1st Quarter Results

RNS Number : 9295P
Berkeley Resources Limited
31 October 2012
 



ASX RELEASE

31 October 2012

SEPTEMBER 2012 QUARTERLY REPORT

Berkeley Resources Limited ('Berkeley' or the 'the Company') is pleased to present its quarterly report for the period ended 30 September 2012. Highlights during, and subsequent to, the quarter include:

 

·   The initial assessment of the integrated development of Retortillo and Alameda has continued to be the Company's focus during the September quarter.

     A comprehensive review of the extensive work programs already completed at Retortillo and Alameda has been undertaken and the information generated from these previous studies, as well as new, more recently completed drilling and metallurgical testwork data has formed the basis for a Scoping Study ('the Study'), which is scheduled for completion in the December quarter.

     The key considerations for the Study are preferred mining and processing route, scale, throughput rate, mine life, as well as development of the associated infrastructure taking due cognisance of community and environmental impacts.

 

·   The final results of a metallurgical test work undertaken at Mintek's mineral processing facility in Johannesburg, on a 5.5 tonne representative bulk sample from Retortillo, were received. The results indicate metallurgical recoveries in the range of 85% to 90%, with acid consumption of less than 20 kilograms per tonne.

 

·   Assay results from an additional 16 reverse circulation ('RC') and three diamond holes drilled at Gambuta confirmed the continuity of thick zones of high grade mineralisation at shallow depths, with best intercepts including 11 metres at 1,428 ppm U3O8 from 12 metres, 22 metres at 1,319 ppm U3O8 from 32 metres and 8 metres at 835 ppm U3O8 from 21 metres. The drilling results clearly demonstrate the exploration potential of Gambuta and surrounding targets.

     The drilling results were incorporated into an updated Gambuta Mineral Resource Estimate ('MRE'), resulting in a 20% increase in contained uranium to 11.1 million pounds.     

 

·   The permitting process for Retortillo progressed with the 30-day Public Information Period being completed in mid-September. Core documents submitted as part of the public information process included the Exploitation Plan, Restoration and Closure Plan, and the Environmental and Social Impact Assessment ('ESIA'). The public comments were received in late September and the Company is currently preparing responses to these comments.

 

·   Berkeley Minera España, S.A., a subsidiary of the Company, obtained ISO 14001 (Environmental Management) and UNE 22480 (Sustainable Mining Management) certification in September.

 

 

 

Enquiries:                         Robert Behets                         Martin Eales

                                            Berkeley Resources               RBC Capital Markets

+61 8 9322 6322                     +44 20 7029 7881

 

OPERATIONS

Berkeley Resources Limited ('Berkeley' or 'the Company') is a uranium exploration and development company with a quality resource base in Spain. Berkeley is currently focused on advancing its wholly owned flagship Salamanca Project, which comprises the Retortillo, Alameda and Gambuta deposits plus a number of other Satellite deposits, through the development phase.

 

SALAMANCA PROJECT

Drilling and Mineral Resource Estimation

Retortillo and Alameda

Diamond drilling programs at Retortillo and Alameda commenced late in the quarter. The drilling is planned to facilitate further resource definition and to provide drill core for the next phase of metallurgical test work.

 

Gambuta

A limited program of resource infill drilling in the north-western portion of the Gambuta Deposit was completed during the June quarter of 2012. Following receipt of the assay results, the mineral resource has been re-estimated, resulting in a 20% increase in contained uranium to 11.1 million pounds at an average grade of 394 ppm U3O8 at a lower cut-off grade of 200 ppm U3O8. This increase reflects the results of the drilling which intersected thicker zones of high grade mineralisation and extended the limits of this sparsely drilled deposit.

 

Drilling by Berkeley in 2008 outlined mineralisation up to 300 metres in width over a strike length of approximately 1,500 metres. The flat lying mineralised horizons range from 2 metres to 20 metres in thickness, are located predominantly within the partially weathered zone, and at depths from surface to 100 metres. A total of 43 widely spaced diamond and RC holes resulted in an initial Inferred MRE, reported in August 2008, of 11.3 million tonnes averaging 371 ppm U3O8 for a contained 9.2 million pounds of U3O8 at a lower cut-off grade of 200 ppm U3O8. The Company's subsequent focus on the resources located within the State Reserves (e.g. Alameda) and at Retortillo however, precluded more detailed drilling at Gambuta until this year.

An additional 16 RC drill holes for 1,229 metres and three diamond drill holes for 269 metres were completed as part of an infill program focussed on the north-western portion of the deposit. The diamond drill holes also provided material for metallurgical testwork on the Gambuta mineralisation.

 

Assay results returned from this drilling confirmed the continuity of thick zones of high grade mineralisation at shallow depths, slightly extended the mineralisation on the northern and southern boundaries, and included thicker intersections than recorded in the previous drilling. Select intersections (quoted as down-hole intercepts which approximate true widths) are included in Table 1.

Table 1: Gambuta Drilling - Significant Intersections (200 ppm U3O8 cut-off)

Hole No.

Down Hole Intercept

From Depth

(Down Hole)

GMR-045

8m @ 649 ppm U3O8

50m


3m @ 3,083 ppm U3O8

85m

GMR-048

7m @ 666 ppm U3O8

34m

GMR-049

7m @ 672 ppm U3O8

36m

GMR-056

11m @ 1,428 ppm U3O8

12m


22m @ 1,319 ppm U3O8

32m

GMR-058

5m @ 905 ppm U3O8

23m

GMR-059

8m @ 835 ppm U3O8

21m

GMR-060

4m @ 1,126 ppm U3O8

43m

The drilling results clearly demonstrate the exploration potential of Gambuta and surrounding targets.

All intersections returned from the drilling, along with the details of the collar positions, dips, azimuths and depths, are summarised in Appendix A.

The updated MRE has been based on a new wireframe interpretation and block model. Ordinary kriging was applied to estimate grade into the block model. The updated MRE has been estimated at 12.7 million tonnes averaging 394 ppm U3O8 for a contained 11.1 million pounds of U3O8 at a lower cut-off grade of 200 ppm U3O8 (Table 2). The MRE has been classified into the Inferred category due to the broad drill spacing for this style of vein-hosted uranium mineralisation. Further details of the resource estimation methodology are provided in Appendix B.

The updated MRE represents a 12% increase in tonnes, a 6% increase in average grade, and a 20% increase in contained uranium compared to the previously reported MRE (August 2008). This increase reflects the better drill results received and highlights the potential to further expand the resource with additional drilling.

Table 2: Gambuta Deposit - Mineral Resource Estimate

Gambuta Deposit

Inferred Mineral Resource Estimate - October 2012

Lower Cut-off

(U3O8 ppm)

Tonnage

(million tonnes)

Grade

(U3O8 ppm)

Contained U3O8

(million pounds)

500

  2.9

699

  4.5

400

  4.6

603

  6.1

300

  7.2

509

  8.1

200

12.7

394

11.1

100

24.5

274

14.8

0

35.1

210

16.3

 

The grade tonnage curves highlight the significant impact that the cut-off grade used has on the resource estimate. At a 100 ppm U3O8 lower cut-off grade the resource estimate totals 24.5 million tonnes averaging 274 ppm U3O8 for for a contained 14.8 million pounds U3O8. This represents a 33% increase in contained uranium when compared with the MRE at the 200 ppm lower cut-off grade (Table 2). This additional potential is considered very significant given that studies at Retortillo based on uranium recovery by heap leaching point to enhanced economies at cut-off grades of approximately 100 ppm U3O8.

 

The Company will continue to advance Gambuta, with a view to further expanding the resource base and fully integrating it into the ongoing appraisal of the Salamanca Project.

 

Details of all Berkeley drilling completed during the quarter and year to date are summarised in Table 3.

 

 

Table 3: 2012 Drilling Summary

RC Q1 2012

RC Q2 2012

RC Q3 2012

RC TOTAL 2012

Holes

Metres

Holes

Metres

Holes

Metres

Holes

Metres

Retortillo

Retortillo Satellites

Gambuta

Total

133

7,790

16

1,229

0

0

149

9,019


DD Q1 2012

DD Q2 2012

DD Q3 2012

DD Total 2012

Holes

Metres

Holes

Metres

Holes

Metres

Holes

Metres

Retortillo

Gambuta

Alameda

Total

12

735

9

777

2

114

23

1,626

 

 

Metallurgical Testwork

The final report for the full-scale metallurgical testwork program undertaken on a 5.5 tonne bulk sample, representative of the Retortillo deposit, at Mintek's mineral processing facility in Johannesburg, was received during the quarter. 

 

Uranium recovery, leach times and acid consumption have been calculated for the nine 6m columns. The recovery was reasonably consistent across all columns, with an average of 90% after 70 days. Accordingly, a total uranium recovery of 90% appears feasible at the tested P80 40mm crush size in a properly scaled-up commercial leach cycle of 140 days for a heap stacked to a height of 6m. Given expected variability in head grade, ore type and other operating conditions, recoveries in the range of 85% to 90% are assumed. This outcome is consistent with the previously assumed recoveries for Retortillo. A bacterial leach was also demonstrated to be is sufficient to leach the Retortillo ore meaning an external chemical oxidant is not required in the process.

 

The testwork results indicated acid consumption will range from 15 kg/t to 20 kg/t, inclusive of the addition of approximately 8 kg/t to 10 kg/t of acid in the agglomeration process, for the bacterial leach scenario. There is potential to reduce the total acid consumption through further optimisation of the acid addition in agglomeration.    

 

Analytical data of the pregnant liquor solution ('PLS') obtained and solvent extraction ('SX') testwork also indicates that there are no impurities at levels that could adversely impact the quality of the yellow cake to be produced. The leach solution has low concentrations of all common penalty elements.

 

Project Evaluation

The initial assessment of the integrated development of Retortillo and Alameda has continued to be the Company's focus during the September quarter.

 

A comprehensive review of the extensive work programs already completed, including a Preliminary Feasibility Study ('PFS') completed in early 2012 for a stand-alone project exploiting Retortillo and a separate Feasibility Study completed in 2011 which incorporated Alameda, has been undertaken.

 

The information generated from these previous studies, as well as new, more recently completed drilling and metallurgical testwork data has formed the basis for a Scoping Study ('the Study') on the integrated development Retortillo and Alameda.

 

The key considerations for the Study are preferred mining and processing route, scale, throughput rate, mine life, as well as development of the associated infrastructure taking due cognisance of community and environmental impacts.

 

The basic conceptual approach to the development of Retortillo and Alameda contemplated in the Study includes:

·     Open pit mining (transfer mining to facilitate continuous rehabilitation)

·     Heap leaching using on-off leach pads

·     Centralised solvent extraction ('SX') and ammonium diuranate ('ADU') precipitation plant, located at Retortillo

·     Remote ion exchange ('IX') operation at Alameda, with loaded resin trucked to the centralised plant for final extraction and purification

 

The Study is due for completion in the December quarter.

 

Permitting

The 30-day Public Information Period for Retortillo was completed in mid-September. Core documents submitted as part of the public information process included the Exploitation Plan, Restoration and Closure Plan, Environmental and Social Impact Assessment ('ESIA'), Initial Authorisation of the Process Plant as a Radioactive Facility, and Exceptional Authorisation for Land Use (application for reclassification from rural to mining use).

 

The public comments were received in late September and the Company is currently preparing responses to these comments. The Company's responses will be subject to clearance and direction from the authorities before they are incorporated into the Project.

 

Environment and Sustainable Mining Management

Sustainable Mining Management, including environmental responsibility, radiological protection and community awareness, engagement and support are paramount considerations for Berkeley.

 

To this end, Berkeley Minera España, S.A. ('BME'), a subsidiary of the Company, obtained ISO 14001 (Environmental Management) and UNE 22480 (Sustainable Mining Management) certification In September.

 

 

CORPORATE

At 30 September 2012 the Company had cash reserves of A$34.5 million.

 

 

The information in this announcement that relates to Exploration Results and Mineral Resources is based on information compiled by Mr Craig Gwatkin, who is a Member of The Australian Institute of Mining and Metallurgy and is a full-time employee of Berkeley Resources Limited. Mr Gwatkin 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 ('The JORC Code'). Mr. Gwatkin consents to the inclusion in the announcement of the matters based on his information in the form and context in which it appears.

Appendix A: Summary of RC and Diamond Drill Intersections - Gambuta Deposit

Drill Intersections  > 200ppm U3O8

Hole ID

Easting

Northing

Elev.

Depth

Azim

Dip

From

To

Thick

U3O8


(m)

(m)

(m)

(m)

(º)

(º)

(m)

(m)

(m)

(ppm)

 

 

Drill Intersections  > 200ppm U3O8

Hole ID

Easting

Northing

Elev.

Depth

Azim

Dip

From

To

Thick

U3O8


(m)

(m)

(m)

(m)

(º)

(º)

(m)

(m)

(m)

(ppm)

Notes:

Coordinates are in UTM Grid (ED1950 Zone 30N) and have been measured by a DGPS (+/- one metre accuracy)

RC drill samples are collected over one metre intervals using representative sampling techniques

The mineralisation is hosted by metasediment, typically in the first 90 metres below surface and is interpreted to be flat lying. Thus reported intervals approximate true widths

Sample preparation by ALS Chemex laboratory in Sevilla, Spain, with sample analysis of U by ALS Chemex in Vancouver, Canada by XRF pressed pellet

Quality control standard, blanks and duplicates are routinely included with all drill samples prior to submission to the laboratory, where further laboratory control standards are added

GMD prefix denotes diamond drill holes

   * results based on down-hole equivalent grades

 

Appendix B: Criteria used in the Mineral Resource Estimation Process

Criteria

Explanation

Drilling

A combination of RC drilling and diamond drilling has been used to define the resource with the drill spacing varying between 100 metres x 50 metres to 200 metres x 50 metres. All drill holes completed by Berkeley were surveyed using DGPS.

Sampling

RC drill holes were sampled on one metre intervals using standard splitting and sampling procedures. Diamond drill holes were sampled on one metre intervals or intervals suitable to the logged geology.

Assays

All samples were submitted to a registered laboratory for uranium analysis by XRF (pressed powder) techniques, with the inclusion of appropriate blanks and standards. Where no assays are present down-hole radiometric data was composited on one metre intervals to ensure continuous data in each drill hole. While correlations between gamma data and assay data suggest that the gamma data underestimates the assay data, no adjustment was made to the gamma data used in the resource estimate.

Estimation techniques

The standard Berkeley methodology for estimating resources was applied with the creation of a geologically interpreted wireframe to encompass all mineralisation and a block model generated. Ordinary kriging was applied to estimate the U3O8 grade into each block using one metre composites.

Cut-off Parameters

The resource estimate has been reported using a 200 ppm U3O8 lower cut-off grade.

Bulk Density

Bulk density measurements have been taken on regular intervals on diamond drill core and geologically classified as strongly weathered, partially weathered and unweathered sediments. The resource blocks are defined as being in one of these three domains and assigned the respective density.

Classification

Due to the wide drill spacing for this style of vein-hosted uranium deposit the resource category is Inferred.

 

 

 

 


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