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Pretium Resources Inc
Symbol PVG
Shares Issued 94,827,636
Close 2012-11-19 C$ 12.77
Market Cap C$ 1,210,948,912
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Pretium's Brucejack at 16.1Mt of 16.4 g/t Au indicated

2012-11-20 06:20 ET - News Release

Mr. Robert Quartermain reports

PRETIVM RESOURCES INC.: INDICATED GOLD RESOURCES INCREASE BY 66% AT THE VALLEY OF THE KINGS

Pretium Resources Inc. has released the 2012 Valley of the Kings mineral resource estimate for its wholly owned Brucejack project, completed by Snowden Mining Industry Consultants, independent qualified persons. Indicated mineral resources in the Valley of the Kings increased by 66 per cent to 8.5 million ounces of gold at a cut-off grade of five grams of gold equivalent per tonne since the interim Sept. 7, 2012, mineral resource estimate.

Valley of the Kings high-grade gold mineral resources

High-grade gold resources in the Valley of the Kings (five-gram-per-tonne gold-equivalent cut-off) total:

  • 8.5 million ounces of gold in the indicated mineral resource category (16.1 million tonnes grading 16.4 grams of gold per tonne);
  • 2.9 million ounces of gold in the inferred mineral resource category (5.4 million tonnes grading 17.0 grams of gold per tonne).

The mineral resource estimate incorporates data from all drilling to date, including 2012 drilling comprising 99,632 metres in 270 drill holes targeted at the Valley of the Kings. Recent geological interpretation shows Galena Hill to be an extension of the Valley of the Kings. Accordingly, Galena Hill drilling and mineral resources have been incorporated into the Valley of the Kings. Galena Hill comprises 6,284 metres in 14 holes of the total 2012 drilling noted above (plus historical drilling), and contributes 574,000 ounces of gold to the 2012 Valley of the Kings indicated mineral resource. An isometric view of the Valley of the Kings block model is available on-line.

The indicated mineral resource is defined over approximately 600 metres of the total strike length of the Valley of the Kings, which now extends to over 1,000 metres. In addition to the potential of the defined strike length not incorporated into the indicated mineral resource, the Valley of the Kings remains open to the east and west along strike and at depth. A plan view of the Valley of the Kings highlighting the indicated mineral resource is available on-line.

   VALLEY OF THE KINGS MINERAL RESOURCE ESTIMATE -- NOVEMBER, 2012(1)(4)
 (based on a cut-off grade of five grams of gold equivalent per tonne(5))    

                                                            Contained(3)        
                    Tonnes       Gold     Silver          Gold        Silver
Category         (millions)      (g/t)      (g/t)  (million oz)  (million oz)

Indicated             16.1       16.4       14.2           8.5           7.3
Inferred(2)            5.4       17.0       15.7           2.9           2.7

(1) Mineral Resources which are not mineral reserves do not have 
demonstrated economic viability. The estimate of mineral resources may be  
materially affected by environmental, permitting, legal, marketing or other 
relevant issues. The mineral resources in this news release were estimated 
using the Canadian Institute of Mining, Metallurgy and Petroleum, CIM 
Standards on Mineral Resources and Reserves, Definitions and Guidelines 
prepared by the CIM standing committee on reserve definitions and adopted by 
CIM council.                                                
(2) The quantity and grade of reported inferred resources in this estimation
are uncertain in nature, and there has been insufficient exploration to 
define these inferred resources as an indicated or measured mineral resource 
and it is uncertain if further exploration will result in upgrading them to 
an indicated or measured mineral resource category.      
(3) Contained metal figures and totals may differ due to rounding of figures. 
(4) The mineral resource estimate stated in the table is defined using 
10-metre-by-10-metre-by-10-metre blocks in the in Valley of the Kings.
(5) The gold equivalent value is defined as AuEq equals Au plus Ag/53.

Mineral resource modelling and estimation

The November, 2012, mineral resource estimates for Valley of the Kings were completed by Snowden on behalf of Pretium. The mineral resources are classified as indicated and inferred resources in accordance with the CIM Standards on Mineral Resources and Reserves, Definitions and Guidelines prepared by the CIM standing committee on reserve definitions and adopted by CIM council.

Classification is applied based on geological confidence, data quality and grade variability. Areas classified as indicated resources are informed by 20-metre-by-20-metre to 20-metre-by-40 metre drilling. With respect to some of the areas in the high-grade zones at the Valley of the Kings that have drill spacing nearing that of the measured resource previously reported at West zone, Snowden has elected to retain the indicated resource classification until underground sampling has demonstrated a high level of confidence in these estimates. This is because of the high-grade nature of the mineralization. The remainder of the mineral resource is classified as an inferred resource where there is some drilling information and the blocks lie within the mineralized interpretation. Areas where there is no informing data and/or the lower-grade material that is outside of the mineralized interpretation are not classified as a part of the mineral resource.

The mineral resources are reported above a cut-off grade of five grams of gold equivalent per tonne. The gold-equivalent calculation used is: Au plus (Ag/53).

The Brucejack property comprises several gold-silver mineralized areas. These areas include West zone, Valley of the Kings, Galena Hill, Bridge zone, Gossan Hill and Shore zone. The majority of the mineral resource lies within Valley of the Kings and West zone. West zone, Gossan Hill, Shore zone and Bridge zone were not updated for this mineral resource as there has been little additional drilling in these areas. The focus of the 2012 drilling has been on the high-grade Valley of the Kings and Galena Hill areas. Recent geological interpretation shows that the area previously covered by Galena Hill is actually an extension of Valley of the Kings, and this area has now been incorporated into Valley of the Kings.

The Valley of the Kings mineralization is approximately 500 metres south of West zone. The Valley of the Kings mineralized zone trends approximately west-northwest to east-southeast. Its orientation mirrors that of Electrum Ridge, a pronounced topographic feature near the southern margin of the zone, and drilling to date has extended its strike to over 1,000 metres. The zone is up to 170 metres wide and remains open to the west, beyond the Brucejack fault, at depth and to the east. Surface mapping and Pretium's extensive drilling defined a number of lithologic contacts which outline a broad syncline in which fragmental volcanic and clastic sedimentary rocks, along with minor flows of Upper Triassic to Lower Jurassic age appear to plunge moderately to the east.

Pretium used its interpretation of the lithological units at the Valley of the Kings, together with a nominal one-to-three-gram-per-tonne-gold grade cut-off to update the mineralized domains for estimation at the Valley of the Kings.

The input data for the Valley of the Kings estimate comprise 490 drill holes for 174,182 metres, including nine historical surface drill holes (579 metres) and 114 surface drill holes completed since the previous September, 2012, mineral resource (46,944 metres). These figures exclude intervals with no gold values and drill holes outside of the Valley of the King area.

The Valley of the Kings exhibits extremely skewed grade populations where the high grades and the majority of the metal are located in less than 5 per cent of the data, with individual raw gold grades of up to around 41,500 grams per tonne gold. Discussions with Pretium and analysis of the data indicated the mineralization can be split into a pervasive background mineralization and a separate high-grade but discrete mineralization style. As a result of this population distribution, standard estimation techniques have been found to significantly oversmooth the grades.

In order to address the highly skewed nature of the data, Snowden separated the lower-grade "background" population from the higher-grade population within these domains and estimated them independently. All data were composited to the nominal sample length of 1.5 metres prior to analysis and estimation. A threshold of five grams per tonne gold was selected to separate the two populations at the Valley of the Kings. The silver data were treated using the same method with a threshold of 50 grams per tonne silver for Valley of the Kings.

The lower-grade population was estimated using ordinary kriging into 10-metre-by-10-metre-by-10-metre parent blocks. This estimate validates well against the input data.

The higher-grade populations were estimated using multiple indicator kriging to control the skewness of the data. Indicator variograms were modelled up to the 95th percentile of the data with a mathematical model used to define the top end of the grade distribution. The threshold for the 95th percentile of the higher-grade population is 421 grams per tonne gold for the Valley of the Kings. The result of this estimation method is that, while no top cut is used to limit the higher grades, the higher grades are limited in their influence using a mathematical model based on the higher-grade data rather than the individual extreme grades in the dataset. The higher-grade populations were estimated into small-scale discretized blocks and then reblocked into parent blocks twice the size of those used for the lower grades to further limit the influence of the highest grades in the highest-grade areas.

Subsequently, the proportion of the higher-grade mineralization was estimated into each block and used to combine the two estimates (the low-grade portion and the high-grade portion) in the determination of the overall block grade. For example, if a block had a probability of 5 per cent high-grade then the final block grade would combine 95 per cent of the low-grade estimate with 5 per cent of the high-grade estimate. The influence of the high-grade population above the 95th percentile is therefore greatly restricted.

The background (non-mineralized) material was estimated using ordinary kriging with a top cut.

The database used to estimate density is based on pulp specific gravity measurements. As part of the 2012 drilling program, Pretium's qualified person selected a portion of the samples (207 samples) to undergo core density measurements as well as pulp specific gravity measurements in order to determine whether there is any impact on the density as a result of porosity. The results of the comparison indicate that the core density is on average 6 per cent lower than the pulp specific gravity within the siliceous zone and 9 per cent lower on average in all other rock types. As a result the pulp specific gravity measurements, which are used to estimate density in the model, were factored by 6 per cent (siliceous zone) or 9 per cent (other rock types) prior to estimation. Tonnages were estimated on a dry basis with density values estimated into the models using simple kriging where sufficient data were available. Outside of these areas, the average density of 2.54 tonnes per cubic metre was applied. There is little variation in density between the different rock types.

The updated mineral resource estimate for the Valley of the Kings is significantly higher in confidence than the previous September, 2012, estimate as a result of almost twice the amount of drill hole composites within the mineralized corridors. These additional data have resulted in higher confidence in the geological interpretation used in the estimation. The additional drilling confirms the location of the high-grade corridors and has allowed a better estimate of the boundaries of these corridors in areas where there were insufficient data to confirm the location of boundaries previously. The additional confidence has allowed an increase in the amount of material classified as indicated, with much of the higher-grade material previously classified as inferred, now incorporated into the indicated resource. In addition the additional drilling to the east and west of the previously defined mineralized corridors, has allowed an expansion of the inferred resource into these areas.

Bulk sample; feasibility study

Pretium has commenced an underground exploration program designed, amongst other things, to access the Valley of the Kings underground and demonstrate continuity of the high-grade gold mineralization. The first phase, now well under way, is to slash out the existing West zone underground workings to five by five metres then excavate a decline from the West zone to the Valley of the Kings, a distance of approximately 450 metres. The company is currently planning the sampling and mining plans for a 10,000-tonne underground bulk sample, which Pretium expects to excavate from the Valley of the Kings in the second quarter of 2013.

Also under way is a feasibility study for an underground mine with an operating rate of 2,700 tonnes per day using a mining method of long-hole stoping and cemented paste backfill. Stopes will be mined using a combination of longitudinal and transverse mining, depending on zone width and orientation. Cemented paste tailings will be prepared in a paste plant located on surface near the mill and then pumped underground for distribution to the stopes.

With the 66-per-cent increase in the indicated mineral resource at the Valley of the Kings, Pretium plans to incorporate the updated mineral resource in the feasibility study. The feasibility study is currently expected to be completed in the second quarter of 2013, and we will advise in due course on the impact to the schedule.

Independent qualified persons

The table summarizes the high-grade mineral resource estimate totals for the Valley of the Kings zone of the Brucejack project. The mineral resource estimate contained in this news release was prepared by Ivor Jones, FAusIMM(CP), and Lynn Olssen, MAusIMM(CP), of Snowden, both of whom are independent qualified persons, as defined by National Instrument 43-101. Mr. Jones and Ms. Olssen have reviewed and approved the contents of this news release.

We seek Safe Harbor.

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