Deeper High Grade Gold
26 Abril 2006 - 2:00AM
UK Regulatory
RNS Number:9934B
Ballarat Goldfields N.L.
25 April 2006
Ballarat Goldfields NL
ASX and Media release: 26 April 2006
Ballarat Goldfields discovers the control of higher grade
gold mineralisation, at depth, at Ballarat
Ballarat Goldfields NL (BGF) believes it has achieved a significant breakthrough
in its understanding of the higher grade gold mineralisation located at depth at
Ballarat East with the discovery of a large fault system, named the Blue Whale
fault.
Over the past 2 years, BGF has consistently observed, both visually and from
gold assays, that some of the deeper fault zones below the historical workings,
typically from 500m to 650m below the surface, contained higher concentrations
of gold than the shallower faults and, in many cases, the gold grades were much
higher than the historical mined grade.
Recent deeper drilling on the southern end of the Ballarat East field has
identified the large Blue Whale fault system which is interpreted to be an
important control on the location of this higher grade gold mineralisation.
The BGF geological model has successfully demonstrated that the gold
mineralisation at Ballarat East is associated with reverse faults, which
typically displace the layers of rock anywhere from 5 to 20 metres. Drilling of
these fault zones over the past 2 years has continually intersected gold
mineralisation on both the faults that were partially mined historically, and
additional faults below the historical mines.
The Blue Whale fault is interpreted to have greater movement than the faults
that were mined historically with a displacement of over 100 meters compared to
the 5 to 20 metres of movement on the upper level faults. The upper faults
appear to splay off the Blue Whale fault and have higher gold grades where they
are in closer proximity to it. The Blue Whale fault is considered to be the
source of the gold bearing fluids and hence controls the location of the higher
grade gold mineralisation.
The Blue Whale fault may also control the depth limit of gold mineralisation at
Ballarat East and is some 600 metres deep at the southern end of the Ballarat
East field and is interpreted to plunge to over 1500 metres at the northern end.
The depth extent of the current mine plan is 800 metres.
BGF is confident that this discovery will have a positive impact on the expected
gold grade to be recovered at depth from Ballarat East, however there is
currently insufficient data to quantify what the full impact may be. As a
consequence, BGF is reviewing the current mine plan and the focus of its
Ballarat East and Ballarat West exploration efforts.
Background Information
The drill hole grades (Table 1) from the faults targeted in the southern part of
the Ballarat East project area, are tabulated in descending depth order. The
cross section (Figure 2) has a geological interpretation identifying the
relative position of the faults based on the drilling information.
Grey Nurse Fault
Drill Hole From To Width(m)* Grade*g/t)**
50 Drill holes
Average Drill Hole Grade 3.9g/t
HammerHead Fault
Drill Hole From To Width(m)* Grade*g/t)**
DED153A 214.5 215 0.5 25.0
DED148B 193 197 4.0 5.14
DED156 200 206 6.0 7.7
DED156A 215 217 2.0 13.25
DED156B 205 206.5 1.5 7.9
DED158 203.3 207.3 4.0 9.12
Average 3.0 8.56
Gummy Fault
Drill Hole From To Width(m)* Grade*g/t)**
BDD021B 464.3 465.4 1.1 2.1
BED001A 428 430 2.0 2.0
BED001B 432 436 4.0 5.37
DED139 343 345 2.0 2.36
DED139A 344.7 349.9 5.2 10.9
Average 2.9 6.24
Mako Fault
Drill Hole From To Width(m)* Grade*g/t)**
BDD017 601 606.1 5.1 11.25
BDD021A 559.2 567.2 8.0 6.93
BDD025A 558.6 560.7 2.1 13.17
BDD025B 561.1 570.9 9.8 43.84
BED001B 526 529 2.8 7.58
BED003 544 546 2.0 0.32
BED003A 547 549 2.0 37.15
BED007 597 602 5.0 6.76
BED007A 586 589 3.0 0.5
Average 4.4 17.58
Mako Foot Wall Fault (immediately below the Mako Fault)
Drill Hole From To Width(m)* Grade*g/t)**
BDD017 627 630 3.0 24.92
BDD025A 580.4 585 4.6 1.01
BDD025B 578.5 590.7 12.2 23.5
BED008C 603 608 5.0 24.84
Average 6.2 19.77
Table 1 *All of the intersections reported have been adjusted for their
estimated true widths.
**Assay results are uncut.
NOTE: The diagrams relating to Figures 1 to 4 below can be viewed by following
this link;
http://www.ballarat-goldfields.com.au/investor_relations/documents/ASXreleaseBlueWhaleFaultRelease26April2006.pdf
Figure 1: Long section showing the location of the recently drilled faults
relative to the existing BGF inferred resource on the southern part of the
field.
Figure 2: Cross section showing the depth and relative location of the faults
identified by BGF.
Historical data from Ballarat has identified boundaries where the very high
grade surface gold mineralisation was found in the 1850's (Figure 3 and 4). From
known drilling data, BGF geologists have now projected the Blue Whale fault to
the surface and have discovered that its interpreted surface position
corresponds to the high grade surface boundary. The Blue Whale fault appears to
control the eastern boundary of the high grade gold mineralisation and, in
particular, it is adjacent to the famous Eureka Lead, which reputedly had one of
the highest concentrations of gold in the world.
At this stage, BGF cannot predict the full impact of the discovery of the Blue
Whale fault, other than to reveal that it will have a positive influence on the
gold mineralisation at depth, which has a higher average grade than was
previously modelled by the company. The modelled grades were based on historical
production records from the old quartz mines, none of which were in close
proximity to the Blue Whale fault zone. The discovery offers an exciting
opportunity for the future of gold mining at Ballarat, and BGF is reviewing all
available options to take advantage of it.
Figure 3: Plan view of the larger alluvial gold deposits showing where the Blue
Whale is interpreted to come to the surface.
Figure 4: Interpreted cross section of the Blue Whale and associated faults
which host the gold mineralisation at Ballarat.
It should be noted that the drilling results, in a Ballarat style of ore
deposit, will typically underestimate the overall resource available for mining
due to the coarse gold that is present. For a further explanation of the coarse
gold at Ballarat see the information sheet called "Ballarats Fine Gold and
Coarse Gold Distribution" in the Gold Projects section on the BGF website
(www.ballarat-goldfields.com.au).
Note:
The information in this report that relates to Exploration Results, Mineral
Resources and Exploration Potential is based on information compiled by Mr
Steven Olsen. Mr Olsen is an employee of Ballarat Goldfields NL, is a member of
the Australian Institute of Mining and Metallurgy and is a Competent Person
under the definition of the 2004 JORC Code. The Exploration Potential described
above is conceptual in nature, and there is insufficient information to
establish whether further exploration will result in the determination of a
Mineral Resource. Mr Olsen consents to the publication of this information in
the form and context in which it appears. The terms Exploration Results, Mineral
Resources and Exploration Potential are used in accordance with their
definitions in the 2004 JORC Code, which is available at www.jorc.org.
Further information on Ballarat Goldfields, including this release containing
all figures is available on the BGF website www.ballarat-goldfields.com.au
or contact Joel Forwood, Manager Corporate & Markets, on 03 5327 1111.
This information is provided by RNS
The company news service from the London Stock Exchange
END
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