19th Nov 2007 08:27
Berkeley Resources Limited19 November 2007 19 November 2007 STOCK EXCHANGE ANNOUNCEMENT BERKELEY INCREASES SALAMANCA I RESOURCES TO 16.9M LBS U3O8 COMMENCES SCOPING STUDY The Directors of Berkeley Resources Limited (AIM: BKY.L) are pleased to advisethe results of an upgraded resource calculation for the flagship Salamanca Iproject, which includes the Retortillo deposit and the new Santidad discovery: • Project inferred and indicated resources now total 16.9m lb of U3O8,an increase of 42% • These additional resources are expected to have a significant impacton project economics • Resource at the main Retortillo deposit increased to 13m lbs at 615ppmU3O8 • A maiden inferred resource of 2.9m lb at 382ppm for the new Santidaddeposit • Reducing the cut-off from 200ppm to100ppm increases total resourcesto19.6m lb • Outstanding potential for further increases in resources fromongoing drilling • AMC Consultants appointed to commence scoping study for minedevelopment. Further details are set out below. Enquiries - Managing Director: Matt Syme Telephone: +61 417 906 717 Email: [email protected] New Resource Estimates Results from the new calculations are as follows: At a 200ppm U3O8 cutoff, total inferred and indicated resources are: Ore Tonnes Grade (ppm Contained (Mlb U3O8) at (Mt) U3O8) 200ppm U3O8 cutoffRetortillo 9.6 615 13.0Santidad 3.4 382 2.9Zona 7 0.6 760 1.0TOTAL 13.6 563 16.9 including the following indicated resources: Ore Tonnes Grade (ppm Contained (Mlb U3O8) at (Mt) U3O8) 200ppm U3O8 cutoffRetortillo 3.8 581 4.8 At a 100ppm cut-off the total inferred and indicated resources are: Ore Tonnes Grade (ppm Contained (Mlb U3O8) at (Mt) U3O8) 100ppm U3O8 cutoffRetortillo 15.6 432 14.9Santidad 6.7 255 3.8Zona 7* 0.6 760 1.0TOTAL 22.9 389 19.6 * Zona 7 resources have been calculated at a 200ppm cut-off only. including the following indicated resources: Ore Tonnes Grade (ppm Contained (Mlb U3O8) at (Mt) U3O8) 100ppm U3O8 cutoff Retortillo 5.7 431 5.4 Note - for comparative purposes - previously published resource targets atSalamanca 1 (based on historic ENUSA estimates) included an additional 590,000pounds of U3O8 in 3 small deposits which are excluded from the abovecalculations because detailed work has not yet commenced. These estimates are based on data from historical drilling campaigns by theJunta de Energia Nuclear (JEN) and Empresa Nacional Uranio S.A. (ENUSA) in theperiod from the late 1950's to the mid 1980's at Retortillo and Zona 7,supplemented by Berkeley drilling of 72 diamond and RC holes at Retortillo, 87RC and diamond holes at Santidad and 7 diamond holes at Zona 7. They have beendeveloped by a team of in-house and consulting geoscientists with calculationsbased on block modeling methods (for Retortillo and Santidad) and the polygonalmethod (for Zona 7). Background These three deposits occur in close proximity within the Company's flagshipSalamanca I project and are located approximately 30 kilometres northeast of theformer uranium mine of Mina Fe, operated by ENUSA, and about 65 kilometressouthwest of the provincial capital of Salamanca. The Salamanca I Project covers an area of 44,016 ha and includes several otheruntested areas of uranium mineralisation and radiometric anomalies. TheRetortillo and Santidad deposits are only a few kilometres apart within the samestratigraphic horizon. Zona 7 is located 14 kilometres to the north. Retortillo Deposit The original JEN drilling was restricted to the northwestern end of the depositon a 50 x 50m grid. After some verification drilling ENUSA initially extendedthe deposit to the southeast on a 50 x 50m grid. This phase was followed byfurther ENUSA drilling to the southeast and along the deposit margins on a 100 x100m grid with final stage step-out drilling at 200m centres to the southeast. Berkeley's drilling in 2007 (essentially diamond) has had three objectives:verification drilling at 50m centres on selected traverses; extension drillingto the southeast along traverses spaced at 100-200m intervals, which hasextended mineralisation by 400m; and targeted testing for geological continuityand structural and lithological controls, particularly along the northern edge. This work has defined the limits of the deposit, established geologicalcontinuity of mineralisation and provided significant insights into the stylesof uranium mineralisation and their possible controls. Interestingly, Berkeley'sverification drilling generally improved grade and thickness, and the newdrilling results also revealed some significant inconsistencies in thehistorical data. As a result, a more uniform data base, largely based onBerkeley drilling and additional RC drilling, is required before any additionalupgrade of resource categories. Retortillo consists of two main blocks of mineralisation separated by theRetortillo Creek. The northwestern block lacks Tertiary cover and mineralisationhas been affected by weathering and erosion. The adjacent area of thesoutheastern block has been similarly affected by weathering, due to a lack ofcover. However, the presence of Tertiary cover from grid line 60E is associatedwith better development of supergene mineralisation. This cover increases to amaximum of around 30m in the southeastern parts of the deposit. The top of the uranium mineralisation is associated with the uppermostappearance of sulphides and is generally sharp, horizontal and within 24m of thesurface. The base of mineralisation is irregular and sometimes associated withthe base of partial weathering. Mineralisation is associated with hydrothermalsericite, pyrite +/- chlorite alteration and averages 15.5m in thickness. Primary uranium mineralisation consists of pitchblende, coffinite and blackoxides incorporated into the main steeply dipping schistocity. A secondaryenrichment of dominantly autunite and minor torbernite occurs as an uppersub-horizontal layer. Petrographically, uranium mineralisation is in the form ofpitchblende with very minor coffinite; secondary autunite-series mineralisationis also present. Primary uranium mineralisation often coats pyrite grains andoccurs within fractures in pyrite. Santidad Deposit The Santidad deposit is located within the same package of regionally andthermally metamorphosed Ordovician metaphyllites and located 3 kilometres to thenorthwest of Retortillo. The metaphyllites contain numerous granitic andpegmatitic sills and bodies and anomalously large chiastolitic blades ofandalusite, indicating closer proximity to the main Banobarez granodioritecomplex which outcrops to the SW. Erosion appears to have stripped the Tertiarycover from all of the areas tested to date, which may explain the strongsupergene character of the mineralisation. Testing of the Santidad radiometric anomaly with 87 RC and diamond holes hasidentified relatively shallow secondary uranium mineralisation over a strikelength of 1.75 kilometres and widths usually in the range of 100-200 metres. Itis open along strike in both directions. Drill traverse spacing is generally50-100m with holes at 50 metre intervals. The main block of mineralisation isgeologically continuous over a strike of 1.2 kilometres. The only visibleuranium minerals are autunite and torbernite facies, however detailedmineralogical studies are in progress. RC drilling accounts for about 95% of drilling to date and logging of chipsindicates that most mineralisation occurs within the oxidised zone, close to theinterface with fresh rock. The average depth to the top of mineralisation withinthe resource envelope is 8.8 metres and it averages 12.6 metres in thickness. Zona 7 Deposit The Zona 7 deposit occurs within an arcuate east-west trending radiometricanomaly measuring some 1,100m x 200m. JEN tested the area on an incomplete 50 x50m grid, with more intense drilling within an area of about 400m x 200m whichincludes the estimated resource. Berkeley has drilled 7 diamond holes aimed atunderstanding the potential of the entire anomaly. Significant mineralisation occurs within20m of surface as a flat lying layerwhich tends to dip more steeply to the northeast in the northwestern part of theanomaly. It consists of gummites and black oxides with significant torberniteand autunite, and occurs in thermally altered biotite + chlorite spottedschists. The mineralisation is usually 5 to 15m thick, with some intersectionsin excess of 30m in the northern parts, and it appears discontinuous. Thepresence of thick, very high grade, isolated intersections suggests steep shootsat the intersection of high angle structures, but more work is required tounderstand the controls on mineralisation before testing for the limits of thedeposit and the untested radiometric anomaly to the northeast. Significant inconsistencies within the JEN drill data for the eastern half ofthe radiometric anomaly and inconsistent results from Berkeley's drillingprogram have precluded inclusion of these results in the resource estimate. Forexample, the resources do not include the area around hole ZN7-007 where anaccumulated intersection of 18.5m at 0.125% U3O8 was recorded. Resources for the Zona 7 deposit were estimated using a plan polygonal methodbased on a shape defined by geological, geochemical and radiometric data. Aspecific gravity of 2.5 was used for conversion of volume to tonnes. Resource Estimation Assessment and interpretation of the historical and Berkeley drilling data wasundertaken by Company geologists; assessment of radiometrics and calculation ofradiometric equivalent assays were completed by Roger Murphy (former ChiefGeologist of the Rossing uranium mine); and resource modeling was assisted byMcDonald Speijers (a consulting group with 15 years experience in resourceestimations). The resource for the Retortillo and Santidad deposits wascalculated using block modeling methods, while the Zona 7 resource was estimatedusing a plan polygonal method. Resource classification has been carried out inaccordance with the JORC Code and resulted in 37% of the Retortillo depositbeing classified as indicated resources. Grade was estimated using a calculated U3O8 value. Recent assays were totaluranium as determined by Delayed Neutron Activation by Actlabs (Canada) withassociated duplicates and blank standards. Most historic assays werefluorometric analyses, which were used in preference to the few spectrometricanalyses. Where no chemical analyses were available, radiometric equivalentassays were determined from downhole radiometric surveys using comparisonsbetween available radiometric and chemical data sets. The block models employed block sizes of 10m x 10m x 2.5m within a wireframedefined by interpretation of the geological and radiometric data. A variabledensity was used based on measurements on selected core samples in all of thediamond holes. This was based on depth and averaged slightly less than thedensity of 2.5 used in the April 2007 resource calculation. When ENUSA commenced exploration of the Salamanca area in the late 1970's andearly 1980's they checked the earlier JEN drill core and samples by re-logging,re-sampling and re-analysing the core and/or JEN sample pulps, and byradiometrically re-logging remnant JEN core. Although no useable drill core orsamples now exist from the JEN and ENUSA drilling, the recent diamond coredrilling by Berkeley has provided a check on both the JEN and ENUSA (diamond andpercussion) drilling. Recent drill results at least equal, or exceed, thehistorical drilling in both grade and intersected widths. These new holes wereinitially radiometrically logged, and subjected to geological logging, samplingand assaying over the entire core length, or more recently to selective assayingof zones of radiometric anomalies and the adjacent few metres of non-radiometricmaterial. Core recoveries were in excess of 93%. Future Exploration The Salamanca I project has high potential to add further resources in theongoing exploration program. Further extension drilling is in progress at Santidad to confirm and clarify thecurrent resource model and to determine the southeast and northwestern limits ofthe deposit. Subsequent to the drilling included in the resource model,percussion drilling extended the limits of the mineralisation by 200m, to atotal strike length of around 1.75km. The Retortillo/Santidad stratigraphyremains untested for approximately 3.5km along strike to the northwest of theSantidad deposit, before it is truncated by granite and much of this extensionis covered by Tertiary. The stratigraphy is also untested for approximately 1kmto the southeast, before it meets the Rio Yeltes. Additional drilling is also planned to test the area about 300 metres to thenortheast of the Santidad deposit, where further strong ground radiometricanomalies occur on the northern limb of the synclinal structure. Initial scoutdrilling in the area has encountered Santidad style uranium mineralisation. At Zona 7 there is potential for significant additional resources and theanomaly appears to continue for several kilometers to the northeast and link tothe previously mined La Cristina deposit. Future drilling and exploration at Salamanca I will also benefit from theairborne survey currently underway. This survey includes 4 channel radiometricsand magnetics and is aimed at better defining controlling structures and hostlithologies associated with uranium mineralisation. It is expected to facilitatethe targeting of new areas with potential for mineralisation, particularly inthe large untested areas within the Salamanca I project where favourablecarbonaceous shale stratigraphy appears to extend beneath Tertiary cover. Scoping Study This substantial upgrading of resources, and the outstanding potential forfurther increases, is likely to have a favourable impact on the potentialeconomics of mining at Salamanca 1. Therefore Berkeley has appointed AMCConsultants to undertake a scoping study of the potential for mine developmentat Salamanca I. AMC are expected to complete their report by the end of the year or early in2008. The information in this report that relates to Exploration Results, MineralResources or Ore Reserves is based on information compiled by Mr Peter Ellis,who is a Member of The Australian Institute of Geoscientists and a consultant ofBerkeley Resources Limited. Mr Ellis has sufficient experience which is relevantto the style of mineralisation and type of deposit under consideration and tothe activity which he is undertaking to qualify as a Competent Person as definedin the 2004 Edition of the 'Australasian Code for Reporting of ExplorationResults, Mineral Resources and Ore Reserves'. Mr Ellis consents to the inclusionin the report of the matters based on his information in the form and context inwhich it appears. This information is provided by RNS The company news service from the London Stock ExchangeRelated Shares:
Berkeley Eng