Berkeley Resources Limited
28 February 2007
BERKELEY RESOURCES LIMITED
28 February 2007
Further drilling results confirm retortillo URANIUM mineralisation
The Directors of Berkeley Resources Limited (AIM: BKY.L) are pleased to advise
the results of the next four holes of its confirmatory drilling programme at the
Retortillo project in Salamanca Province, Spain.
Vertical diamond core hole RTO-002 is located some 100m south easterly along the
strike of the mineralisation from the initial hole RTO-001 (see website:
www.berkeleyresources.com.au). Vertical diamond core hole RTO-004 is located a
further 700m south easterly along strike.
These holes were designed to test the continuity and tenor of the uranium
mineralisation and confirm the results of previous drilling which tested the
area with 50m x 50m and 100m x 100m grids at least 20 years ago. As the
Retortillo mineralisation had been tested by different organisations at
different times, the current drilling programme is also checking for variations
in the historical results.
Chemical assay results for these holes include the following intersections, at a
0.02% U3O8 cut-off:
Hole RTO-002
13.5 metres @ 0.0307% U3O8 from 26.0m
1.8 metres @ 0.0635% U3O8 from 45.2m
Hole RTO-004
4.0 metres @ 0.207% U3O8 from 23.0m
8.3 metres @ 0.0706% U3O8 from 33.7m
These results continue to be encouraging for the validation of the previous
diamond and RC drilling and confirm the continuity and predictability of the
Retortillo mineralisation.
Vertical diamond core holes RTO-003 and RTO-005 were drilled within the north
western block of mineralisation defined by past work. This block is separated
from the main Retortillo mineralisation by a topographically lower zone from
which the mineralisation may have been eroded (there is currently no known
mineralisation in this area). There appear to be some differences in the tenor
of the mineralisation between the two blocks, with the NW block containing less
higher grade mineralisation in both the historical and new data.
Chemical assays are pending on holes RTO-003 and RTO-005 however, radiometric
equivalent assay results include the following intersections at a 0.02% U3O8
cut-off:
RTO-003
10.0 metres @ 0.0513% U3O8 from 11.5m
8.0 metres @ 0.0507% U3O8 from 28.0m
RTO-005
14.0 metres @ 0.0369% U3O8 from 23.0m
These results are an encouraging start to the validation of the previous diamond
and RC drilling of the NW block of the Retortillo deposit.
The correlations between the radiometric equivalent and assay uranium contents
for holes RTO-001-RTO-002 and RTO-004 are excellent, giving a high level of
confidence in the assay equivalent estimates for RTO-003 and RTO-005.
EFFECT OF APPLYING A 0.01% U3O8 CUTOFF
Given current prices for U308, and the prospect of substantial thicknesses of
continuous, shallow, oxidised, flat lying uranium mineralisation, the
forthcoming calculation of JORC compliant resources for Retortillo will consider
lower cut-offs, in addition to the standard 200ppm applied previously. Using a
0.01% U3O8 cut-off the intersections become:
RTO-002
30.0 metres @ 0.0253% U3O8 from 26.0m
RTO-003
30.5 metres @ 0.0357% U3O8 from 11.5m
RTO-004
18.0 metres @ 0.0832% U3O8 from 23.0m
RTO-005
8.0 metres @ 0.0185% U3O8 from 8.7m; and
19.0 metres @ 0.0312% U3O8 from 23.0m
For comparison, application of a 0.01% U3O8 cut-off to the previously announced
results of RTO-001 gives intersections of:
32.0m @ 0.106% U3O8 from 9.8m
28.2m @ 0.167% U3O8 from 45.8m
Hole details include:
HOLE_ID DRILLED_BY UTM_E (m) UTM_N (m) RL Inclination EOH
RTO-001 INSERSA 719315 4520537 743 -90 97.00
RTO-002 INSERSA 719402 4520455 745 -90 91.70
RTO-003 INSITU 718603 4521085 738 -90 98.20
RTO-004 INSERSA 719969 4520074 738 -90 98.10
RTO-005 INSITU 718565 4521180 738 -90 97.15
The Grid has a datum of UTM 29N ED50
The holes were geologically and radiometrically logged before being sampled (1/4
core) at approximately 1m intervals (intervals varying from 0.5 to 1.5m based on
geology) for most of the hole length. Tertiary gravels were not sampled.
Duplicate 1/4 core samples and blank samples were included. The samples were
assayed for total uranium by the Delayed Neutron Count (DNC) method at
Activation Laboratories Limited in Ontario, Canada.
The radiometric equivalent assays for holes RTO-003 and RTO-005 were calculated
based on a comparison of the results of RTO-001 chemical assay and radiometric
data by Roger Murphy (the former Chief Geologist of the Rossing uranium mine).
Measured recoveries were good and averaged 93%. Most of the small amount of core
loss was in the Tertiary cover sequence.
The geology of the holes currently being assayed is basically similar to that
previously reported for hole RTO-001. The drilling confirms the Tertiary cover
dips gently to the SE, forming a 'planar-based' wedge of sands and gravels
on-lapping the eroded shale - greywacke meta-sedimentary terrain. The
mineralisation is hosted in chiastolite spotted shales which have been sheared
and partially weathered.
Most of the visible mineralisation appears to be secondary torbernite, autunite
and pitchblende. The top of the mineralisation is sharp and strong and appears
to be related to the base of total oxidation - uppermost appearance of
sulphides. The upper section of mineralisation is a sub-horizontal zone of
secondary enrichment. Several lower intersections appear to of a more primary
nature.
An evolving model for the Retortillo deposit suggests the main higher grade zone
of mineralisation at relatively shallow depth is a result of supergene
enrichment during the long period of peneplanation and enhanced by recent
weathering and the current water table. The primary mineralisation may have a
lithological control with the entire deposit being intimately associated with a
strong structural overprint.
There are currently 2 diamond drill rigs operating at Retortillo. The current
drilling programme, together with the interpretation of assay and radiometric
data for the 272 holes drilled previously, is aimed at enabling calculation of a
JORC compliant resource.
The technical content of this report has been reviewed and approved by Mr
Peter Ellis, a Member of The Australian Institute of Mining and Metallurgy and
an employee 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.
Enquiries -Matt Syme Telephone: +61 417 906 717
Managing Director Facsimile: +61 8 9322 6558
Email: info@berkeleyresources.com.au
This information is provided by RNS
The company news service from the London Stock Exchange
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