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VANCOUVER,
BRITISH COLUMBIA--(Marketwire - May 3, 2010) - Imperial Metals
Corporation (TSX:III). A recently completed mineral resource estimate
taking into account the 22 holes drilled by Imperial since its
acquisition of the Red Chris copper/gold project in northwest British
Columbia has added 1.29 billion pounds copper and 2.73 million ounces
gold to measured and indicated resources, and 1.37 billion pounds
copper and 2.54 million ounces gold to the inferred resources, at a
0.3% copper cut-off grade. Metallurgical testwork has confirmed
improved metal recoveries at depth from the higher gold and copper
grades found there.
At the 0.3% copper cut-off grade used for comparative purposes, the
revised resource estimate represents a 31% tonnage increase in the measured
and indicated category and an 89% tonnage increase in the inferred
category over the previous 2005 resource estimate. The copper and gold
grades in the measured and indicated category at the 0.3% copper
cut-off grade are also significantly higher, with copper grades
increasing from 0.46% to 0.54%, and gold grades increasing from 0.37 to
0.55 grams per tonne.
The higher grades discovered in the deeper drilling of the East zone
have yielded an even more dramatic increase in the resource at higher
cut-off grades. The measured and indicated resource at a 0.6% copper
cut-off grade increased from 35.1 million tonnes grading 0.82% copper
and 0.72 g/t gold to 86.96 million tonnes grading 0.88% copper and 1.11
g/t gold, representing a 148% increase in tonnage, a 7% increase in
copper grade and a 55% increase in gold grade. The key metal and
mineralogy changes observed at depth are increased gold and copper
grades, increased the gold to copper ratio, increased distribution and
occurrence of bornite, and reduced pyrite content.
Diamond drilling carried out by Imperial since acquiring the project in
2007 has extended the higher grade East zone to a depth of
approximately one kilometre, more than double the depth of past
drilling. This drilling has substantially increased the amount of
contained metal, confirming more drilling is required to upgrade
inferred resources to measured and indicated, and to further test the
extent of the deposit at depth. Exploration drilling is underway with
three drills and a fourth rig being mobilized to the site.
The estimate was prepared internally by Art Frye, Mine Operations
Manager for the Mount Polley mine, and by Greg Gillstrom P.Eng, Senior
Geological Engineer with Imperial Metals Corporation, who is designated
as the "Qualified Person" as defined under 43-101 for the
resource calculation. Mr. Gillstrom and Mr. Frye have reviewed the
contents of this release. A technical report providing details of the
estimate will be filed on SEDAR (www.sedar.com) within 30 days.
Imperial is preparing an update of the 2005 Feasibility Study for the
development of the Red Chris project. The Company has initiated the
project Mines Act permitting for the development of Red Chris with the
Northwest Mine Development Review Committee ("NWMDRC")
Northwest Mine Development.
Mineral resources are reported at various cut-off grades as presented
in the following table.
RED CHRIS DEPOSIT MINERAL RESOURCES - MAY 2010 ------------------------------------------------------------------------- MEASURED + INDICATED MINERAL RESOURCES ------------------------------------------------------------------------- Cut-off Tonnes Lbs Cu Oz Gold Cu% X 1,000 Cu% Au g/t CuEq% X 1,000 x 1,000 ------------------------------------------------------------------------- greater 619,417 0.38 0.36 0.534 5,139,790 7,162 than or =0.10 greater 489,151 0.43 0.42 0.618 4,674,389 6,634 than or =0.20 greater 312,571 0.54 0.55 0.781 3,710,414 5,564 than or =0.30 greater 189,526 0.66 0.74 0.986 2,775,182 4,484 than or =0.40 greater 125,310 0.78 0.93 1.182 2,147,043 3,728 than or =0.50 greater 86,957 0.88 1.11 1.367 1,685,773 3,115 than or =0.60 greater 57,585 1.00 1.34 1.584 1,267,272 2,479 than or =0.70 greater 39,207 1.12 1.56 1.798 965,359 1,961 than or =0.80 greater 27,299 1.24 1.78 2.013 744,212 1,558 than or =0.90 greater 20,083 1.34 1.96 2.199 593,780 1,266 than or =1.00 greater 15,633 1.42 2.08 2.334 491,073 1,045 than or =1.10 greater 12,072 1.51 2.21 2.474 401,064 858 than or =1.20 greater 8,973 1.60 2.39 2.644 316,025 690 than or =1.30 greater 6,568 1.69 2.51 2.787 244,377 531 than or =1.40 greater 4,806 1.78 2.69 2.951 188,175 415 than or =1.50 ------------------------------------------------------------------------- ------------------------------------------------------------------------- INFERRED MINERAL RESOURCES ------------------------------------------------------------------------- Cut-off Tonnes Lbs Cu Oz Gold Cu% X 1,000 Cu% Au g/t CuEq% X 1,000 X 1,000 ------------------------------------------------------------------------- greater 619,129 0.30 0.32 0.443 4,120,730 6,429 than or =0.10 greater 437,939 0.36 0.39 0.531 3,497,936 5,433 than or =0.20 greater 237,701 0.46 0.50 0.675 2,396,943 3,794 than or =0.30 greater 105,613 0.60 0.69 0.901 1,398,864 2,332 than or =0.40 greater 60,326 0.72 0.87 1.101 957,825 1,687 than or =0.50 greater 39,197 0.81 1.02 1.257 702,112 1,282 than or =0.60 greater 22,470 0.94 1.19 1.460 464,170 863 than or =0.70 greater 14,317 1.05 1.37 1.648 331,485 629 than or =0.80 greater 8,814 1.18 1.56 1.859 228,447 442 than or =0.90 greater 6,388 1.26 1.69 2.002 177,860 347 than or =1.00 greater 4,561 1.35 1.79 2.137 135,958 263 than or =1.10 greater 3,814 1.39 1.84 2.195 116,922 225 than or =1.20 greater 2,387 1.47 1.92 2.312 77,533 147 than or =1.30 greater 1,393 1.56 1.95 2.418 48,047 87 than or =1.40 greater 796 1.65 2.02 2.535 28,948 52 than or =1.50 ------------------------------------------------------------------------- ------------------------------------------------------------------------- MEASURED MINERAL RESOURCES ------------------------------------------------------------------------- Cut-off Tonnes Lbs Cu Oz Gold Cu% X 1,000 Cu% Au g/t CuEq% X 1,000 X 1,000 ------------------------------------------------------------------------- greater 534,267 0.38 0.37 0.544 4,514,679 6,311 than or =0.10 greater 424,693 0.44 0.43 0.628 4,124,308 5,863 than or =0.20 greater 277,190 0.54 0.56 0.787 3,318,846 4,962 than or =0.30 greater 171,002 0.67 0.73 0.986 2,510,390 4,023 than or =0.40 greater 113,545 0.78 0.92 1.180 1,948,007 3,350 than or =0.50 greater 78,659 0.88 1.11 1.366 1,528,268 2,800 than or =0.60 greater 52,028 1.00 1.34 1.586 1,148,837 2,234 than or =0.70 greater 35,491 1.12 1.55 1.801 877,028 1,773 than or =0.80 greater 24,663 1.24 1.78 2.022 675,946 1,411 than or =0.90 greater 18,242 1.35 1.97 2.210 542,129 1,156 than or =1.00 greater 14,224 1.43 2.09 2.349 449,268 958 than or =1.10 greater 11,012 1.52 2.23 2.493 368,075 791 than or =1.20 greater 8,144 1.61 2.43 2.674 289,485 635 than or =1.30 greater 6,038 1.70 2.54 2.816 226,697 494 than or =1.40 greater 4,558 1.79 2.71 2.973 179,436 398 than or =1.50 ------------------------------------------------------------------------- ------------------------------------------------------------------------- INDICATED MINERAL RESOURCES ------------------------------------------------------------------------- Cut-off Tonnes Lbs Cu Oz Gold Cu% X 1,000 Cu% Au g/t CuEq% X 1,000 X 1,000 ------------------------------------------------------------------------- greater 85,150 0.33 0.31 0.469 625,112 851 than or =0.10 greater 64,458 0.39 0.37 0.550 550,081 771 than or =0.20 greater 35,381 0.50 0.53 0.733 391,568 602 than or =0.30 greater 18,524 0.65 0.77 0.987 264,792 461 than or =0.40 greater 11,765 0.77 1.00 1.204 199,036 377 than or =0.50 greater 8,299 0.86 1.18 1.377 157,505 315 than or =0.60 greater 5,558 0.97 1.37 1.568 118,435 246 than or =0.70 greater 3,716 1.08 1.58 1.769 88,331 188 than or =0.80 greater 2,637 1.17 1.74 1.934 68,266 147 than or =0.90 greater 1,841 1.27 1.86 2.088 51,651 110 than or =1.00 greater 1,409 1.35 1.93 2.188 41,806 87 than or =1.10 greater 1,060 1.41 1.98 2.276 32,989 67 than or =1.20 greater 828 1.45 2.05 2.350 26,540 55 than or =1.30 greater 530 1.51 2.15 2.455 17,680 37 than or =1.40 greater 248 1.60 2.20 2.558 8,740 18 than or =1.50 ------------------------------------------------------------------------- A copper only cut-off was used in this study to match the historic study; future studies will use a CuEq (copper equivalency) cut-off. The copper equivalent column on the resource table was calculated using prices of copper ($3.00/lb) and gold ($900/oz) and not including any metallurgical parameters to show a copper equivalent value for the resource.
At
year end 2009, two composite samples of deep East zone mineralization
were submitted to G&T Metallurgical Services for testing to assess
the mineralogical and metallurgical response of deeper East zone
mineralization. The testwork conformed to the previously developed
process for treating Red Chris ores. The two samples were derived from
recent drilling. The first, "High Au to Cu" was made up from
high gold to copper ratio intervals and the second, "High
Bornite" was from intervals with a high percentage bornite (a
copper sulphide mineral that is 66% copper). Both samples had high
values of copper and gold and relatively low ratios of pyrite to copper
sulphides compared to previously tested East zone samples.
The High Au to Cu East zone composite exhibited almost perfect copper
metallurgical performance with 97-98% recovered into rougher
concentrate, along with 91-93% of the gold. Both copper and gold
rougher flotation performances were well above average for deposits of
this type. Overall the results, including cleaning, were remarkably
high with 96% of the copper recovered into a concentrate grading about
33% copper. Similarly, 88% of the gold was recovered into the copper
concentrate grading about 50 grams per tonne gold.
The High Bornite flotation testing resulted in recoveries of 93-95%
copper and an average of 88% gold into the rougher concentrate. After
cleaning the rougher concentrates about 90% of the copper in the feed
was recovered into a concentrate grading about 45% copper. Gold
performance following cleaning was variable, but on average about 75%
of the gold was recovered into the copper concentrate grading about 60
grams per tonne gold.
The observed performance was superior to results achieved on previously
tested East zone samples. The excellent response of these composite
samples is attributable to the higher grade of copper and gold, lower
pyrite content and more favorable fragmentation properties. The
testwork employed the previously developed Red Chris flowsheet,
designed for lower grade ores containing considerably more pyrite. The
flowsheet could likely be optimized to reduce operating costs when
treating mineralization similar to the composites tested in this
program. Adopting coarser primary and regrinding sizes, and lower pulp
pH could reduce costs, with negligible effect on metallurgical
performance.
The Red Chris project is located in northwest British Columbia, and
lies at an elevation of 1,500 metres above sea-level on a plateau with
topography and climate favorable to mining operations. Red Chris is 310
kilometres from tidewater at the port of Stewart. Access to the
property from pavement at Highway 37 is six kilometres along the Ealue
Lake Road, and 17 kilometres along the Red Chris access trail.
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