[ 3 ] Maturi Deposit tonnages do not include 139 million tons of mineralized material excluded from the underground resource in a safety pillar. [ 4 ] CIM Definition Standards (2010) were followed for Mineral Resource estimation and classification. [ 5 ] TPM is defined as Au + Pt + Pd.
Table 6 - SPRUCE ROAD DEPOSIT INFERRED MINERAL RESOURCE
Spruce Road Deposit Inferred Mineral Resource Cu % Million Cu Ni cut-off Tons % % 0.2 674 0.38 0.14 0.3 480 0.43 0.16 0.4 254 0.50 0.18 0.5 101 0.57 0.21 0.6 24 0.66 0.24
Exploration Target Area Tonnage and Grade Ranges
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. 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.Maturi 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