 84 percent stake of August Resources Corp. that is does not already own.

HudBay has base-metal mining operations and development projects in Manitoba and Peru and owns a 16 percent stake of Vancouver-based Augusta, which is developing the Rosemont copper project near Tucson, Ariz. The project has an estimated mine life of more than 21 years with 5.9 billion lbs of copper reserves and 194 million lbs of molybdenum reserves, according to Augusta's web site.

"Since our initial investment in Augusta in 2010, we have been excited about the potential of the Rosemont project. We view the Rosemont project as an attractive complement to our existing portfolio of high quality, long-life assets that fits well with our construction timeline at Constancia," said David Garofalo, president and chief executive officer in a statement posted on HudBay Minerals website. "The transaction will be accretive to Hudbay shareholders on key per share metrics and both Hudbay and Augusta shareholders will benefit from our ability to leverage our 87 year history of successful project execution and operations."

In a release, Augusta said its board will meet this week to discuss HudBay's plan.

HudBay's hostile bid comes at a time when many mining stocks are trading at relatively low levels as commodity prices have weakened amid concerns over slowing economic growth in China and other emerging economies that had fueled a big part of a now ended decade-long commodity boom. That has made some mining companies susceptible to hostile bids, The Wall Street Journal reported.

In January, Canadian gold miner Goldcorp Inc. launched a C$2.8 billion hostile bid for Quebec-based Osisko Mining Corp., which later that month launched a court battle to try to block the bid.

HudBay said it is offering 0.315 of a Hudbay common share for each Augusta common share, worth about C$2.96 per Augusta common share, based on HudBay's closing share price on the Toronto Stock Exchange Friday. Using the 20-day volume-weighted average share prices of HudBay and Augusta on the Toronto Stock Exchange for the period ended on Feb. 7, HudBay said the offer represents a premium of 62 percent.

The bid is open to March 19, HudBay said.