Northgate Minerals Announces Updated Resource Estimate for Kemess Underground
16.02.2011 | CNW
Indicated Resource Contains 2.6 Million Ounces of Gold and 860 Million Pounds of CopperVANCOUVER, Feb. 15 (CNW) - Northgate Minerals Corporation (TSX: NGX, NYSE Amex: NXG) is pleased to report an updated NI 43-101 compliant resource estimate for the Kemess Underground Project, located five kilometres ("km") north of the Kemess South mine and milling complex in north-central British Columbia. The updated resource estimate follows on the completion of a 30-hole infill diamond drill program at Kemess Underground in 2010.
Highlights
- Indicated Resource of 136.5 million tonnes ("Mt") containing 2.6 million ounces of gold and 860.6 million pounds of copper.
- Identified a 10.3 Mt, high-grade sector of the overall resource containing 450,000 ounces of gold and 119 million pounds of copper grading 1.35 grams per tonne ("g/t") gold and 0.52% copper, respectively.
- Northgate has engaged AMC Mining Consultants ("AMC") to complete technical studies, which will be incorporated into a NI 43-101 compliant Preliminary Assessment.
"We are very pleased with the results of the new resource estimate for Kemess Underground, which has exceeded our initial expectations and increased our confidence in this significant resource" commented Ken Stowe, President and Chief Executive Officer. "In addition to increasing the gold and copper content of the resource, the 2011 drill results have identified a continuous, high-grade sector of the resource, which should allow us to enhance the value of the project if it can be scheduled for mining during the early years of production. In the third quarter of 2011, we look forward to filing a Preliminary Assessment, which will outline the economics for mining a large portion of the identified resources."
Kemess Underground - Synopsis
The 2010 infill diamond drill program was designed and executed to increase confidence in the grade distribution, location and geotechnical characteristics of a target area containing approximately 70 Mt of mineralization that had been identified as potentially mineable using low-cost bulk underground mining methods. The target area is situated in the eastern portion of the Kemess North deposit(1) approximately 300 and 600 metres ("m") below surface. The target zone of 70 Mt was initially estimated to contain approximately 1.4 million ounces of gold and 500 million pounds of copper using a resource model based upon an internal revision of the 2005 NI 43-101 resource estimate for Kemess North and an engineered outline at a $15 Net Smelter Return ("NSR") cut-off for vertical columns of blocks. The target zone was a potentially mineable subset of a larger Indicated Resource of 121.1 Mt containing 2.3 million ounces of gold and 819 million pounds of copper.
Using a $15 block NSR cut-off, the new 2011 Indicated Resource estimate for Kemess Underground is now 136.5 Mt containing 2.6 million ounces of gold, 860.6 million pounds of copper and 9.2 million ounces of silver.
Kemess Underground 2011 Resource
The 2011 resource estimate captures all drilling completed to November 2010 and is based upon a total of 146 drill holes. Initial estimates for underground bulk mining costs, combined with milling and general and administrative (G&A) costs consistent with the size of operation envisioned for the Kemess underground, indicate that a mine could be economically viable with a NSR cut-off in the range of $13-$15 per tonne of ore. Table 1 shows resource estimates for NSR cut-offs of $15 and $13 per tonne and for the "All blocks" area, which has boundaries that are 60 m outside the $13 per tonne NSR cut-off along the western margin and 30 m outside the $13 per tonne NSR cut-off elsewhere.
Table 1: 2011 Kemess Underground Resources (using $1,100/oz gold, $2.80/lb copper and $20/oz silver)
------------------------------------------------------------------------* Includes silver contribution at 55 ounces of silver to one ounce of gold.
Indicated
Cut-Off Tonnes Au Cu Ag Gold* Copper NSR(xx)
(Cdn$/t NSR) (Mt) (g/t) (%) (g/t) (Mozs) (Mlbs) (Cdn$/t)
------------------------------------------------------------------------
$15 136.5 0.558 0.29% 2.105 2.61 860.6 $24.96
$13 162.8 0.513 0.27% 1.992 2.87 964.8 $23.19
All blocks 185.0 0.477 0.25% 1.882 3.04 1032.9 $21.72
------------------------------------------------------------------------
------------------------------------------------------------------------
Inferred
Cut-Off Tonnes Au Cu Ag Gold* Copper NSR(xx)
(Cdn$/t NSR) (Mt) (g/t) (%) (g/t) (Mozs) (Mlbs) (Cdn$/t)
------------------------------------------------------------------------
$15 6.0 0.42 0.22% 1.65 0.09 29.6 $19.07
$13 7.8 0.39 0.21% 1.57 0.10 36.6 $17.96
All blocks 10.2 0.35 0.20% 1.43 0.12 43.7 $16.25
------------------------------------------------------------------------
(xx)NSR or in-situ recovered value assumes metallurgical recoveries of 90% for copper and 68% for gold and an exchange rate of 1.00
At a $15 NSR cut-off, the total Indicated Resource for Kemess Underground is 136.5 Mt containing 2.6 million ounces of gold, 860.6 million pounds of copper and 9.2 million ounces of silver. The 2011 resource is a significant improvement over the May 2010 resource, which showed 121.1 Mt containing 2.3 million ounces of gold and 819 million pounds of copper at a $15 NSR cut-off. This represents an 18% increase in tonnes, a 10% increase in contained gold and a 9% increase in contained copper, resulting from better definition of the +1.0 g/t material within the target area and on improved metal price assumptions.
The 2011 mineral resource estimate will form the basis of a Preliminary Assessment, which Northgate expects to file in the third quarter of 2011 once AMC has completed engineering studies relating to the geotechnical and economic feasibility of developing an underground mine at Kemess.
High-Grade Sector
The 2010 infill drilling reported some of the highest grade intercepts on the Kemess property and it is clear that these intercepts come from a continuous zone measuring 350 m x 180 m x 90 m located adjacent to two faults in the north-east corner of the deposit. The resources within the high-grade sector amount to 10.3 Mt grading 1.35 g/t gold, 0.52% copper and 3.09 g/t silver. There are obvious economic benefits of having 450,000 ounces of gold, 119 million pounds of copper and 1.03 million ounces of silver contained within a small tonnage that could be scheduled for mining early on in the mine-life to provide higher cash flow in the early years and a better payback. Figure 1 shows the location of the high-grade sector relative to the Kemess Underground resource outline.
Figure 1: Plan Map showing Kemess Underground Resource (gray) and the high-grade sector (red). Drill hole traces in blue and 50 m surface elevation contours in grey. Red outline shows $13 mining target area.
Resource Estimate Details
A 20 m x 30 m x 20 m block model was generated by Northgate\'s resource geologist under supervision by the qualified person noted below. Grade for copper and gold was estimated by ordinary kriging interpolation methods from 6 m uncapped composites of diamond drill core samples. Silver grades were estimated using silver analytical values and co-kriged with copper using a cross variogram.
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Quality Control - Analyses and Sample Location
Details of quality assurance/quality control procedures for sample analysis and drill hole survey methodology are reported in detail in the Canadian National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") compliant Technical Report filed on SEDAR (www.sedar.com) on May 6 2005. All 2010 drill holes have had their down hole surveys completed by non-magnetic based instruments such as gyroscope or DeviFlex.
Qualified Persons
The program design, implementation, quality assurance/quality control and interpretation of the results are under the control of Northgate\'s geological staff, which includes a number of individuals who are qualified persons as defined under NI 43-101. Carl Edmunds, PGeo, Northgate\'s Exploration Manager, has reviewed the technical contents of this release.
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Note to Investors:
The terms "Qualified Person", "Mineral Reserve", "Proven Mineral Reserve", "Probable Mineral Reserve", "Mineral Resource", "Measured Mineral Resource", "Indicated Mineral Resource", and "Inferred Mineral Resource" used in this news release are defined in accordance with NI 43-101.
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Northgate Minerals Corporation is a gold and copper producer with mining operations, development projects and exploration properties in Canada and Australia. Our vision is to be the leading intermediate gold producer by identifying, acquiring, developing and operating profitable, long-life mining properties.
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Cautionary Note Regarding Forward-Looking Statements and Information:
This Northgate press release contains "forward-looking information", as such term is defined in applicable Canadian securities legislation and "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995, concerning Northgate\'s future financial or operating performance and other statements that express management\'s expectations or estimates of future developments, circumstances or results. Generally, forward-looking information can be identified by the use of forward-looking terminology such as "expects", "believes", "anticipates", "budget", "scheduled", "estimates", "forecasts", "intends", "plans" and variations of such words and phrases, or by statements that certain actions, events or results "may", "will", "could", "would" or "might" "be taken", "occur" or "be achieved". Forward-looking information is based on a number of assumptions and estimates that, while considered reasonable by management based on the business and markets in which Northgate operates, are inherently subject to significant operational, economic and competitive uncertainties and contingencies. Northgate cautions that forward-looking information involves known and unknown risks, uncertainties and other factors that may cause Northgate\'s actual results, performance or achievements to be materially different from those expressed or implied by such information, including, but not limited to gold and copper price volatility; fluctuations in foreign exchange rates and interest rates; the impact of any hedging activities; discrepancies between actual and estimated production, between actual and estimated reserves and resources or between actual and estimated metallurgical recoveries; costs of production; capital expenditure requirements; the costs and timing of construction and development of new deposits; and the success of exploration and permitting activities. In addition, the factors described or referred to in the section entitled "Risk Factors" in Northgate\'s Annual Information Form for the year ended December 31, 2009 or under the heading "Risks and Uncertainties" in Northgate\'s 2009 Annual Report, both of which are available on the SEDAR website at www.sedar.com, should be reviewed in conjunction with the information found in this press release. Although Northgate has attempted to identify important factors that could cause actual results, performance or achievements to differ materially from those contained in forward-looking information, there can be other factors that cause results, performance or achievements not to be as anticipated, estimated or intended. There can be no assurance that such information will prove to be accurate or that management\'s expectations or estimates of future developments, circumstances or results will materialize. Accordingly, readers should not place undue reliance on forward-looking information. The forward-looking information in this press release is made as of the date of this press release, and Northgate disclaims any intention or obligation to update or revise such information, except as required by applicable law.
Cautionary Note to US Investors Regarding Mineral Reporting Standards:
The Company prepares its disclosure in accordance with the requirements of securities laws in effect in Canada, which differ from the requirements of U.S. securities laws. Terms relating to mineral resources in this press release are defined in accordance with National Instrument 43-101-Standards of Disclosure for Mineral Projects under the guidelines set out in the Canadian Institute of Mining, Metallurgy, and Petroleum Standards on Mineral Resources and Mineral Reserves. The Securities and Exchange Commission (the "SEC") permits mining companies, in their filings with the SEC, to disclose only those mineral deposits that a company can economically and legally extract or produce. The Company uses certain terms, such as, "measured mineral resources" "indicated mineral resources", "inferred mineral resources" and "probable mineral reserves", that the SEC does not recognize (these terms may be used in this press release and are included in the Company\'s public filings which have been filed with securities commissions or similar authorities in Canada).
(1) Kemess North 2005 resource: 719,190,000 tonnes @ 0.30 g/t gold and 0.15% copper.
For further information:
Ms. Keren R. Yun, Director
Investor Relations
Tel: 416-216-2781
Email: ngx@northgateminerals.com
Website: www.northgateminerals.com