Twin Metals Minnesota LLC (sometimes herein referred to as "TMM" or "Twin Metals") is the joint venture company between Duluth Metals Limited (60% ownership interest) and Antofagasta plc (40% ownership interest). In 2011, Twin Metals Minnesota LLC acquired Franconia Minerals Corporation. Franconia`s principal assets are a 70% interest in the Birch Lake, "old Maturi" (not including former Nokomis property) and Spruce Road deposits through the Birch Lake Joint Venture, with Beaver Bay Resources owning the remaining 30%. Franconia announced in November, 2010 its intention to increase its ownership at the Birch Lake Joint Venture to 82% upon commencement of production. All of the forgoing Indicated and Inferred Mineral Resources, and Exploration Target tonnages are expressed as a 100% ownership position.
The Mineral Resource estimate for the Maturi deposit incorporates assay data from 444 drill holes and 154 wedge off-set holes totalling 1,328,000 feet drilled on the Maturi deposit between 2006 and 2012, in addition to information from 99 legacy holes also in the geologic data base. The Birch Lake deposit resource estimate incorporates assay data from 97 drill holes and 146 wedge off-set holes totalling 297,000 feet drilled between 2000 and 2012, and information from an additional 17 legacy drill holes and 8 wedge off-set holes. The Spruce Road deposit resource estimate incorporates assay data from 210 legacy holes. The effective date of the mineral resource estimate is 15 September 2012.
Figure 3 below is a map showing the Indicated and Inferred boundaries and the Exploration Target Areas which can be found as part of this press release on the Company website at http://www.duluthmetals.com.
The December 2012 Resource Estimates for the Maturi, Birch Lake and Spruce Road deposits are based on a 0.3% copper cut-off grade to define the resource model. Based on AMEC`s review of metal prices, process recoveries, refining costs and underground mine operating costs likely to apply at the Twin Metals site, the 0.3% copper cut-off grade (highlighted) is considered the base case for the statement of Indicated and Inferred Mineral Resources at this time. The estimates at the cut-off grades higher and lower than the base case are provided to show sensitivity of the estimates to cut-off grade.Detailed Resource Tabulations