Rio Tinto names Shell’s Katie Jackson as new copper chief
Jackson, who is the current president of National Grid Ventures, an energy group, joins Rio Tinto on September 1.
MONTREAL, QUEBEC–(Marketwire -11/07/11)- Osisko Mining Corporation (TSX: OSK.TO – News)(Frankfurt: EWX.F – News) is pleased to provide an updated inferred resource estimate for its 100%-owned Hammond Reef gold project, located near Atikokan, Ontario. New drilling by Osisko and Brett Resources from January 2010 to July 2011 (approximately 300,000 metres) has significantly increased the size of the deposit. This update reports both global and in-pit resources in the inferred category. Additional drilling subsequent to July 2011 is anticipated to allow for the upgrade of the entire in-pit deposit to Measured and Indicated category by Q1 2012.
Key points:
-- Global Inferred resource currently stands at 10.52 million ounces gold (based on 0.30 g/t Au lower cut-off), an increase of 65% or 4.16 million new ounces from the total resources previously released by Brett Resources in 2009. -- The in-pit inferred resource is now 6.86 million ounces at a diluted grade of 0.63 grams per tonne gold, based on a Whittle-optimized pit shell using a gold price of US$1200 per ounce, a corresponding lower cut-off grade of 0.28 grams per tonne gold and a waste/ore strip ratio of 1.25. This represents an increase of 25% or 1.36 million ounces gold above the previous in-pit resource estimate released by Brett resources in 2009. -- At US$1800 per ounce gold, the in-pit inferred resource increases to 10.8 million ounces at an average grade of 0.50 grams per tonne gold. -- At a conservative gold price of US$1000, the in-pit inferred resource is 5.32 million ounces at a diluted grade 0.71 grams per tonne gold, with a low waste/ore strip ratio of 0.96, which is better than the industry average. -- The A (Main) and Mitta Zones form a contiguous deposit, while the 41 Zone is separate. The system was modeled as two pits with a total strike length of 2500 metres (sections 870E to 3370E). Exploration drilling around the Mitta and A zones has been successful in extending the deposit in the down-dip (southeast) direction, to a maximum distance (along dip) of 850 metres. -- Although the entire resource in this update is reported in the inferred category, variography indicates that approximately 33 to 48 percent of the global resource (depending on cut-off grade) could presently be classified in the indicated category. Osisko will report upgraded (Measured and Indicated) resource categories in Q1 2012, upon the completion of a final 130,000 metres of planned definition drilling.
SGS Canada Inc. of Montreal, Quebec (“SGS”) are the independent resource estimate consultants who have authorized the release of the following estimates. The global Inferred resource is 10.52 million ounces of gold at an average undiluted grade of 0.62 g/t Au, based on a lower cut-off grade of 0.30 g/t Au. The table below summarizes the SGS estimates using variable lower cut-off grades:
Hammond Reef Global Inferred Resource Estimates --------------------------------------------- Grade (g/t) Tonnes (M) Cut-off Oz (M) (g/t) --------------------------------------------- 0.41 998.6 0.10 13.24 --------------------------------------------- 0.53 701.2 0.20 11.88 --------------------------------------------- 0.62 530.6 0.30 10.52 --------------------------------------------- 0.67 454.8 0.35 9.73 --------------------------------------------- 0.72 384.9 0.40 8.88 --------------------------------------------- 0.77 323.4 0.45 8.04 --------------------------------------------- 0.83 272.5 0.50 7.27 --------------------------------------------- 0.94 193.6 0.60 5.88 --------------------------------------------- 1.06 139.4 0.70 4.75 --------------------------------------------- 1.17 103.2 0.80 3.88 --------------------------------------------- 1.28 77.8 0.90 3.19 --------------------------------------------- 1.38 59.0 1.00 2.62 ---------------------------------------------
G Mining Services Inc. of Montreal, in collaboration with SGS, also estimated an in-pit inferred resource within a single Whittle-optimized pit shell using a base case gold price of US$1200 per ounce and a dilution factor of 5%. The in-pit inferred resource for the Hammond Reef gold deposit is 6.86 million ounces of gold at an average diluted grade of 0.63 g/t Au, based on a derived lower cut-off grade of 0.28 g/t Au. Sensitivity of the diluted in-pit inferred resource (based on minimum cut-off grade) to gold price is as follows:
-------------------------------------------------------------------- Strip Ratio Gold Price (US$) Grade (g/t) Tonnes (M) (Waste/Ore) Oz (M) -------------------------------------------------------------------- $600 0.96 89.12 1.69 2.76 -------------------------------------------------------------------- $700 0.87 126.03 1.29 3.54 -------------------------------------------------------------------- $800 0.81 160.12 1.12 4.16 -------------------------------------------------------------------- $900 0.75 199.75 1.01 4.81 -------------------------------------------------------------------- $1000 0.71 234.40 0.96 5.32 -------------------------------------------------------------------- $1100 0.67 263.24 0.91 5.70 -------------------------------------------------------------------- $1200 0.63 336.58 1.25 6.86 -------------------------------------------------------------------- $1300 0.60 413.13 1.43 7.96 -------------------------------------------------------------------- $1400 0.57 469.68 1.47 8.66 -------------------------------------------------------------------- $1500 0.55 536.12 1.58 9.51 -------------------------------------------------------------------- $1600 0.53 579.81 1.55 9.95 -------------------------------------------------------------------- $1700 0.52 630.77 1.63 10.54 -------------------------------------------------------------------- $1800 0.51 658.23 1.62 10.79 --------------------------------------------------------------------
The table below summarizes the undiluted in-pit estimates using variable lower cut-off grades:
Hammond Reef Undiluted Resource Estimates within US$1200 Whittle pit shell -------------------------------------------------- Inferred Resources -------------------------------------------------- Grade Tonnes (M) Cut-off (g/t) Oz (M) (g/t) -------------------------------------------------- 0.68 308.3 0.30 6.75 -------------------------------------------------- 0.77 245.3 0.40 6.05 -------------------------------------------------- 0.87 187.6 0.50 5.23 -------------------------------------------------- 0.97 142.1 0.60 4.43 -------------------------------------------------- 1.09 104.8 0.70 3.66 -------------------------------------------------- 1.18 82.3 0.80 3.11 -------------------------------------------------- 1.29 61.4 0.90 2.55 -------------------------------------------------- 1.38 48.3 1.00 2.15 --------------------------------------------------
Sean Roosen, President and CEO of Osisko, commented: “We are very pleased with Osisko’s first inferred resource estimate for the Hammond Reef Project, which has achieved a 65 percent increase, or an additional 4.16 ounces of gold in the global resource, with respect to the previous Brett Resources estimate. While there is no doubt that the resource has a lower overall grade than Canadian Malartic, an important point to note is that the new in-pit resource for Hammond Reef has a low strip ratio of 1.25 and is quite robust, as it is based on current processing and mining costs at Canadian Malartic, adjusted for higher electrical costs in Ontario.”
“Osisko completed 300,000 metres of diamond drilling in just over a year to get to today’s inferred resource numbers, a huge achievement in such a short period of time. By February 2012 we will have completed an additional 130,000 metres of drilling on a 50 x 25 metre grid to allow for the conversion of the entire in-pit resource to Indicated category. To convert approximately one-third of the resource to Measured category, we also plan to drill an additional 70,000 metres on a 25 x 25 metre grid. The next resource update, slated for the end of Q1 2012, will be followed by feasibility for Hammond Reef”.
Details on the parameters of the resource estimates are as follows:
-- The database comprised a total of 365,115 metres of drilling completed and assayed by Brett Resources and Osisko as of the end of July 2011 on a minimum 50 m x 25 metre grid. (All NQ core assays reported by Osisko were obtained by standard 50 g fire assaying-AA finish or gravimetric finish at ALS Chemex laboratories.) -- The database also comprised a total of 222,947 assays with an average of 1.49 metre per sample for a total of 332,250 assayed metres. -- The estimates were done using Ordinary Kriging (OK) interpolation as the geostatistical method based on 5.0 metre analytical composites. -- All estimates are based on a block dimension of 10 metres E, 10 metres N and 10 metres height with estimation parameters determined by variography. -- Geological interpretation identified a Main domain and several smaller domains (that surround the Main domain. The Main domain is a tabular zone that dips to the southeast and includes the A, Mitta and 41 zones on surface. The RAB zone was recognized as a separate domain that was ignored for the purposes of the in-pit resource estimate. -- Calculations are based on original samples capped to a maximum of 15 g/t Au for the Main domain. Capping was not necessary for the smaller domains. This resulted in an approximate 1.5 percent reduction in the overall gold content. All 5-metre composites are calculated based on cut original data. -- Tonnage estimates are based on a rock density of 2.75 tonnes/cubic metre for the altered tonalite host rock. -- The global resource estimates using the lower cut-off of 0.30 g/t Au is emphasized for reporting purposes as this is very close to the in-pit cut-off of 0.28 g/t Au estimated for the US$1200 Whittle shell. -- The US$1200 Whittle shell has approximate maximum dimensions of 2,500 metres in length, 1,050 metres in width and a vertical depth of 380 metres. -- The average gold recovery for this pit shell is 91.0%. Overall slope angles based on feasibility level geotechnical studies (including provisions for ramps) are between 41.3 and 50.3 degrees. Total ore-based cost is US $9.13 with reference mining cost of US $1.61 per tonne mined plus incremental depth costs of US$0.0338 per 10m bench. Strip ratio is 1.25 for the in-pit resource corresponding to a lower cut-off of 0.28 g/t Au.
Osisko Mining Corporation is currently running the Canadian Malartic gold mine in Quebec as a large-scale open pit, bulk-tonnage operation. The Canadian Malartic mine is slated to be one of the largest single gold producers in Canada when full capacity is achieved in 2012. The Company is well-funded and is carrying out aggressive exploration and project development elsewhere in Canada and Latin America.
Mr. Michel Dagbert, P. Eng. of SGS Canada Inc. (global resource estimate) and Mr. Louis-Pierre Gignac, P. Eng. of G Mining Services Inc. (Whittle-optimized in-pit resource estimate) are the Qualified Persons responsible for the technical information reported herein, including verification of the data disclosed. Mr. Robert Wares, P. Geo. and Executive Vice-President of Osisko, has also reviewed and approved the technical contents of this news release.
