Consolidated Minerals Limited (“CML”) is an independent ... · manganese and chromite ore...
Transcript of Consolidated Minerals Limited (“CML”) is an independent ... · manganese and chromite ore...
Consolidated Minerals Limited (“CML”) is an independent private company incorporated in Jersey. CML is a manganese and chromite ore producer with operations in Australia and Ghana, complemented by a trading-arm based in Singaporearm based in Singapore.
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should not be copied or disclosed to any other person without the express authorisation of Consolidatedshould not be copied or disclosed to any other person without the express authorisation of Consolidated Minerals Pty Ltd.
No express or implied representation or warranty is made as to the fairness, currency, accuracy, completeness, reliability or reasonableness of this presentation, or any opinions, conclusions and forward-looking statements it contains.
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ContentsContents
Previous workC t d Case study area Location + design AEM system specificationsAEM system specifications Data profiles and channel grids CDI processing
Conclusions
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LocationLocation
Woodie Woodie Manganese mine Woodie Woodie Manganese mine is located in the East Pilbara region of Western Australia
The mine consists of approximately 100km2 of mine corridor and 5500km2 ofcorridor and 5500km2 of greenfields area outside of this corridor
Pilbara Manganese supplies high-grade ore to the international
l i dsteel industry
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StratigraphyStratigraphy Manganese in the Woodie Woodie region
is hosted by Carawine Dolomite chertis hosted by Carawine Dolomite, chert breccia, and the overlying Manganese Subgroup sedimentary rocks
Orebodies show a range of orientations, from stacked bedding-parallel lenses (stratabound) to steeply dipping or(stratabound) to steeply dipping or plunging bodies (fault hosted)
A d it i i 0 5Mt (0 2 Average deposit size is 0.5Mt (0.2 –5.5Mt), generally 50-100m wide, 100-600m long and deepest ore zones extend 200m below surface (open at depth)200m below surface (open at depth)
From Jones, 2011
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From Jones, 2011
Physical PropertiesPhysical Properties Manganese (Mn) is often conductive compared to host rocks
Chert and dolomite are resistive Chert and dolomite are resistive Permian clays and Jeerinah formation black shales are conductive
and must be accounted for during processing/interpretation
Conductivity response related to mineralisation can depend on Mn mineral type, grade and iron content
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Initial AEM Surveying A HoisTEM survey was flown by GPX surveys over the Woodie Woodie
mine corridor in 2002
Initial AEM Surveying
mine corridor in 2002 Discrete targets were interpreted and a number tested by drillholes Chris D deposit was an EM discovery – mineralisation below 30-50m
of conductive coverof conductive cover
pth
(m)
A BCDI Depth Slice 50m
From Hashemi, 2005D
ep
200m
Jeerinah Shale
AJeerinah Shale
Chris D
B
AEM surveys were flown over regional project areas based on the success of targets from the HoisTEM survey500m
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Case Study AreaLocation Bee Hill
Regional project area Regional project area Approximately 60km SW of
Woodie Woodie mine
Woodie Woodie Mine
Case study area chosen based on detailed geological mapping, previous drilling and geophysical surveying
Bee Hill Project Area
Case Study Area
15km
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15km
Case Study Area Geology
CfCf
ACxs
PMsx
PMssm
Acx
C
Tsg
PDod 500m
N
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Case Study Area AEM Systems Three heli-borne AEM systems were flown over the case study area
RepTEM in May 2008 by GPX Surveys RepTEM in May 2008 by GPX Surveys VTEM in May 2009 by Geotech Airborne XTEM in November 2009 by GPX Surveys
RepTEM VTEM XTEM
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Case Study Area System Specifications
RepTEM VTEM (12) XTEMMoment (Am2) 112 000 400 000 102 000Duty Cycle (%) 25 36.7 25W f h S T id l S
Power
Waveform shape Square Trapezoidal SquareRamp Off (µs) 40 1340 45Data Channels 21 28 (35*) 30
Transmitter turn off time
Data Channels 21 28 (35 ) 30Along line sampling (m) 9 2 9
Historically, systems with resolution in the early times were considered ideal for near-surface, moderately conductive bodies
New geology model suggested deeper bodies and structural relationship important
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Case Study Area Survey Specifications Flight line direction for all systems was E-W, perpendicular to geology
and structures of interestand structures of interest Line spacing was determined for each system based on the transmitter
parameters and resolution of manganese targets80m for RepTEM and XTEM 80m for RepTEM and XTEM
100m for VTEM
Traditionally, AEM systems measure the time rate of change of the magnetic field (dB/dt) = RepTEM and XTEM
VTEM calculates the B-field data from dB/dt, equivalent to a direct , qmeasurement of the magnetic field
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Case Study AreaProspect of Interest
-38000m
-39000m
L2740 RepTEML19940 VTEML40100 XTEM
-40000m
L40100 XTEM
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
500m
N
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Case Study Area Data Profiles
RepTEM XTEM
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Case Study Area Data Profiles
VTEM dB/dt - original VTEM dB/dt - reprocessed
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Case Study Area Data Profiles
VTEM B-field - original VTEM B-field - reprocessed
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Case Study Area Channel Grids Each time channel was gridded for the three systems, including both B-
field and dB/dt original and reprocessed data for the VTEM surveyfield and dB/dt, original and reprocessed data for the VTEM survey Earliest time channel available (not noise) Mid-time channel
L i h l (b f i l idd b i ) Latest time channel (before signal over-ridden by noise)
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RepTEM Ch 02 (~67.5 µs) XTEM Ch 01 (~114 µs)
VTEM dB/dt original Ch 08 (~83 µs)
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM dB/dt reprocessed Ch 01 (~10 µs)( )
VTEM B-field original Ch 08 (~83 µs)
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM B-field reprocessed Ch 01 (~10 µs)
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1km
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
RepTEM Ch 08 (~507 µs) XTEM Ch 08 (~316 µs) 12
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM dB/dt reprocessed Ch 16 (~339 µs)VTEM dB/dt original Ch 20 (~682 µs)
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM B-field reprocessed Ch 16 (~339 µs)VTEM B-field original Ch 20 (~682 µs)-1
9000
m
-200
00m
-210
00m
-220
00m
-230
00m
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1km
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
RepTEM Ch 13 (~2278 µs) XTEM Ch 23 (~3482 µs)
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM dB/dt original Ch 31 (~4620 µs) VTEM dB/dt reprocessed Ch 31 (~4620 µs)
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
VTEM B-field original Ch 31 (~4620 µs) VTEM B-field reprocessed Ch 31 (~4620 µs)
20
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
-190
00m
-200
00m
-210
00m
-220
00m
-230
00m
1km
Case Study Area Conductivity Depth Imaging EM data from each system was inverted using EMFlow software to
produce a conductivity depth modelproduce a conductivity depth model Equivalent lines from each system windowed to the prospect of interest
are presentedL2740 RepTEM L2740 RepTEM
L19940 VTEM L40100 XTEM
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170.10.0
-50.0
289.40.0
-50.0
10.0
1.0
-100.0
-150.0
-200.0
10.0
1 0
-100.0
-150.0
-200.0
0.1-250.0
-300.0RepTEM
1.0
0.1
-250.0
-300.0XTEM
-50.0
-100.0
150 0
0.0 522.3
10.0
-50.0
-100.0
0.0 581.7
10.0
-150.0
-200.0
-250.0
-300.0
1.0
0.1
-150.0
-200.0
-250.0
-300.0
1.0
0.1
242.4-50.0
0.0
50 00.0 368.4
VTEM dB/dt
VTEM dB/dt reprocessed
300.0
10.0
1.0
0.1
-100.0-150.0
-200.0
-250.0
-50.0-100.0-150.0
-200.0
250 0
10.0
1.0
0 1-300.0
VTEM B-field 22
-250.0
-300.0VTEM B-field reprocessed
0.1
1km
Case StudyDrilling
W E
Proterozoic shale with Mn ± Fe
7m @ 32% Mn, 20% Fe4m @ 37% Mn, 19% Fe
CDI anomaly outline
Chert/highly silicified dolomite
21m @ 32% Mn, 19% Fe10m @ 39% Mn, 16% Fe
50m
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50m
Fig Tree a quick comparisonFig Tree – a quick comparison Project area approximately 40km South of Woodie Woodie mine VTEM survey flown in 2009 using 100m line spacing with lines oriented VTEM survey flown in 2009 using 100m line spacing with lines oriented
perpendicular to major structures and lithology trends
D i l i i h l dB/d d B fi ld Dominantly resistive host geology, dB/dt and B-field responses very similar
B-field 1km
dB/dt
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dB/dt 1km
ConclusionsConclusions Three time domain airborne EM systems flown over a case study area
with known manganese mineralisationwith known manganese mineralisation Each system showed a discrete anomalous response in channel time
data and a conductor in the CDI related to Mn
High signal to noise and the B-field option of the VTEM system provides an advantage over traditional dB/dt systems shows target into late time channels when conductive overburden
response has decayed
Geology of the survey area should be considered when targeting Mn using AEM Conductive overburden = B-field data for target discriminationConductive overburden B field data for target discrimination Dominantly outcropping resistive geology = dB/dt data provides
reasonable targets
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ReferencesReferences
Hashemi, A., 2005. Innovative geophysical exploration for high-grade manganese ore under regolith andHashemi, A., 2005. Innovative geophysical exploration for high grade manganese ore under regolith and sedimentary cover in the East Pilbara of Western Australia, Curtin University of Technology Doctor of Philosophy thesis, 226p.
Jones, S., 2011. Proterozoic deformation in the east Pilbara Craton and teconic setting of fault-hosted manganese at the Woodie Woodie mine, Australian Journal of Earth Sciences, 58, p. 639-673
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