Mines Management, Inc. (“MMI”) (NYSE-Amex:MGN) (TSX:MGT) has filed on SEDAR a Technical Report entitled “Technical Report: Preliminary Economic Assessment, Montanore Project, Montana, USA prepared for Mines Management Inc.” (“Technical Report”) dated February 3, 2011, in support of a Preliminary Economic Assessment (“PEA”) for the Company’s wholly owned Montanore Silver-Copper Project in compliance with Canadian National Instrument 43-101. (“NI 43-101”). The Technical Report was prepared by Mine and Quarry Engineering Services, Inc. of San Mateo, California (“MQes). MMI previously announced the PEA results set forth below on December 22, 2010.
A mine plan developed by MMI was audited by MQes. Cost estimates were developed by MQes. The mine plan is based on a measured and indicated mineral resource of 81.5 million short tons of material grading 2.04 ounces per short ton (“opt”) silver and 0.75% copper, and an inferred mineral resource of 35.0 million short tons grading 1.85 opt silver and 0.71% copper at a cutoff grade of 1.0 opt silver, previously reported in an NI 43-101 Technical Report dated October 2005 prepared by Mine Development Associates (“MDA”) of Reno, Nevada. MDA’s estimate reported by MMI of estimated mineralized material reported pursuant to U.S. Securities and Exchange Commission rules in its annual report on Form 10-K for the year ended December 31, 2009, remains unchanged.
The PEA indicates the potential for a financially robust underground mine utilizing conventional grinding and flotation processing techniques at a nominal throughput of 12,500 short tons per day (“st/d”). At a 5% discount rate, a silver price of US$15.00 per ounce (“oz”) and a copper price of US$3.10 per pound (“lb”), the project’s pre-tax Net Present Value (“NPV”) is indicated to be US$485 million with an internal rate of return (“IRR”) of 17.4% on an unleveraged 100% equity basis.
Using metals prices as of November 17, 2010, of US$25.65/oz. silver and US$3.72/lb. copper, the project indicated a pre-tax NPV of US$1.323 billion and IRR of 32.3%, at a 5% discount rate.