Increased Resource Estimate to Improve Ngualla Project Economics

Marketwired

WEST PERTH, AUSTRALIA--(Marketwired - Apr 4, 2013) - Peak Resources Limited ("Peak" or "the Company") (ASX: PEK) (OTCQX: PKRLY) is pleased to report a revised Mineral Resource estimate for the Ngualla Rare Earth Project in southern Tanzania. The new estimate incorporates the 13,600m of additional drilling completed in 2012 and is reported according to the 2004 JORC Code and Guidelines.

The infill drilling was completed to increase the amount of weathered mineralisation in the Bastnaesite Zone classified as 'Measured' or 'Indicated' Mineral Resource and provide the definition required for a detailed mine plan and schedule for the project to support the Pre-Feasibility Study now in progress.

The Bastnaesite Zone weathered mineralisation is the high grade, near surface central portion of the greater Ngualla Mineral Resource amenable to a proven, low cost simple sulphuric acid processing route and targeted for production in the initial 25 years of the operation and beyond.

Highlights:

The Mineral Resource for the Bastnaesite Zone weathered mineralisation at a 3.0% lower grade cut-off is:

21.6 million tonnes at 4.54% REO*, for 982,000 tonnes of contained REO#

Ngualla has the highest grade of all the rare earth development projects.

The new Mineral Resource estimate is a significant increase over the 8.2 million tonnes at 4.35% REO in the December 2012 Scoping Study mine plan, which supports an initial 25 year mining period and 10,000tpa REO production level.

The revised Mineral Resource illustrates the potential to support increased production levels and an extended mine life based on a simple sulphuric acid leach operation.

An increased production rate, higher grades and the enhanced beneficiation ability indicated by recent test work as announced on 6th March 2013 will significantly improve the already very strong NPV and IRR of the December Scoping Study.

Of the total Bastnaesite Zone Mineral Resource, 99.6% is now classified in the 'Measured or Indicated' category, with the majority (86%) being 'Measured'.

The Measured and Indicated portions of the Bastnaesite Zone will form the basis for a maiden Reserve estimate for the project to be completed as part of the Pre-Feasibility Study which is now in progress.

The extremely low levels of uranium and thorium in the Bastnaesite Zone weathered Mineral Resource of 14ppm and 42ppm respectively are a distinct advantage over other rare earth projects.

*= total rare earth oxides plus Y2O3 #=see Table 1 for classification of Mineral Resource

At a 1% lower grade cut-off, the total Mineral Resource estimate for Ngualla has increased by 15% in terms of tonnes and contained REO compared to the 2012 maiden Mineral Resource estimate. At a 1% lower grade cut off, the new Mineral Resource estimate is:

195 million tonnes at 2.26% REO, for 4.4 million tonnes of contained REO#.

#= see Table 2 for classification of Mineral Resource

Ngualla remains one of the largest and highest grade rare earth deposits in the world.

Metallurgical test work has shown that mineralisation outside of the Bastnaesite Zone may be processed using other conventional beneficiation and leach processing routes. The long mine life supported by the Bastnaesite Zone provides the Company with the opportunity and time to optimise these processes, which could be brought in at a later stage in the life of the operation.

Richard Beazley commented further, "The new estimate illustrates the quality of the Ngualla Resource, the economic upside and the options available to Peak to expand production once the initial low cost, low risk operation has been established."

Technical Report
Peak has moved the Ngualla Rare Earth Project forward rapidly from discovery in August 2010 to the release of the maiden Mineral Resource on 29th February 2012. The new revised Mineral Resource incorporates an additional 13,600m of reverse circulation (RC) and diamond drilling completed during the 2012 field season subsequent to the release of the maiden Mineral Resource.

Geochemical, mineralogical and metallurgical work completed after the release of the maiden Mineral Resource has identified an important and high grade portion of the Ngualla deposit that is amenable to a sulphuric acid leach processing route. This metallurgical process is efficient in extracting rare earths from weathered mineralisation within the Bastnaesite Zone (Figure 1). The relatively simple process uses conventional technology of 'tanks, pumps and filters' to efficiently extract rare earths at low cost and contributes to a low risk operation that Peak believes can be rapidly brought into production and presenting a distinct commercial advantage over other rare earth projects.

The revised 2013 Mineral Resource therefore includes an important new subset -- the Bastnaesite Zone weathered mineralisation. The total Ngualla Mineral Resource is also presented to enable comparison with the 2012 maiden Mineral Resource, at the same lower cut-off grades of 1.0% and 3.0%.

Additional drilling completed in 2012 focussed on infilling the high grade central Bastnaesite Zone portion of the Ngualla deposit to provide the definition required for a high confidence, well drilled Mineral Resource, the majority of which would move into the 'Measured or Indicated' categories of the JORC system.

The new Mineral Resource is based on four phases of drilling comprising over 40,400m of drilling in 781 drill holes. The last phase of drilling was completed on 30th November 2012.

The Mineral Resource estimate reported according to the JORC Code and Guidelines was completed by independent resource consultants H&S Consultants Pty Ltd for the Bastnaesite Zone and total Ngualla deposit (Figure 1).

Block grades in a 20m x 20m x 5m block model were assigned using Ordinary Kriging geostatistical techniques from two metre sample composites with searches aligned parallel to the strike and dip of the mineralisation. Density measurements collected from 16 diamond core holes located in or surrounding the main mineralised zones were applied to the 2m composite samples on the basis of rock type. Further modelling parameters are detailed in the 'Notes on Resource Estimation' at the rear of this report.

The Bastnaesite Zone weathered Mineral Resource

The Mineral Resource estimate for the Bastnaesite Zone weathered mineralisation above a 3% REO grade cut off is:

21.6 million tonnes at 4.54% REO, for a total of 982,000 tonnes of REO

(See Table 1 for classification details)

This is a significant increase over the 8.2 million tonnes at 4.35% REO in the December 2012 Scoping Study mine plan that supports an initial 25 year mining period and 10,000tpa REO production level.

The Bastnaesite Zone Mineral Resource has very low uranium and thorium levels of 14ppm and 42ppm respectively.

The new Mineral Resource clearly illustrates the potential to increase production levels and extend mine life based on this high grade, near surface mineralisation and a simple sulphuric acid leach processing operation. The impact of this and the recent advances in beneficiation on the economics of the operation as defined by the December 2012 Scoping Study will be substantial.

The Scoping Study confirmed Ngualla as a leading rare earth project with an estimated NPV of US$1.57 billion and pre-tax IRR of 53%. Other summary financials included:

  • Low capital cost requirement of US$400 million (excluding contingency) with a payback period within the first 3 years of production.
  • Low operating cash costs of US$10.09 per kg Free on Board "FOB" for the first 5 years of production with an average cost of $US11.05 per kg over 25 years.
  • Annual average revenues of US$361 million at 10,000 tonne equivalent rare earth oxide production.

The increased amount of high grade mineralisation and option to increase production rates, coupled with the enhanced beneficiation ability indicated by recent test work will lower cash costs and improve the already strong NPV and IRR of the December Scoping Study.

Of the total Bastnaesite Zone Mineral Resource, 99.6% is classified in the 'Measured or Indicated' categories, with the majority (86%) being Measured (Table 1). The Measured and Indicated Bastnaesite Zone portion of the total Mineral Resource will form the basis for a maiden Reserve estimate for the project to be completed as part of the Pre-Feasibility Study now in progress.

The Pre-Feasibility Study will include a revised economic assessment for the project and quantify these improved economic parameters.

 
 
Table 1: Classification of Mineral Resources for the Bastnaesite Zone weathered mineralisation at a 3.0% cut off grade.
Lower cut - off JORC Resource Tonnage REO Contained
grade Category (Mt) (%)* REO tonnes
  Measured 19 4.53 840,000
         
  Indicated 2.9 4.62 140,000
         
3.0% REO Inferred 0.11 4.10 4,000
         
  TOTal 21.6 4.54 982,000
*REO (%) includes all the lanthanide elements plus yttrium oxides. See Table 3 for breakdown of individual REO's. Figures above may not sum precisely due to rounding. The number of significant figures does not imply an added level of precision.

The distribution of individual rare earths plus yttrium oxides that make up the total for the 3.0% REO grade cut is shown in Table 3. This distribution is similar to other carbonatite hosted rare earth projects such as Lynas's Mt Weld Deposit in Western Australia, and Molycorp's Mountain Pass operation in California.

The Bastnaesite Zone weathered mineralisation is located in the geological core of the Ngualla Carbonatite and consists of highly weathered and ferruginous carbonatite, gravel and ferricrete. Mineralogical test work has identified that rare earths occur as the fluoro-carbonate mineral bastnaesite within an iron oxide rich host rock with barite and silica.

Extensive acid leach variability test work on a total number of 211 samples has shown that an average of 82.3% extraction of rare earths can be expected using a simple sulphuric acid leach process from this style of mineralisation (Figure 3). The high leach extraction efficiency has been confirmed by additional test work completed on bulk composite drill samples.

The readily leachable weathered Bastnaesite Zone mineralisation is identified by calcium contents of less than 10% and low phosphorous contents.

The high grade weathered mineralisation within the Bastnaesite Zone occurs from surface and extends to depths of over
180m. Grades are evenly distributed and the morphology of the mineralisation enables low cost open pit mining with very low strip ratios.

Comparison of the 2013 revised and 2012 maiden Mineral Resource estimates

The total Mineral Resource for the Ngualla Project above a 1% REO cut-off is:

195 million tonnes at 2.26% REO, for a total of 4.4 million tonnes of REO

(See Table 2 for classification details and comparison to 2012 maiden Mineral Resource)

The distribution of individual rare earths plus yttrium oxides that make up the total for the 1% cut is shown in Table 3.

This Mineral Resource estimate represents an increase of 15% in both tonnes and contained REO at a slightly higher overall grade (Table 2).

This is:

42 million tonnes at 4.19% REO, for a total of 1.8 million tonnes of REO.

(See Table 2 for classification details and comparison to 2012 maiden Mineral Resource)

The average individual REO distribution for each of the two Mineral Resource zones is shown in Table 3.

 
 
Table 2: Comparison of 2012 maiden and 2013 revised Mineral Resources and classification of Mineral Resources for the Ngualla Rare Earth Project, 1.0% and 3.0% REO cut-off grades.
 
 March 2013 Revised Resource

 February 2012 Maiden Resource

 Lower cut - off grade

JORC Resource
Category

Tonnage
(Mt)

 REO (%)*

 Contained
REO tonnes

Tonnage
(Mt)

 REO (%)*

 Contained
REO tonnes




1.0% REO

 Measured

 81

 2.66

 2,100,000

 29

 2.61

 750,000

 Indicated

 94

 2.02

 1,900,000

 69

 2.43

 1,700,000

 Inferred

 20

 1.83

 380,000

 72

 1.92

 1,400,000

TOTal

195

2.26

4,400,000

170

2.24

3,800,000




3.0% REO

 Measured

 27

 4.33

 1,200,000

 11

 3.99

 430,000

 Indicated

 13

 3.99

 520,000

 21

 4.09

 850,000

 Inferred

 1.7

 3.56

 60,000

 8.7

 4.11

 360,000

TOTal

42

4.19

1,800,000

40

4.07

1,600,000
*REO (%) includes all the lanthanide elements plus yttrium oxides. See Table 3 for breakdown of individual REO's. Figures above may not sum precisely due to rounding. The number of significant figures does not imply an added level of precision.

Ngualla remains one of the largest and highest grade rare earth deposits in the world. The +3% weathered Bastnaesite Zone mineralisation comprises just 22% of this global +1% Mineral Resource. Metallurgical test work has shown that rare earth mineralisation in this remaining portion of the deposit may be amenable to processing using other conventional beneficiation and leach processing routes.

Mixed bastnaesite-monazite weathered mineralisation surrounds the central Bastnaesite Zone at Ngualla. Initial test work on samples of this second style of mineralisation achieved 94% extraction of rare earths using a standard sulphuric acid bake process.

Fresh rock carbonatite hosted rare earth mineralisation grading 1.5% to 2.5% REO underlies the high grade weathered Bastnaesite Zone mineralisation over a 870m x 560m area and remains open at depth beneath the current limit of drilling at approximately 180m from surface. This very large tonnage rare earth deposit compares favourably in size and grade to some other deposits being considered for development (Figures 4 and 5). Simple wet table characterisation of this third style of mineralisation at Ngualla has produced positive beneficiation results in preliminary sighter tests. Initial single stage flotation work has produced a substantial upgrade to feed mineralisation and subsequent leaching has successfully extracted rare earths from the concentrate produced.

The long mine life supported by the Bastnaesite Zone provides the Company with the opportunity and time to optimise these processes that could be brought in at a later stage in the life of the operation to develop the large tonnages of these styles of rare earth mineralisation available at Ngualla.

 
 
Table 3: Relative components of individual rare earth element oxides (including yttrium) as a percentage of total REO for the "2013 weathered Bastnaesite Zone +3% REO" and "Total Ngualla +1% REO" Mineral Resources.
   
OxIDE
 
Bastnaesite Zone Mineral
Resource at 3.0% REO cut
 
Ngualla total Mineral
Resource at 1.0% REO cut

light
Rare Earths
  Lanthanum   La2O3   27.6   27.1
Cerium   CeO2   48.2   48.2
Praseodymium   Pr6O11   4.73   4.81
" > " Neodymium   Nd2O3   16.6   16.3
Samarium   Sm2O3   1.60   1.67

Heavy
Rare Earths
  " > " Europium   Eu2O3   0.30   0.35
Gadolinium   Gd2O3   0.61   0.76
" Terbium   Tb4O7   0.05   0.07
" Dysprosium   Dy2O3   0.08   0.16
Holmium   Ho2O3   0.01   0.02
Erbium   Er2O3   0.03   0.06
Thulium   Tm2O3   0.00   0.00
Ytterbium   Yb2O3   0.01   0.02
Lutetium   Lu2O3   0.00   0.00
Other   " Yttrium   Y2O3   0.20   0.48
        Total %   100   100
The blue markers (•) denote the five "critical rare earths", which are predicted to be in undersupply in the years ahead and predicted to command significantly higher value than other rare earths. (US DoE, 'Critical Materials Strategy' report, December 2011).
 
The critical rare earths contribute the majority of the value from Ngualla at 56% of the in ground value. Of these, neodymium is the main single rare earth value driver, contributing 34%, (relative rare earth oxide prices: Metal Pages, 11th September 2012).

About the Ngualla Rare Earth Project:
The Ngualla Rare Earth Project in Tanzania is a recent discovery and is the highest grade of the large undeveloped rare earth deposits.

Fundamental geological aspects offer distinct advantages for development over other rare earth projects. These include the large size of the deposit, outcropping, high grade mineralisation amenable to open cut mining with low strip ratios, favourable mineralogy amenable to a relatively simple, low cost processing route and the lowest uranium and thorium levels of any major rare earth deposit in the world.

The favourable characteristics of the central Bastnaesite Zone targeted for first production distinguish Ngualla from all other rare earth development projects and are reflected in the results of the Scoping Study and preliminary economic assessment released to the ASX on 3rd December 2012. These indicate very low capital and operating costs compared to other rare earth projects.

The Pre-Feasibility Study and revised economic assessment now in progress and scheduled for completion in Q3 2013 are expected to continue to significantly enhance these robust project economics through:

  • Further beneficiation and hydrometallurgical process optimisation reducing Opex and Capex further
  • The revised Mineral Resource model detailed in this report

A range of high purity separated rare earth oxide products from the SX Pilot Plant will be available for assessment by potential off take customers in Q2 2013.

Peak has appointed financial advisors to work with the Company in identifying and securing strategic partners to assist in funding the Ngualla Rare Earth Project through to production. Discussions with a number of interested parties are ongoing.

The Company continues to fast track the development of Ngualla with the aim of becoming a low cost, long term producer of high purity rare earth oxide products by Q1 2016.

Richard Beazley Managing Director

The information in this report that relates to Mineral Resources is based on information compiled by Robert Spiers, who is a member of The Australasian Institute of Geoscientists. Robert Spiers is an employee of geological consultants H&S Consultants Pty Ltd. Robert Spiers has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Robert Spiers consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

The information in this report that relates to Metallurgical Test Work Results based on information compiled and / or reviewed by Gavin Beer who is a Member of The Australasian Institute of Mining and Metallurgy. Gavin Beer is a Consulting Metallurgist with sufficient experience relevant to the activity which he is undertaking to be recognized as competent to compile and report such information. Gavin Beer consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

The information in this report that relates to Exploration Results is based on information compiled and/or reviewed by Dave Hammond who is a Member of The Australasian Institute of Mining and Metallurgy. Dave Hammond is the Technical Director of the Company. He has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves". Dave Hammond consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.

Notes on Resource Estimation

Competency Statement

The Resource estimates were prepared by Robert Spiers (MAIG) who is a Director and full time employee of H&S Consultants Pty Ltd. All resource work was peer reviewed by Dr Phillip Hellman FAIG, who is a full time employee of H&S Consultants Pty Ltd. Both Robert and Phil have sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activities which are being undertaken to qualify as Competent Persons as defined in the 2004 Edition of the "Australian Code for Reporting of Mineral Resources and Ore Reserves."

Robert Spiers consents to the inclusion of the aforementioned estimates in the form and context in which they appear.

Definitions

TREO is defined as the total oxides of the 14 rare earth elements; Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu) but excluding Promethium (Pm); plus the transition metal Yttrium (Y).

Quality assurance and quality control

The surveying, sampling and assaying carried out by Peak Resources and its contractors has had rigorous QAQC applied to them to ensure accuracy of the drilling data.

Geology and Mineralisation

The Ngualla carbonatite complex in southwest Tanzania has a circular outline with a diameter of approximately 4 X 3.5 km and is pipe-like in form. It was intruded into Precambrian gneisses, quartzites and rhyo-dacitic volcanic. The age of the intrusions is uncertain but a K-Ar age of 1,040 (±40) Ma for igneous biotite was determined by Cahen and Snelling (1966).

The predominant components of the complex are an annular calcite carbonatite and a central plug of "ferrocarbonatite". Whole-rock geochemical data indicate that the latter is actually magnesiocarbonatite but the term "ferrocarbonatite" is used locally to distinguish the central plug from barren magnesiocarbonatite dykes with a similar bulk composition. Magnesiocarbonatite dykes cut the calcite carbonatite but these are cut by "ferrocarbonatite" dykes emanating from the central plug. The contact between the central plug and the annulus is a 200 metre wide zone of "ferrocarbonatite" dykes and calcite carbonatite xenoliths known locally as the transitional carbonatite.

Rare earth elements are concentrated in the "ferrocarbonatite" as synchesite and bastnaesite where it occurs in miarolitic domains interstitial to ferroan dolomite. Weathering of the "ferrocarbonatite" in structurally-controlled zones has upgraded the REE concentration by dissolution of MgCO3 and CaCO3, leaving a porous goethite- and barite-rich rock without significant modification of the REE mineralogy.

Drilling and Sampling

A detailed resource development drilling data set for the entire Ngualla Project area was made available to H&SC. The dataset contained a total of 781 collar records, 21,276 assay records, 7,104 geology records and 1,470 survey records which were assessed during the geological modeling process. All drill hole types including RC (reverse circulation), DD (diamond core) and AC (aircore) data were employed during the estimation process.

Drill hole spacing over the main mineralized zone was essentially on a 40mx50m (hole and line spacing respectively) grid pattern. At the periphery of the main mineralized zone and including the south-western alluvial zone the drill spacing was primarily on an 80mx100m (hole and line spacing respectively) grid pattern with infill on every second line down to 40mx100m (hole and line spacing respectively).

All sampling was conducted using standard 1 metre riffle splits from the RC drill cyclone. The 1m splits were then combined in the field with the subsequent 1m sample to form a 2m composite for final assay submission.

Cut-off grades

Reported cut-off grades have been based on the assumptions made by Peak Resources that are believed to be realistic in terms of current considerations of prices, processing and mining costs and the marketability of the TREO+Y2O3 Resource.

It is generally assumed that the prospects represent the resources that are being targeted for open cut mining and production by the Company.

Assaying

The entire list of elements which were routinely assayed for included:

Al   As   Au   Ba   Ca   Ce   Cr   Cu   Dy   Er   Eu   Fe   Gd   Ho   K   La   Li
Ho   K   La   Li   Lu   Mg   Mn   Mo   Na   Nb   Nd   Ni   P   Pb   Pr   S   Sb
Sc   Si   Sm   Ta   Tb   Th   Ti   Tm   U   Y   Yb   Zn    Zr                

The analysis was undertaken by SGS Laboratories, Perth, Western Australia by 4 acid digest and ICP, or XRF fusion or XRF pressed powder.

Geological Interpretation and Modeling

Geological interpretation of drill-hole cross sections and plan projections was completed by Peak Resources representatives in conjunction with H&SC and then wireframed utilising Micromine software to create a three dimensional geological model of the mineralisation. The wireframes were used to code the data set upon which the resources were estimated in a block model with dimensions of 20 x 20 x 5 metres (x, y, z).

Density analysis was completed using 713 individual readings. The data was collected from 16 separate diamond holes all located within and / or surrounding the main mineralized zones in the central southern portion of the project area. After analysis of the available density data a range of between 1.81 to 3.00 tonnes/m3 was observed to exist within the dataset. The density determinations compiled from the density analysis were kriged as an element of the modeling process to produce a unique density value for each block in-line with modeling criteria.

Resource Estimation

The resource model was undertaken using Ordinary Kriging ("OK") from two metre composites within the mineralised zones using three estimation passes with the searches aligned parallel to the strike and dip of the mineralisation. H&S's proprietary software, GS3 was used for estimation. This approach was validated against the original data on section and in plan to ensure model integrity and global representativeness of TREO+ Y2O3ppm above a range of nominated cutoff grades.

Blocks in the resource model have been allocated a confidence category based on the number and location of samples used to estimate the grade of each block in conjunction with sample recovery, geological and structural variability and all QAQC aspects. The search parameters used to determine the classification of a block within the resource in this study are:

  • Minimum number of samples found in the search neighborhood
    For Measured and Indicated categories, this parameter is set to sixteen. For Inferred category, a minimum of eight samples is required. This parameter ensures that the block estimate is generated from a reasonable number of sample data.

  • Minimum number of spatial quadrants informed.
    The space around the centre of a block being estimated is divided into octants by the axial planes of the data search ellipsoid. This parameter ensures that the samples informing an estimate are relatively evenly spread around the block and do not all come from one drill hole. For Measured and Indicated categories, all four quadrants must contain at least 16 samples combined. For Inferred blocks a minimum of 2 quadrants must contain at least 8 samples combined.

  • The distance to informing data.
    A three pass approach was adopted for primary domains one (transported material) and two (strongly weathered bedrock). For the Measured category, the search radii are set to 80mE by 100mN by 25mRL respectively for the first pass. For Indicated and Inferred, the search radii are set to 160mE by 200mN by 50mRL respectively and the data criteria are reduced by half to minimum data of 8 in at least two octants by use of an expansion equal to 1.0.

For primary domain three (transitional and fresh bed rock) a three pass approach was adopted. For the Measured category, the search radii are set to 20mE by 80mN by 20mRL respectively for the first pass. For Indicated and Inferred, the search radii are set to 35mE by 140mN by 35mRL respectively and the data criteria are reduced by half to minimum data of 8 in at least two octants by use of an expansion equal to 0.75.

Contact:


Peak Resources Limited
Richard Beazley
Managing Director
Phone: +61-8-9200-5360
Email: richard@peakresources.com.au

MZ Group - North America
Derek Gradwell
SVP
Natural Resources
Phone: 949-259-4995
Email: dgradwell@mzgroup.us
Web: www.mzgroup.us
View Comments (0)