Similar to the June 2012 interim report, AMEC has again highlighted additional potential resources outside of the three mineral resources which occur on an additional 12% of the footprint of the Twin Metals Minnesota property. In addition to the TMM global resource, Exploration Targets have been outlined for four areas surrounding and adjacent to the Maturi and Birch Lake deposits. The grade and tonnage ranges of the four exploration targets are based on limited drill hole results. For the Maturi North and South targets, and the Birch Lake target, the target grade ranges and tonnage ranges were based on estimated blocks within the model above a 0.3% Cu cut-off grade that were not classified as either Indicated or Inferred, and applying a ±20% variance to the tonnages and grades to the estimates. The Maturi West exploration target was based on statistical analysis of limited drilling grades and thickness of intercepts at a 0.30% Cu cut-off.
The potential quantity and grade of the Exploration Targets are conceptual in nature, and there has been insufficient exploration to define the target as a mineral resource, and it is uncertain if further exploration will result in the target being delineated as a mineral resource.
The area inside the Maturi model perimeter surrounding the boundary of the Mineral Resource estimate was divided into two exploration targets, Maturi North and Maturi South. An additional exploration target, Maturi West, lies outside and to the west of the current model area. The tonnage and grades of the Maturi North exploration target could range from 290 to 435 million tons grading 0.41 to 0.61% Cu, 0.14 to 0.21 %Ni, 0.10 to 0.14 ppm Pt, 0.24 to 0.34 ppm Pd, and 0.07 to 0.07 ppm Au. The tonnage and grades of the Maturi South exploration target could range from 330 to 500 million tons grading 0.42 to 0.62 %Cu, 0.13 to 0.19 %Ni, 0.14 to 0.21 ppm Pt, 0.31 to 0.45 ppm Pd, and 0.07 to 0.10 ppm Au. The tonnage and grades of the Maturi West exploration target could range from 600 to 980 million tons grading 0.41 to 0.52 %Cu, 0.15 to 0.18 %Ni, 0.10 to 0.14 ppm Pt, 0.27 to 0.31 ppm Pd, and 0.07 to 0.07 ppm Au. The ranges of PGE values stated for Maturi West are based on regression formulas.Birch Lake