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VANCOUVER,
BRITISH COLUMBIA--(Marketwire
- March 30, 2009) - Imperial Metals Corporation (TSX:III)
has updated the mineral reserve and mineral resource estimates for the Mount Polley
and Huckleberry mines.
Mount Polley Updated Mineral Reserve and
Mineral Resource Estimate
The reserve and resource estimate for Mount Polley has been
updated as of January 1, 2009. The current estimate incorporates open
pit mining of the Southeast, C2, Pond and Springer zones, in addition
to completing the current Wight pit in the Northeast zone, and reflects
twelve months of mine production since the January 1, 2008 estimate. As
of January 1, 2009 total Mount Polley
reserves are 46.2 million tonnes of 0.34% copper, 0.29 g/t gold and
0.95 g/t silver, compared to 55.6 million tonnes of 0.36% copper, 0.30
g/t gold and 0.66 g/t silver at January 1, 2008. The Bell pit was completed in 2008, and
the Wight pit will be completed in the second quarter of 2009. Exploration
in 2008 brought the Pond zone into a minable reserve scheduled for open
pit mining in the third quarter of 2009 subject to obtaining required
approvals. In total 6.9 million tonnes were mined in 2008. The current
mine life for Mount
Polley
is to the fourth quarter of 2015. Drilling continues to expand the
resources on the site, with 113.0 million tonnes of mineral resources
identified in the Measured and Indicated category and 29.0 million
tonnes of mineral resources identified in the Inferred category, in
addition to the reserves below.
--------------------------------------------------------------------------- Mount Polley Mine Proven and Probable Reserves --------------------------------------------------------------------------- Grade Contained Metal ------------------- --------------------------- Copper Gold Silver Strip- Copper Gold Silver (lb) (oz) (oz) ping Zone/Pit Tonnes Ore % g/t g/t 000,000's 000's 000's Ratio --------------------------------------------------------------------------- Wight 785,362 0.73 0.209 5.573 12.64 5.28 140.72 0.39 Springer 39,233,777 0.336 0.27 0.716 290.62 340.58 903.16 2.13 Pond 1,372,216 0.476 0.27 6.898 14.40 11.91 304.32 3.5 Southeast 1,752,306 0.274 0.513 1.11 10.58 28.90 62.54 1.39 C2 3,006,923 0.295 0.446 n/a(i) 19.56 43.12 n/a(i) 4.62 --------------------------------------------------------------------------- Total 46,150,584 0.342 0.290 0.951 347.80 429.78 1410.74 --------------------------------------------------------------------------- n/a(i) - silver assay values not significant in this zone
Reserve
Calculation Parameters
The parameters used in this updated resource are based on updated pit
designs and the current Mount
Polley
production schedule. The ultimate pit designs were based on US$1.75
copper, US$800.00 gold, US$10.00 silver and $1.25 CDN/US exchange rate.
The economic mineral reserves and resources at Mount Polley mine were
calculated as follows:
- A 3D block model was constructed using Minesight
Mining Software.
- The property was zoned based on geological zones,
the blocks and drill holes were then coded to reflect the zones.
- The drill holes were composited to 5 metre down the hole composites.
- Mineralized zones were identified within the geological zones, by kriging an indicator to identify the blocks that
have a high probability of having greater than a 0.15% copper grade.
- The drill hole composites were then coded to
match the indicator codes in the block model.
- Outlier grades were capped, and variograms
for Cu, Au, Ag and Fe in each zone were generated.
- Grades were kriged into the block model,
using zone and indicator matching.
- An oxide ratio number for each block was interpolated using an ID3
method, with zone and indicator matching. The oxide ratio number is
used in the mill recovery formula.
- The mill recoverable grades were calculated using formulas based on
historic recoveries as well as on and off site metallurgical test work.
- A dollar value was calculated for each block based on the metals
prices, US/Can Exchange Rate, and mining, shipping and smelting costs.
- Lerchs-Grossman pit optimization software
was used to identify economic pit shell based on the above economic
parameters. Pit designs were created using the economic pit shells and
design parameters from Golder Geotechnical
Consultants of Vancouver.
--------------------------------------------------------------------------- Resource by Zone (i) (resource values based on 0.3 Copper Equivalent Cut-Off) --------------------------------------------------------------------------- Grade Contained Metal --------------------------- -------------------------- Copper Copper Gold Silver Equiv Copper Gold Silver (lb) (oz) (oz) Zone Tonnes Ore (i)% % g/t g/t 000,000's 000's 000's --------------------------------------------------------------------------- Northeast (ii) & Boundary --------------------------------------------------------------------------- Measured 19,631,561 0.774 0.580 0.229 4.077 251.02 144.54 2573.28 Indicated 2,666,499 0.677 0.464 0.267 3.281 27.28 22.89 281.28 Inferred 2,366,199 0.500 0.372 0.156 2.301 19.41 11.87 175.05 --------------------------------------------------------------------------- Zuke (iii) see note below --------------------------------------------------------------------------- Measured (iii) (iii) (iii) (iii) (iii) (iii) (iii) (iii) Indicated (iii) (iii) (iii) (iii) (iii) (iii) (iii) (iii) Inferred (iii) (iii) (iii) (iii) (iii) (iii) (iii) (iii) --------------------------------------------------------------------------- Bell --------------------------------------------------------------------------- Measured 9,562,373 0.420 0.233 0.238 n/a(i) 49.12 73.17 n/a(i) Indicated 976,160 0.376 0.227 0.190 n/a(i) 4.89 5.96 n/a(i) Inferred 828,312 0.372 0.236 0.174 n/a(i) 4.31 4.63 n/a(i) --------------------------------------------------------------------------- Springer --------------------------------------------------------------------------- Measured 18,437,736 0.592 0.359 0.297 0.709 145.93 176.06 420.29 Indicated 26,536,116 0.538 0.300 0.302 0.643 175.50 257.65 548.58 Inferred 25,475,566 0.540 0.290 0.316 0.561 162.87 258.82 459.49 --------------------------------------------------------------------------- C2 --------------------------------------------------------------------------- Measured 5,352,649 0.490 0.237 0.363 n/a(i) 27.97 62.47 n/a(i) Indicated 4,045,493 0.488 0.240 0.356 n/a(i) 21.40 46.30 n/a(i) --------------------------------------------------------------------------- Southeast --------------------------------------------------------------------------- Measured 18,421,459 0.515 0.180 0.414 1.052 73.02 245.20 623.06 Indicated 5,306,026 0.424 0.159 0.325 0.978 18.62 55.44 166.84 --------------------------------------------------------------------------- Pond --------------------------------------------------------------------------- Measured 1,477,694 0.654 0.379 0.324 5.774 12.34 15.39 274.32 Indicated 630,108 0.502 0.268 0.257 6.279 3.72 5.21 127.20 --------------------------------------------------------------------------- Total Resource --------------------------------------------------------------------------- Measured/ Indi- cated 113,043,874 0.568 0.325 0.305 1.380 810.81 1110.28 5014.84 Inferred 28,670,077 0.532 0.295 0.299 0.688 186.59 275.32 634.54 --------------------------------------------------------------------------- n/a(i) silver assay values not significant in this zone (i) Proven and Probable Reserves are not included in these resource values (ii) Northeast Zone contains the Wight Pit (iii) The Zuke Zone is a high grade underground target now being delineated south of the Boundary Zone. Some assay results from 2008 and 2009 drilling in the Zuke Zone are pending. A resource estimate for this new zone will be available later this summer. ------------------------------------------------------------------- Copper Equivalent Calculation by Zone (resource values based on 0.3 Copper Equivalent Cut-Off) ------------------------------------------------------------------- Northeast(i) EqCu% equals Copper + Gold / 1.44 + Silver / 116 Pond EqCu% equals Copper + Gold / 1.44 + Silver / 116 Springer EqCu% equals Copper + Gold / 1.27 + Silver / 116 C2 EqCu% equals Copper + Gold / 1.27 Southeast EqCu% equals Copper + Gold / 1.27 + Silver / 116 ------------------------------------------------------------------- (i) Northeast Zone contains the Wight Pit
Resource
values were identified by summing all blocks that fall outside of the
economic pit and having a block grade greater than 0.30 copper equivalent. The copper equivalent was calculated
using relative recovery and metal price for copper, gold and silver. The
resources were classified as inferred, indicated and measured based on
the following three items; minimum number of drill holes used in the
estimate, minimum number of composites, and the maximum distance to the
nearest composite.
------------------------------------------------------------------- Resource Calculation Parameters ------------------------------------------------------------------- Resource Min. # of Holes Min. # of Max. Distance to Classification Used for Estimate Composites Nearest Composite ------------------------------------------------------------------- Inferred 1 3.000 60m Indicated 2 3.000 50m Measured 3 5.000 25m -------------------------------------------------------------------
The
ore reserves and resources were calculated and verified by Art Frye,
Manager of Mining, Mount Polley Mining
Corporation and Greg Gillstrom, P. Eng.,
Geological Engineer, the designated Qualified Person as defined by
National Instrument 43-101.
Huckleberry Updated Mineral Reserve and Mineral Resource Estimate
The Main Zone Extension is the only pit actively operating at
Huckleberry. On December 31, 2008 the mineral reserve of the Main Zone
Extension pit was calculated at a cut-off grade of 0.224%. Probable
reserves at December 31, 2008 were prepared under the supervision of
Kent Christensen, P.Eng., Huckleberry Mine Chief Mine Engineer, designated
as the Qualified Person for this purpose.
------------------------------------------------------------------- Huckleberry Mine Proven and Probable Reserves ------------------------------------------------------------------- Ore (tonnes) Copper(%) Moly(%) Strip Ratio ------------------------------------------------------------------- Main Zone Extension 8,368,000 0.362 0.005 0.37:1 -------------------------------------------------------------------
Prices used in the calculation of the
Huckleberry reserves were US$1.63/lb copper, US$550.00/oz gold,
US$8.50/oz silver, US$7.50/lb molybdenum and an exchange rate of $1.15
CDN/US.
The current mine life for Huckleberry is 2010. Exploration will
continue in 2009 to find additional reserves.
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