The Geology of the Endeavor Mine - an update -

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The Geology of the Endeavor Mine- an update -

• Peter Nicholson, Don Smith and Vanadis Mares

CBH Resources Limited
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History

• 1973 Discovered by EZ - bullseye mag anomaly
  with coincident Pb/As in soil
• 1983 Production begins from Elura Mine
• 1998 Intersection of mineralisation close to
  limestone at 1200m depth
• 2003 Purchased by CBH Resources Ltd. and renamed
  Endeavor Mine

CBH Resources Limited
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Production

• At June 2005
• Resources 17.7 MT
• 4.9 Pb, 8.7 Zn, 69 g/t Ag
• Reserves 11MT
• 4.9 Pb, 7.9 Zn, 66 g/t Ag
• Mine Production 24MT
• At present, production is ramping up to a rate of
  1.4 MT per annum

CBH Resources Limited
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Cobar Basin Mineralisation

• Generally polymetallic discordant veins hosted by
  siliciclastic turbidites
• Often in anticlines adjacent to competent
  lithologies
• Concentration of shows within structural corridor
  on E margin
• Transfer structures often present
• Largest deposits adjacent to basement protrusions
  into Basin

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Cobar Basin Mineralisation
The Peak
after Lawrie and Hinman 1998
500m
25640E
Rhyolite
Rhyolite
100m

• Generally polymetallic discordant veins hosted by
  siliciclastic turbidites
• Often located in anticlines adjacent to competent
  lithologies, e.g. limestone at Endeavor, rhyolite
  at The Peak, basic intrusive at Louth

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Structural Corridor
Cobar TMI Corridor is defined by mineralisation,
coincides with magnetic, gravity and geological
fabric
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Basement Protrusions
Cobar Basin Gravity Basement protrusions
indicated by gravity low anomalies and doming of
sediments
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• Cobar Basin
• Summary

structural corridor
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surface
sulphide stringers

• Endeavor Mine
• 7000N Cross Section

• 1200m siliclastic turbidites overlie limestone
  breccia
• Tuffs and two shale rich units markers
• South plunging anticline
• Early concordant and steep NNW faults
• Later steep N and NNE faults cut mineralisation

upper shale
9600RL
high-grade massive sulphide
lower shale
limestone
4900E
200m
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surface

• Endeavor Mine
• 7000N Cross Section
• Above 900m depth within anticline axis
• Truncates against shales
• Offset by N and NNE faults
• Sub vertical pipes within sheet
• Below 900m mineralisation bifurcates into two
  concordant zones that dip down anticlinal limbs
• Alteration
• Siderite clots and replacement forms halo several
  tens of metres around sulphide stringers.
  Preferentially replaces siltstone/sandstone
• Silicification and chloritisation intense in
  places

sulphide stringers
upper shale
9600RL
high-grade massive sulphide
lower shale
limestone
4900E
200m
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• Endeavor Mine
• 7075N Cross Section

Sandstone/shale
Lower shale
PO/PY/SIPY
VEIN 6-10PbZn
MINA 1-6PbZn
20m
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• Endeavor Orebody 9400RL plan
• Mineralisation in anticline axial plane
• Low-grade halo of sulphide stringers
• open along strike
• N and NNE faults truncate

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• Endeavor Mine Schematic
• Long Section

7000N
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Metal Zonation (long section slices)
gt9.0
gt0.6
0.04-0.1
1.0-2.0
Zn
Cu
Ag
100m
Cu

• Zinc Highest grade (8-10) in centre of pipes. Pb
  similar
• Silver Concentrated on upper/outer margins. Up to
  1000ppm
• Copper Up to 4 in small pods at base of pipes

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Metal Zonation - Cross Section 7080N
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Endeavor Mine Mineralisation Textures

• Axial Plane Mineralisation
• Massive textured and banded
• Banding sub parallel to contacts
• Often rapid transition from altered sediments
• Concordant Mineralisation
• Quartz-siderite veins along strike
• Low grade material composed of discordant veins
  and concordant replacements

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Mineralisation Textures
Face showing near-horizontal bedding in lower
shale unit with siltstone layers replaced by
pyrite, sphalerite galena Vein at the centre
of the photo sub parallels cleavage measures
20cm
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Mineralisation Textures
20 mm
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Mineralisation Textures
sphalerite
galena
sphalerite
10 mm
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Endeavor Mine Exploration

• Massive sulphide zones open up dip, down dip to
  N of current workings
• Mineralisation near limestone contact to be
  tested from W
• High metal prices have encouraged investigation
  into mining zones of stringer mineralisation
• Stringer zone open along strike to N S, down
  dip on both limbs. May contain more massive
  sulphide or lower grade zones

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Endeavor Mine Exploration
Massive Sulphide
sulphide open
sulphide stringers open
stringers open
sulphide stringers open
Limestone
Contact mineralisation partially defined
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Endeavor Mine Exploration
Planned drillholes

• Drilling planned to
• test mineralisation
• adjacent to the
• limestone contact

limestone
lower shale
50m
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Endeavor Geology Update - Summary

• Mineralisation localised in zones of competency
  contrast on both regional and local scale
• Shale-rich sequences appear to truncate axial
  plane mineralisation
• Concordant mineralisation may be important
• Better understanding of mineralisation controls
  and high metal prices has expanded exploration
  opportunities

CBH Resources Limited