Drilling Report
Berkeley Resources Limited
19 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 advise
the results of an upgraded resource calculation for the flagship Salamanca I
project, 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 impact
on project economics
• Resource at the main Retortillo deposit increased to 13m lbs at 615ppm
U3O8
• A maiden inferred resource of 2.9m lb at 382ppm for the new Santidad
deposit
• Reducing the cut-off from 200ppm to100ppm increases total resources
to19.6m lb
• Outstanding potential for further increases in resources from
ongoing drilling
• AMC Consultants appointed to commence scoping study for mine
development.
Further details are set out below.
Enquiries - Managing Director: Matt Syme Telephone: +61 417 906 717
Email: info@berkeleyresources.com.au
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 cutoff
Retortillo 9.6 615 13.0
Santidad 3.4 382 2.9
Zona 7 0.6 760 1.0
TOTAL 13.6 563 16.9
including the following indicated resources:
Ore Tonnes Grade (ppm Contained (Mlb U3O8) at
(Mt) U3O8) 200ppm U3O8 cutoff
Retortillo 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 cutoff
Retortillo 15.6 432 14.9
Santidad 6.7 255 3.8
Zona 7* 0.6 760 1.0
TOTAL 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 at
Salamanca 1 (based on historic ENUSA estimates) included an additional 590,000
pounds of U3O8 in 3 small deposits which are excluded from the above
calculations because detailed work has not yet commenced.
These estimates are based on data from historical drilling campaigns by the
Junta de Energia Nuclear (JEN) and Empresa Nacional Uranio S.A. (ENUSA) in the
period 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, 87
RC and diamond holes at Santidad and 7 diamond holes at Zona 7. They have been
developed by a team of in-house and consulting geoscientists with calculations
based on block modeling methods (for Retortillo and Santidad) and the polygonal
method (for Zona 7).
Background
These three deposits occur in close proximity within the Company's flagship
Salamanca I project and are located approximately 30 kilometres northeast of the
former uranium mine of Mina Fe, operated by ENUSA, and about 65 kilometres
southwest of the provincial capital of Salamanca.
The Salamanca I Project covers an area of 44,016 ha and includes several other
untested areas of uranium mineralisation and radiometric anomalies. The
Retortillo and Santidad deposits are only a few kilometres apart within the same
stratigraphic horizon. Zona 7 is located 14 kilometres to the north.
Retortillo Deposit
The original JEN drilling was restricted to the northwestern end of the deposit
on a 50 x 50m grid. After some verification drilling ENUSA initially extended
the deposit to the southeast on a 50 x 50m grid. This phase was followed by
further ENUSA drilling to the southeast and along the deposit margins on a 100 x
100m 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 drilling
to the southeast along traverses spaced at 100-200m intervals, which has
extended mineralisation by 400m; and targeted testing for geological continuity
and structural and lithological controls, particularly along the northern edge.
This work has defined the limits of the deposit, established geological
continuity of mineralisation and provided significant insights into the styles
of uranium mineralisation and their possible controls. Interestingly, Berkeley's
verification drilling generally improved grade and thickness, and the new
drilling results also revealed some significant inconsistencies in the
historical data. As a result, a more uniform data base, largely based on
Berkeley drilling and additional RC drilling, is required before any additional
upgrade of resource categories.
Retortillo consists of two main blocks of mineralisation separated by the
Retortillo Creek. The northwestern block lacks Tertiary cover and mineralisation
has been affected by weathering and erosion. The adjacent area of the
southeastern block has been similarly affected by weathering, due to a lack of
cover. However, the presence of Tertiary cover from grid line 60E is associated
with better development of supergene mineralisation. This cover increases to a
maximum of around 30m in the southeastern parts of the deposit.
The top of the uranium mineralisation is associated with the uppermost
appearance of sulphides and is generally sharp, horizontal and within 24m of the
surface. The base of mineralisation is irregular and sometimes associated with
the base of partial weathering. Mineralisation is associated with hydrothermal
sericite, pyrite +/- chlorite alteration and averages 15.5m in thickness.
Primary uranium mineralisation consists of pitchblende, coffinite and black
oxides incorporated into the main steeply dipping schistocity. A secondary
enrichment of dominantly autunite and minor torbernite occurs as an upper
sub-horizontal layer. Petrographically, uranium mineralisation is in the form of
pitchblende with very minor coffinite; secondary autunite-series mineralisation
is also present. Primary uranium mineralisation often coats pyrite grains and
occurs within fractures in pyrite.
Santidad Deposit
The Santidad deposit is located within the same package of regionally and
thermally metamorphosed Ordovician metaphyllites and located 3 kilometres to the
northwest of Retortillo. The metaphyllites contain numerous granitic and
pegmatitic sills and bodies and anomalously large chiastolitic blades of
andalusite, indicating closer proximity to the main Banobarez granodiorite
complex which outcrops to the SW. Erosion appears to have stripped the Tertiary
cover from all of the areas tested to date, which may explain the strong
supergene character of the mineralisation.
Testing of the Santidad radiometric anomaly with 87 RC and diamond holes has
identified relatively shallow secondary uranium mineralisation over a strike
length of 1.75 kilometres and widths usually in the range of 100-200 metres. It
is open along strike in both directions. Drill traverse spacing is generally
50-100m with holes at 50 metre intervals. The main block of mineralisation is
geologically continuous over a strike of 1.2 kilometres. The only visible
uranium minerals are autunite and torbernite facies, however detailed
mineralogical studies are in progress.
RC drilling accounts for about 95% of drilling to date and logging of chips
indicates that most mineralisation occurs within the oxidised zone, close to the
interface with fresh rock. The average depth to the top of mineralisation within
the 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 radiometric
anomaly measuring some 1,100m x 200m. JEN tested the area on an incomplete 50 x
50m grid, with more intense drilling within an area of about 400m x 200m which
includes the estimated resource. Berkeley has drilled 7 diamond holes aimed at
understanding the potential of the entire anomaly.
Significant mineralisation occurs within20m of surface as a flat lying layer
which tends to dip more steeply to the northeast in the northwestern part of the
anomaly. It consists of gummites and black oxides with significant torbernite
and autunite, and occurs in thermally altered biotite + chlorite spotted
schists. The mineralisation is usually 5 to 15m thick, with some intersections
in excess of 30m in the northern parts, and it appears discontinuous. The
presence of thick, very high grade, isolated intersections suggests steep shoots
at the intersection of high angle structures, but more work is required to
understand the controls on mineralisation before testing for the limits of the
deposit and the untested radiometric anomaly to the northeast.
Significant inconsistencies within the JEN drill data for the eastern half of
the radiometric anomaly and inconsistent results from Berkeley's drilling
program have precluded inclusion of these results in the resource estimate. For
example, the resources do not include the area around hole ZN7-007 where an
accumulated intersection of 18.5m at 0.125% U3O8 was recorded.
Resources for the Zona 7 deposit were estimated using a plan polygonal method
based on a shape defined by geological, geochemical and radiometric data. A
specific gravity of 2.5 was used for conversion of volume to tonnes.
Resource Estimation
Assessment and interpretation of the historical and Berkeley drilling data was
undertaken by Company geologists; assessment of radiometrics and calculation of
radiometric equivalent assays were completed by Roger Murphy (former Chief
Geologist of the Rossing uranium mine); and resource modeling was assisted by
McDonald Speijers (a consulting group with 15 years experience in resource
estimations). The resource for the Retortillo and Santidad deposits was
calculated using block modeling methods, while the Zona 7 resource was estimated
using a plan polygonal method. Resource classification has been carried out in
accordance with the JORC Code and resulted in 37% of the Retortillo deposit
being classified as indicated resources.
Grade was estimated using a calculated U3O8 value. Recent assays were total
uranium as determined by Delayed Neutron Activation by Actlabs (Canada) with
associated duplicates and blank standards. Most historic assays were
fluorometric analyses, which were used in preference to the few spectrometric
analyses. Where no chemical analyses were available, radiometric equivalent
assays were determined from downhole radiometric surveys using comparisons
between available radiometric and chemical data sets.
The block models employed block sizes of 10m x 10m x 2.5m within a wireframe
defined by interpretation of the geological and radiometric data. A variable
density was used based on measurements on selected core samples in all of the
diamond holes. This was based on depth and averaged slightly less than the
density of 2.5 used in the April 2007 resource calculation.
When ENUSA commenced exploration of the Salamanca area in the late 1970's and
early 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 by
radiometrically re-logging remnant JEN core. Although no useable drill core or
samples now exist from the JEN and ENUSA drilling, the recent diamond core
drilling by Berkeley has provided a check on both the JEN and ENUSA (diamond and
percussion) drilling. Recent drill results at least equal, or exceed, the
historical drilling in both grade and intersected widths. These new holes were
initially radiometrically logged, and subjected to geological logging, sampling
and assaying over the entire core length, or more recently to selective assaying
of zones of radiometric anomalies and the adjacent few metres of non-radiometric
material. Core recoveries were in excess of 93%.
Future Exploration
The Salamanca I project has high potential to add further resources in the
ongoing exploration program.
Further extension drilling is in progress at Santidad to confirm and clarify the
current resource model and to determine the southeast and northwestern limits of
the deposit. Subsequent to the drilling included in the resource model,
percussion drilling extended the limits of the mineralisation by 200m, to a
total strike length of around 1.75km. The Retortillo/Santidad stratigraphy
remains untested for approximately 3.5km along strike to the northwest of the
Santidad deposit, before it is truncated by granite and much of this extension
is covered by Tertiary. The stratigraphy is also untested for approximately 1km
to the southeast, before it meets the Rio Yeltes.
Additional drilling is also planned to test the area about 300 metres to the
northeast of the Santidad deposit, where further strong ground radiometric
anomalies occur on the northern limb of the synclinal structure. Initial scout
drilling in the area has encountered Santidad style uranium mineralisation.
At Zona 7 there is potential for significant additional resources and the
anomaly appears to continue for several kilometers to the northeast and link to
the previously mined La Cristina deposit.
Future drilling and exploration at Salamanca I will also benefit from the
airborne survey currently underway. This survey includes 4 channel radiometrics
and magnetics and is aimed at better defining controlling structures and host
lithologies associated with uranium mineralisation. It is expected to facilitate
the targeting of new areas with potential for mineralisation, particularly in
the large untested areas within the Salamanca I project where favourable
carbonaceous shale stratigraphy appears to extend beneath Tertiary cover.
Scoping Study
This substantial upgrading of resources, and the outstanding potential for
further increases, is likely to have a favourable impact on the potential
economics of mining at Salamanca 1. Therefore Berkeley has appointed AMC
Consultants to undertake a scoping study of the potential for mine development
at Salamanca I.
AMC are expected to complete their report by the end of the year or early in
2008.
The information in this report that relates to Exploration Results, Mineral
Resources 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 of
Berkeley Resources Limited. Mr Ellis 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'. Mr Ellis consents to the inclusion
in the report of the matters based on his information in the form and context in
which it appears.
This information is provided by RNS
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