Hecla Mining Co. (NYSE: HL) has agreed to acquire Mines Management, Inc. (NYSE MKT: MGN, TSX: MGT), the companies report. Under the deal, each common share of Mines Management would be exchanged for 0.2218 of a share of Hecla. This represents a 41% premium to Mines Management, using both companies’ 10-day volume weighted average price on Friday, the companies say. The transaction is expected to close in the third quarter and is subject to approval by Mines Management shareholders and other closing conditions. Hecla says that after closing, it intends to advance the evaluation of Mine Management’s Montanore project, which is located in northwest Montana and considered one of the largest undeveloped silver and copper deposits in North America. The project is approximately 10 miles from Hecla’s Rock Creek project and 50 miles north of Hecla’s Lucky Friday Mine in Idaho. “Hecla is the logical company to move Montanore forward, with its close proximity to Rock Creek, as well as its similar geology and scale,” says Phillips S. Baker, Jr., Hecla’s president and chief executive officer.