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Coffey Mining Pty Ltd
2
Coffey Mining Pty Ltd
Review of the Geology and Exploration of the Ongombo Copper Project in Namibia – 2 November 2011
Coffey Mining Pty Ltd
3
Coffey Mining Pty Ltd
Review of the Geology and Exploration of the Ongombo Copper Project in Namibia – 2 November 2011
Table of Contents
1 SUMMARY ......................................................................................................................................................... 6
2 INTRODUCTION ............................................................................................................................................. 14
2.1 Participants ............................................................................................................................................... 14
2.2 Data Acquired ....................................................................................................................................... 15
2.3 Site and Technical Visits ..................................................................................................................... 16
3 RELIANCE ON OTHER EXPERTS .............................................................................................................. 17
4 PROPERTY DESCRIPTION AND LOCATION........................................................................................... 18
5 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES, INFRASTRUCTURE AND PHYSIOGRAPHY 20
6 HISTORY .......................................................................................................................................................... 23
6.1 B&O Minerals ........................................................................................................................................... 23
6.2 JCI Limited ................................................................................................................................................ 24
6.3 Tsumeb Corporation Limited ................................................................................................................. 25
6.4 Gold Fields Namibia Limited .................................................................................................................. 27
6.5 Comments ................................................................................................................................................ 29
7 GEOLOGICAL SETTING AND MINERALIZATION ................................................................................... 31
7.1 Regional Geology .................................................................................................................................... 31
7.2 Local Geology .......................................................................................................................................... 32
7.2.1 Local Geology ................................................................................................................................. 32
8 DEPOSIT TYPES ............................................................................................................................................ 36
9 EXPLORATION BY NCO ............................................................................................................................... 37
10 DRILLING ...................................................................................................................................................... 39
11 SAMPLE PREPARATION, ANALYSIS AND SECURITY ...................................................................... 40
12 DATA VERIFICATION ................................................................................................................................ 41
13 MINERAL PROCESSING AND METALLURGICAL TESTING ............................................................. 41
14 MINERAL RESOURCE ESTIMATES ....................................................................................................... 41
14.1 Introduction ....................................................................................................................................... 41
14.2 Geological Modelling .......................................................................................................................... 41
14.2.1 Structure ...................................................................................................................................... 42
14.2.2 Domains ....................................................................................................................................... 42
14.3 Borehole Data ...................................................................................................................................... 42
14.3.1 Sample Flagging ......................................................................................................................... 43
14.3.2 Compositing ................................................................................................................................ 43
14.3.3 Bulk Densities ............................................................................................................................. 43
14.4 Volume Modelling/Block Model Development ................................................................................ 43
14.4.1 Assumptions ............................................................................................................................. 43
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Review of the Geology and Exploration of the Ongombo Copper Project in Namibia – 2 November 2011
14.4.2 Block Size Test work .............................................................................................................. 43
14.4.3 Model Construction and Parameters .................................................................................... 43
14.5 Grade Estimation ................................................................................................................................ 44
14.5.1 Estimation Methods ................................................................................................................ 44
14.5.2 Estimation Parameters ........................................................................................................... 44
14.6 Resource Classification and Criteria ................................................................................................ 44
15 ADJACENT PROPERTIES ........................................................................................................................ 48
16 INTERPRETATION AND CONCLUSIONS .............................................................................................. 50
16.1 Data review and mineral resources .................................................................................................. 50
16.2 Exploration Potential ........................................................................................................................ 50
17 RECOMMENDATIONS ............................................................................................................................... 53
18 REFERENCES ............................................................................................................................................. 55
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List of Tables
Table 1_1 – Inferred Mineral Resources of the Ongombo Project……………………………………………11
Table 1_2 – Target size for Targets 1 and 2…………………………………………………………………….12
Table 10_1 – Borehole Results…………………………………………………………………………..……….39
Table 15_1 – Historical Production from the Otjihase Mine……………………………………………………48
Table 15_2 – Mineral Resources of the Otjihase Mine…………………………………………………………49
Table 16.2_1 – Target size for Targets 1 and 2…………………………………………………………………51
List of Figures
Figure 1_1 Matchless Belt with Major Sulphide Deposits……………………………………………………….8
Figure 1_2 Mineralization in borehole 158A on the East/Ost Shoot……………………………………………9
Figure 1_3 Plan of mineralization the Otjihase Mine……………………………………………………………10
Figure 1_5 Estimated distribution of copper grades Ongombo and exploration Targets…………………..13
Figure 4_1 – Location of NCO’s EPL 3238………………………………………………………………………19
Figure 5_1 – Ongombo Prospect Photos………………………………………………………………………..21
Figure 5_2 –Satellite image of EPL 3238………………………………………………………………………..22
Figure 6.1_1 – Boreholes drilled by B&O 1971-1973…………………………………………………………..24
Figure 6.3_1 Conductors identified by EMP survey…………………………………………………………….26
Figure 7.1_ Matchless Belt with Major Sulphide Deposits……………………………………………………..31
Figure 7.2.1_1_ Schematic Stratigraphy of the mineralized zone at Ongombo……………………………..34
Figure 7.2.1_1_ Mineralization in borehole 158A on the East/Ost Shoot…………………………………….35
Figure 9-1 NSAMT Conductivity Depth Section…………………………………………………………………38
Figure 16.2_1 Estimated distribution of copper grades Ongombo……………………………………………47
Figure 15_1 Plan of mineralization the Otjihase Mine………………………………………………………….49
Figure 16.2_1 Estimated distribution of copper grades Ongombo and exploration Targets……………….52
List of Appendices
Appendix A – Validation of Historical Data
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1 SUMMARY
Namibian Copper NL (NCO) requested Coffey Mining (Pty) Ltd to compile an Independent
Technical Report on the company’s Ongombo project near Windhoek, Namibia. The request was
to review the geology, historical data, recent exploration work by NCO, evaluate the mineral
resource potential of the property and estimate contained mineral resources with the current data.
NCO has had access to a large amount of data from exploration projects on the property
undertaken over the last 40 years. Data has been sourced from reports filed with the Namibian
Geological Survey in Windhoek. In addition there are numerous public domain documents
describing the geology and mineralization of the Ongombo property and neighboring mines.
In spite of nearly 170 boreholes having been drilled on the property, most of which intersected
copper mineralization no rigorous evaluation of the mineralization has taken place. Previous
owners undertook basic “reserve” calculations but no records exist of the methodologies and
assumptions used in the estimations and prospects on the Matchless belt.
Property Description
The NCO tenements are situated in the Khomas region of the Windhoek District of Namibia.
Figure 4_1 indicates the geographic locality of NCO’S Exclusive Prospecting License (EPL). The
area under license measures 15.781km from north to south and 12.552km from east to west and
covers an area of 14,524Ha.
The Gazania Investments Thirty Two (Pty) Ltd Joint Venture is the sole legal and beneficial
owner of EPL 3238 issued by the Ministry of Mines and Energy in Windhoek, Namibia. The EPL
is a full title right in the name of the Gazania Investments Thirty Two (Pty) Ltd JV. Partners to the
JV include the local BEE partner Starlight Investments (Pty) Ltd (15%), Avanti Resources Pty Ltd
(5%) and NCO (80%).
The Ongombo Project is located in an area of relatively well developed infrastructure on the
farms Ongombo and Ongombo West. The Ongombo Project is located 15km northeast from
Otjihase Mine and 45km from Windhoek, the capital of Namibia. The property is easily accessed
by tar road, from Windhoek which is the nearest large population centre and hosts all modern
amenities and public services.
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History
The property has been extensively explored in the past by the following companies:
B&O Minerals (1971-73) - The work consists of regional geological mapping and photo-
interpretation; blanket geochemical soil sampling (200 x 10/20 sample spacing); ground
magnetic; electromagnetic and airborne magnetic surveys; colour air photography; airborne
infra-red line scanner surveys; detailed geochemical soil sampling and rock sampling of
selected areas; percussion and diamond drilling of 68 boreholes.
JCI Limited (1975) - soil geochemistry, wagon drilling, diamond drilling (4 boreholes) and
geophysics (ground magnetometer survey and Turam survey).
Tsumeb Corporation Limited – (1980-1986) EMP surveys, regional lithogeochemical surveys
and diamond drilling.
Gold Fields Namibia Limited (1986-1994) - geological mapping, electro-magnetic (EM)
surveys, diamond drilling and a “reserve” estimation.
NCO (2007-2009) – geophysical surveys, 2 diamond drillholes.
Geology and Mineralization
The Ongombo project lies within the Matchless Member of the Kuiseb Formation, a conspicuous
assemblage of lenses of foliated amphibolites, chlorite-amphibolite schist, talc schist and
metagabbro. This belt, up to 5km wide in the Otjihase area, stretches 350km east-northeastwards
in the Southern Zone of the Damara Orogen from the Gorob – Hope (Figure 1_1) area towards
Steinhausen, north of Omitara.
The deposit is generally described as a Besshi-type massive sulphide. These are described as
thin sheet like bodies of massive to well-laminated pyrite, pyrrhotite, and chalcopyrite within thinly
laminated clastic sediments and mafic tuffs.
According to Cox and Singer (1986) the average size of Besshi-type deposits is 220,000t.
According to the calculations of Gold Field the Ongombo Project is within the top quarter of the
deposits classified as Besshi-type deposits. The average grade (50 percentile) is 1.5% copper.
The Ongombo Project, according to calculations by Gold Fields is in line with these grades.
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Three mineralized shoots are identified in the area, namely the West Shoot, the Central Shoot
and the East/Ost Shoot. The shoots plunge at about 7 degrees in a north easterly direction. The
mineralized zone is enveloped in staurolite-rich biotite schist, which contains fine to coarse
disseminated sulphide grains. The mineralized zone consists of streaky, banded and locally semi
massive granular sulphide aggregates within a quartzitic groundmass which is in places
magnetite bearing (Pentzel, 1994).
Typical mineralization at Ongombo is shown in Figure 1_2.
Figure 1_1
Matchless Belt with Major Sulphide Deposits (Breitkopf and Maiden 1988)
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Figure 1_2
Mineralization in borehole 158A on the East/Ost Shoot
The Otjihase Mine, managed by Weatherly International PLC, is an operating Copper Mine which
is immediately southwest of the current Ongombo Project.
Gossan outcrop is the surface expression of the massive sulphide mineralization. Otjihase
consists of four identified mineralized shoots, one large shoot more than 8km in length, broken by
faults, which forms the basis for the mine and three smaller ones.
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Figure 1_3
Plan of mineralization at the Otjihase Mine ( Weatherly 2011)
The average Au grade of 0.22g/t for the Inferred Mineral Resources at Otjihase compares with an
average grade of 0.29g/t Au for NCO’s 6.78m intercept in ONG08-1 on the Ost Shoot, and an
average grade of 0.38 g/t Au for NCO’s 3.3m intercept in ONG08-2 on the Central Shoot.
Mineral Resources
A geological model and mineral resource estimate for the TCL/Goldfields drilling data was
undertaken to determine the potential of the property and help plan future exploration. Two types
of estimation methods were attempted. The inverse distance weighted method was used for both
Shoots. An ordinary Kriging estimate was attempted for the Central Shoot.
The object of the estimation exercise was to evaluate the quality of the historical data and the
potential of the project and a base for future exploration. To this extent the geology was modelled
using the top and bottom contacts of the mineralized zone for volume modelling. No attempt to
calculate a “best cut” from the boreholes was made. In addition no minimum or maximum stoping
width was used to limit the volume. All mineralization is considered to be contained within the
mineralized zone with only sulphur (from pyrite) of potential interest in the waste zones. No waste
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models were constructed.
The only successful estimation so far is from the inverse distance weighting method. Only these
parameters are reported. Elements estimated are copper, sulphur, silver, zinc and bulk density.
Only copper and bulk density are available for all samples. Assays for silver are available for
most samples. There are a large number of missing assays for sulphur and zinc. These are
estimated where data exist.
Mineral Resources are classified as Inferred. There is a low confidence in the data due primarily
to the fact that the borehole data is incomplete with regards to survey data and geological detail.
Inferred resources are for copper and silver only. Zn and Au grades are very low and there are
many gaps in the data due to either lack of assay or non-reporting. However, even though these
metal values are low they are likely to represent significant credits especially gold. Sulphur is
underestimated for the East/Ost shoot also due to lack of assays in some of the drilling
campaigns.
Mineral resources for Ongombo are given in Table 16.2_1 and grade tonnage distributions in
Table 16.2_2. Distribution of copper grades is shown in Figure 16.2_1
Conclusions and Recommendations
In spite of the incompleteness of the reports and drilling data, there is sufficient data to evaluate
the potential of the property.
The Ongombo property hosts a similar style of mineralization to the neighbouring Otjihase Mine
and is a small moderate grade copper deposit with accessory silver, probable gold but with very
low zinc grades. The mineral resource estimation shows grades similar to what Otjihase is
Table 1_1
Ongombo Project
Inferred Mineral Resources of the Ongombo Project
Resource Category In situ tonnes and grade at 1% Cu cutoff
Tonnes (Millions) Cu (%) Ag (g/t) Density (t/m3)
Central Shoot 2.47 1.8 8 3.04
East/Ost Shoot 4.78 1.6 8 3.37
Total 7.25 1.7 8 3.26
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currently mining.
There appears to be reasonable potential to extend both the Central and East/Ost Shoot down
plunge to the north-east as far as the Swakop Graben on the EPL boundary. Conductivity results
show potential for another two parallel shoots but these appear as much weaker signal and the
geometry may be similar to Otjihase with a combination of well mineralized shoots and poorer
ones. Drilling has not delineated the full extent of the deposit. Addition potential lies in four areas
(Figure1_5)
The potential size of target 1 and target two may be in the order of 6Mt (Table 1_2). Parameters
in Table 1_2 are taken form the results of the Mineral Resource estimation.
Table 1_2
Ongombo Project
Target size for Targets 1 and 2
Area Length Width Thickness Density
Total tonnes Extraction ratio Est Tonnes
(Mt) Grade
(m) (m) (m) (t/m3)
Central 5,800.00 200 1.5 2.9 5,046,000.00 0.7 3.5 1.8
East/Ost 2,600.00 250 2.7 3.3 5,791,500.00 0.4 2.3 1.6
Total 5.8 1.7
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Figure 1_5 Estimated distribution of copper grades at Ongombo and exploration Targets
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2 INTRODUCTION
Namibian Copper NL (NCO) requested Coffey Mining (Pty) Ltd to compile an Independent
Technical Report on the company’s Ongombo project near Windhoek, Namibia. The request was
to review the geology, historical data, recent exploration work by NCO, evaluate the mineral
resource potential of the property and estimate contained mineral resources with the current data.
NCO has had access to a large amount of data from exploration projects on the property
undertaken over the last 40 years. Data has been sourced from reports filed with the Namibian
Geological Survey in Windhoek. In addition there are numerous public domain documents
describing the geology and mineralization of the Ongombo property and neighbouring mines.
In spite of nearly 170 boreholes having been drilled on the property, most of which intersected
copper mineralization no rigorous evaluation of the mineralization has taken place. Previous
owners undertook basic “reserve” calculations but no records exist of the methodologies and
assumptions used in the estimations and prospects on the Matchless belt. .
2.1 Participants
The Coffey Mining personnel involved in the technical review of the Ongombo Project, including
their principal areas of responsibility, are listed below:-
Kathleen Body, Coffey Mining Principal Consultant- Resources:
(Pr.Sci.Nat, BSc (Geology)
Review of exploration and drilling data, Mineral resource estimation, and Report
preparation.
Brendan Botha, Coffey Mining Exploration Manager:
BSc Earth Sciences, BSc Hons (Geology). MSc (Earth Science and Project
Management),
MSc (Mineral Resource Management), (Pr.Sci.Nat) (MGSSA)
Review of geology and exploration data, report preparation
Navin Reddy, Coffey Mining Exploration Manager:
BSc (Geology), BSc Hons (Geology). MBA, (MGSSA)
Site visit, compilation of data
Chris Fredericks, Coffey Mining Manager Africa:
BSc (Geology), FSAIMM Pr.Sci.Nat
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Peer review
Kathleen Body and Brendan Botha are registered professional natural scientists (Pr.Sci.Nat.) with
SACNASP and are “Competent Persons” as defined in the 2007 edition of the SAMREC Code
and the 2004 JORC code.
Neither Coffey Mining, nor the key personnel nominated for the work, has any material interest in
Namibian Copper NL, its subsidiaries or their mineral properties. The work, and any other work
done by Coffey Mining for Namibian Copper NL, is strictly in return for professional fees. Payment
for the work is not in any way dependent on the outcome of the work or on the success or
otherwise of Namibian Copper NL's own business dealings. As such, there is no conflict of
interest in Coffey Mining undertaking the independent CPR as contained in this document.
In compliance with the SAMREC Code, the following should be noted:
The Competent Person with the overall responsibility for this CPR is Mrs Kathleen Body, Pr. Sci.
Nat. Mrs Body is competent based on the guidelines provided in Section 4.3 of the SAMREC
code. Mrs Body is a geologist with 16 years experience in the mining industry in a variety of
commodities including stratabound copper deposits.
In compliance with the JORC Code, the following should be noted:
The Competent Person for the Mineral Resource estimate in Kathleen Body who has supervised
all aspects of the work. Mrs Body, who is registered with the South African Council for Natural
Scientific Professionals (‘SACNASP’), has sufficient experience which is relevant to the style of
mineralization and type of deposit under consideration and to the activity which she 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’. Mrs Body
consents to the inclusion in the report of the matters based on her information in the form and
context in which it appears.
2.2 Data Acquired
Data used in the review of the project and the preparation of this report was given to Coffey
Mining by NCO. NCO obtained this data from the Namibian Geological Survey. The information
consisted of reports filed by previous operators on the property and borehole core stored at the
geological survey storage facilities. In addition, relevant reports and academic work in the public
domain were used where appropriate. Reports and other sources are listed in the References
(Section 20)
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2.3 Site and Technical Visits
A site visit of three days was undertaken by Mr Navin Reddy, Exploration Manager for Coffey
Mining 7 to 10 June 2011. The purpose of the site visit was to undertake a general site inspection
and verify data from the drilling programs.
In addition to this visit, Mr Reddy has worked on a neighbouring property. Mrs Body has visited
both of the neighbouring, Otjihase and Matchless, Mines
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3 RELIANCE ON OTHER EXPERTS
Coffey Mining has based the review of the Ongombo Deposit on information largely provided by
Namibian Copper NL (NCO). This data includes third party technical reports along with other
relevant published and unpublished third party information. Coffey Mining has endeavoured by
making all reasonable enquiries to confirm the authenticity and completeness of the third party
technical data upon which this report is based. A final draft of this report was provided to NCO,
along with a written request to identify any material errors or omissions, prior to finalization.
Neither Coffey Mining, nor the authors of this report, is qualified to provide extensive comment on
legal facets associated with ownership and other rights pertaining to the Ongombo Project. Coffey
Mining did not carry out any legal due diligence confirming the legal title of Gazania Investments
Thirty Two (Pty) Ltd to the property. Coffey Mining was provided with details of the Gazania
Investments Thirty Two (Pty) Ltd JV and various MME receipts and renewal certificates. Coffey
Mining was also provided with the latest Quarterly Report and Licence Renewals which
demonstrate legal title ownership and EPL good standing.
Similarly, neither Coffey Mining nor the authors of the report are qualified to provide extensive
comment on environmental issues associated with Namibian Copper’s mineral properties.
No warranty or guarantee, be it express or implied, is made by Coffey Mining with respect to the
completeness or accuracy of the legal, environmental, metallurgical or mineral processing
information contained in third party reports. While Coffey Mining has reviewed such third party
reports and relied on certain aspects of such reports in reaching its conclusions herein, neither
Coffey Mining nor the authors of this report accept any responsibility or liability in any way
whatsoever to any person or entity in respect of information contained in such third party reports
and documents and included in this document, or any errors in or omissions from it, whether
arising from negligence or any other basis in law whatsoever.
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4 PROPERTY DESCRIPTION AND LOCATION
The NCO tenements are situated in the Khomas region of the Windhoek District of Namibia.
Figure 4_1 indicates the geographic locality of NCO’s Exclusive Prospecting License (EPL). The
area under license measures 15.781km from north to south and 12.552km from east to west and
covers an area of 14,524Ha.
The Gazania Investments Thirty Two (Pty) Ltd Joint Venture is the sole legal and beneficial owner
of EPL 3238 issued by the Ministry of Mines and Energy in Windhoek, Namibia. The EPL is a full
title right in the name of the Gazania Investments Thirty Two (Pty) Ltd JV. Partners to the JV
include the local BEE partner Starlight Investments (Pty) Ltd (15%), Avanti Resources Pty Ltd
(5%) and NCO (80%). The yearly cost for the EPL is N$2,000. All annual license fees, as
required by the Ministry of Mines, are paid up, and all quarterly statuary reporting to the Ministry
is up to date.
Under Namibian Mineral law an EPL is granted for an initial period for 3 years. At the end of the 3
year period applications may be made to the Ministry of Mines for 2 renewal periods of 2 years
each. Applications for each subsequent renewal are subject to a reduction of 25% and 50% of the
covered area, respectively. Application for renewal shall not be withheld without reason.
The EPL was extended on 16 July 2009 for its first 2-year period. The area was reduced in area
to represent the area presented in Figure 4_1. On the 3rd
June 2011 the EPL was again renewed
for a period of 2 years to 7th
November 2012, without any reduction in area. The reason is that
the mineralization at Ongombo can be expected to occur along strike and down dip along the full
length of the tenement.
There are no other encumbrances, restrictions or objections on the property known to the author.
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Figure 4_1 Location of NCO’s EPL
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5 ACCESSIBILITY, CLIMATE, LOCAL RESOURCES,
INFRASTRUCTURE AND PHYSIOGRAPHY
The Ongombo Project is located in an area of relatively well developed infrastructure on the farms
Ongombo and Ongombo West. The Ongombo Project is located 15km northeast from Otjihase
Mine and 45km from Windhoek, the capital of Namibia. The property is easily accessed by tar
road, from Windhoek to Gobabis, and then on a gravel road from the tar road up to the project
area. There is also a railway line from Gobabis to Walvis Bay, via Windhoek running parallel to
the tarred road.
The city of Windhoek is the nearest large population centre and hosts all modern amenities and
public services. In Namibia, towns and villages have municipal water and electricity. Telephone
communication is by fixed line in major centres. Mobile telephone services are available near
settlements. The Ongombo prospect is outside of the settlement areas and has no municipal
services other than the fixed line telephone service which parallels the gravel road to Midgard
(Figure 5_2) which passes through the licence area. .
The area has a hot and dry climate with maximum mean temperatures of 31°C and 15°C for
summer and winter respectively. Summer rainfall varies between 350-450mm per annum.
Prospecting can normally be conducted throughout the year although potential extreme wet
seasons between December and February can limit access.
The terrain in the Project area is gently undulating with elevations in the range of 1,600m –
2,000m amsl. The landscape is dominated by rolling hills and covered by scrub and grassland.
The Swakop River divides the EPL into two parts (Figure 5_1 and 5_2).
The main economic activity in the area is stock farming, game hunting and eco-tourism.
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Figure 5_1
Ongombo Prospect
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Figure 5_2
Satellite Image of EPL 3238
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6 HISTORY
The property has been extensively explored in the past by the following companies:
B&O Minerals
JCI Limited
Tsumeb Corporation Limited
Gold Fields Namibia Limited Not all of the information from work done by these various
companies is available and the work presented here is from various reports available
from the Ministry of Mines in Namibia.
6.1 B&O Minerals
There are no reports or information available on the exploration activities and results for the work
done by B&O Minerals. The information referred to herein is sourced from JCI Limited, Tsumeb
Corporation Limited and Gold Fields Namibia reports.
In a TCL progress report for the period June 1981 to March 1983 (Kruger, 1983) the exploration
activities conducted by B&O Minerals are listed. The work consists of regional geological
mapping and photo-interpretation; blanket geochemical soil sampling (200 x 10/20 sample
spacing); ground magnetic; electromagnetic and airborne magnetic surveys; colour air
photography; airborne infra-red line scanner surveys; detailed geochemical soil sampling and
rock sampling of selected areas; percussion and diamond drilling of 68 boreholes (Figure 6.1_1).
According to JCI Limited (Hoffmann, 1976) B&O Minerals investigated the area from 1971 to
1973. Copper mineralization was outlined in a stratabound pyrite/pyrrhotite, magnetite quartzite
association. However, the incidence of copper, together with minor to trace amounts of zinc and
silver, was found to be only of moderate grade and the tonnage reserves outlined were sub-
economic. Furthermore, drilling results suggested mineralization of ore-grade potential within the
sulphide-bearing horizons was limited and unlikely to continue with depth or along strike.
Hoffman also states that B&O Minerals calculated an ore reserve for the eastern main shoot of
mineralization. The reserves calculated (based on 0.9m% cut off) amount to 3.29 m tonnes at
1.9% Cu with an average thickness of 1.62 metres.
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Figure 6.1_1
Boreholes drilled by B&O 1971-1973
6.2 JCI Limited
JCI commenced exploration activities in the area in November 1975. The aim of the study was to
establish, more confidently, limits on the copper mineralization of economic potential delineated
by drilling and to predict any possible extensions.
Exploration activities conducted by JCI included soil geochemistry, wagon drilling, diamond
drilling (4 boreholes) and geophysics (ground magnetometer survey and Turam survey). The
results of these activities are summarized by Hoffmann (1976) as follows:
Mineralization below the Eastern Main Shoot terminates in boreholes OGB 63, 50 and
55, with no intersection made in borehole OGB 56, located in line with and down plunge
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from the axis of best sulphide mineralization, no potential at depth is expected.
For the remainder of the ore zone all the evidence compiled suggests that no significant
extensions to the main quartzite would be found
However, further drilling should be undertaken to provide a better idea of the nature of
the quartzite and the associated sulphides in the western and central portions and to
substantiate whether or not it pinches out at depth. It is also stated in the report that the
conclusions are largely based on information available from widely spaced diamond drill
boreholes (200 metre grid-spacing over the Eastern Main Shoot) and with few boreholes
located outside the main quartzite development.
6.3 Tsumeb Corporation Limited
TCL obtained the rights to the Ongombo in 1980. The work was done in two parts; the first from
1980 to 1982 and the second part from 1983 to 1986.
Apart from regional orientation soil geochemistry, exploration work carried out by TCL during the
first two year term of the grant concentrated on the Ongombo Project. Whereas the regional
geochemical work showed that little improvement of the existing B&O Mineral work was possible,
a new shoot was discovered on Ongombo Ost 140 by means of the Newmont EMP unit.
Altogether 5 EMP surveys were read covering an area of 487 hectares and a distance of 4.3km
along strike. The EMP surveys outlined conductors extending down-plunge from the gossan
(Figure 6.3_1). Surveys 1 to 3 showed anomalies which are consistent with the known
mineralization as proven by previous drilling. Survey 5 carried out on the south western extension
of the gossan outcrop revealed weak and broad anomalies which are not indicative of economic
mineralization. Survey 4 which is joined to survey 3 in the northwest, picked-up the best anomaly.
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Figure 6.3_1
Conductors identified by EMP survey (after Kruger 1009 Figure 2)
Five diamond drill boreholes were drilled on the survey 4 conductor. Drilling was initially confined
to the north-eastern part of the area. Sulphide mineralization associated with magnetite quartzite
was intersected over widths of between 1 and 2 metres with a Cu content of just below 4% in the
best parts.
The south-western boundary of the shoot was determined by drilling. In the centre of the shoot an
intersection of 0.72m at 5.86% Cu was made on the high grade/EMP trend of the new “Ongombo
East Shoot”.
Infill drilling was also done on the Ongombo Central Shoot to delineate the mineralization in the
high conductivity part of the horizon. The best intersection showed sulphide mineralization over a
3.23m width at 1.60% Cu.
During the second period of the grant period TCL revisited the regional geological mapping
(1:25,000) with a newly developed genetic model for mineralization within the Matchless
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Amphibolite Belt.
TCL also embarked on a regional chip sampling programme of Kuiseb schists to improve their
knowledge in lithogeochemical prospecting for blind mineral deposits.
Nine diamond drill boreholes were drilled (537m) at Ongombo Central Shoot. From these 9 holes
17 intersections were recovered. Based on all the available drilling data a new geological ore
reserve was calculated by means of geostatistical methods. Using a 3m% Cu cut off a reserve of
1,378,700 tonnes of 2.11% Cu with an average width of 1.8m was estimated (Schneeweiss,
1986).
A grid of 100m x 200m was drilled over the Ongombo East Shoot anomaly. Fourteen
intersections were obtained from 8 sites over the area. From the 8 sites the shape of the body
could not be delineated and additional drilling was recommended.
A preliminary ore reserve calculation was made using the contour method. About 200,000 ore
tonnes at an average grade of slightly over 2% Cu and 17ppm Ag over 1.5m was estimated.
The result from further drilling and information on any additional work done on the Ongombo
Project by TCL was not obtained.
6.4 Gold Fields Namibia Limited
Gold Fields Namibia obtained the Hoffnung Grant, which includes the Ongombo project, in June
1988 and activities continued on the property up to 1994.
Work done by Gold Fields during this period was geological mapping, electro-magnetic (EM)
surveys as well as diamond drilling.
The geological mapping did not reveal any additional information of the area. EM loop 13-14
indicated a conductor with a trend of 037°TN, which still had to be investigated by diamond
drilling.
A total of 48 diamond drill boreholes were drilled by Gold Fields between 1988 and 1991. Of
these 33 boreholes, 11 were drilled on the Central Shoot and the balance on the East Shoot and
Ost Shoot (Figure 6.4_1).
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Figure 6.4_1
Boreholes drilled by Goldfields on the East/Ost Shoot 1988-1991
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The mineral content of the boreholes were composited into a “geological grade” and “mining
grade”. The geological grade refers to the grade of the mineralized zone between the hanging
wall and footwall. The mining grade is the defined ore zone composited to a 2m thick mining
thickness.
The result of the drilling is reflected in the resource/reserve estimations for the different ore
shoots.
Central Shoot – reserves reported to be 990,000 tonnes. The figure is based on the assumption
that all the ore has a thickness of 2m with a grade of 1.5% Cu and an SG of 3.00. The average
m% Cu value of all intersections inside the ore-body is 3.30m% Cu, which translates to a grade of
1.65% Cu for the Central Shoot.
East Shoot – reserves for the East Shoot was calculated in the same manner as for the Central
Shoot. The estimated reserves are 165,000 tonnes at 3.48m%Cu or 1.74% Cu over an thickness
of 2m.
Drilling results also indicated that the East Shoot is probably the up plunge extension of the Ost
Shoot since definite similarities in lithologies exist.
Ost Shoot – The reserves estimated by Gold Fields are tentative as the tonnes are based on an
estimated length, breadth and width of the defined orebody. The eastern section of the Ost Shoot
still has to be drilled to prove or disprove tons to the east. A tonnage of 1,794,880 tonnes at
1.29% Cu was calculated for the Ost Shoot.
In 1991 Maneschijn (Petzel, 1994) gave a total ore reserve from all available data for the West
Shoot, Central Shoot and East/Ost Shoot to be 4,143,913 tonnes at 1.60% Cu, 8.92g/t Ag and
0.21g/t Au.
No further information is available on additional work done by Gold Fields.
6.5 Comments
The property was investigated by numerous parties. The basic geological exploration has been
done in great detail and as stated little improvement was made with regards to the geological
understanding by means of geological mapping and geochemistry.
CP statement regarding historical estimations:
A qualified person has not done sufficient work to classify the historical estimate as
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current mineral resources or mineral reserves”
The issuer is not treating the historical estimate as current mineral resources or mineral
reserves as defined in the 2007 edition of the SAMREC Code and the 2004 JORC code.
The historical estimates should not be relied upon as indicative of current potential
The biggest potential for exploration is the Central and Ost Shoots. Drilling is required to properly
define the extents of the two ore-bodies as well as to determine the actual resources of the two
ore bodies.
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7 GEOLOGICAL SETTING AND MINERALIZATION
7.1 Regional Geology
The Ongombo project lies within the Matchless Member of the Kuiseb Formation, a conspicuous
assemblage of lenses of foliated amphibolites, chlorite-amphibolite schist, talc schist and
metagabbro. This belt, up to 5km wide in the Otjihase area, stretches 350km east-north-
eastwards in the Southern Zone of the Damara Orogen from the Gorob – Hope (figure 7.1_1 area
towards Steinhausen, north of Omitara.
Figure 7.1_1
Matchless Belt with Major Sulphide Deposits (Breitkopf and Maiden 1988)
A genetic relationship between the pyritic deposits and the amphibolite suite was recognized by
Voit and Stollreither (1905) who suspected the rocks to be the metamorphic diabases but could
not find conclusive evidence to verify their hypothesis. Kroner (1977) interpreted the amphibolites
and lenses of serpentinite as units of geosynclinal mafic and ultramafic volcanics. Finnemore
(1978) suggested a geochemical relationship of the Matchless suite to oceanic tholeites and
pillow lavas were recognised in the field. The amphibolite layers/lenses are generally
conformable, though locally crosscutting with respect to the compositional layering in the
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enclosing Kuiseb Formation schist. No melange has been found along the belt and there is no
change in tectonic style across it, so that the feature does not appear to be a slice of upthrust
oceanic crust. The enclosing quartz-mica schists are interpreted as deep water quartzose
greywacke.
Goldberg (1976) noted that in many places the cupriferous pyrite deposits are closely associated
with layers of magnetite quartzite. Their frequent position directly below the massive sulphide
bodies between Otjihase and Gorob, together with other evidence of stratigraphic inversion, have
been interpreted to indicate that the stratabound ores are of the Besshi-type, formed initially on
the sea floor and afterwards emplaced in overturned attitude in continental margin sediments.
Killick (1983) concurred that the sequence is inverted over a distance of at least 250km, but
considers ore deposition to have occurred in situ relative to four volcanic centres spread out
along the length of the Matchless Belt. The most north-easterly of the four volcanic centres or
clusters is the Otjihase cluster which includes the Otjihase, Ongeama and Ongombo deposits.
7.2 Local Geology
A gossanous magnetite quartzite bed on the farms Ongombo West 56 and Ongombo Ost 140,
traceable for some 5km in a north-easterly direction, dips consistently 15o
to 20o
northwest, and
is conformable with the enclosing Kuiseb Formation schist. The best outcrops are on banks of the
White Nossib River which forms the common boundary between the two farms. West of the river
a zone of slumped rusty magnetite and massive limonitic gossan continues along strike for some
1,800m. The thickness of the bed varies between 1 and 2m, thinning gradually westward. Except
for two isolated outcrops, only float indicates the sub-outcrop trend of the gossan east of the
White Nossib River. Two lenticular units of more basic schist and amphibolite are present in the
sequence above and below the gossan: in this area the amphibolites of the Matchless Member
are developed over a limited width of only 1.5km.
7.2.1 Local Geology
Three mineralized shoots are identified in the area, namely the West Shoot, the Central Shoot
and the East/Ost Shoot. The shoots plunge at about 7 degrees in a north easterly direction. The
shoots are hosted within the Kuiseb Formation schists which show signs of hydrothermal
alteration in the hangingwall of the mineralized horizon. The hangingwall schist consists of a
sequence of alternating metapelitic staurolite bearing schists, garnetiferous quartz-biotite-
muscovite-chlorite schist and massive metapsammitic, locally garnetiferous quartz-biotite schist
(Pentzel, 1994). Amphibolites comprising sheared feldspathic metagabbros and chlorite
amphibole schist were also noted in the hangingwall. Their positioning and distinct character is
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used for stratigraphical correlation.
A schematic stratigraphy of the mineralized zone is given in Figure 7.2.1_1. The mineralized zone
is enveloped in staurolite-rich biotite schist, which contains fine to coarse disseminated sulphide
grains. The mineralized zone consists of streaky, banded and locally semi massive granular
sulphide aggregates within a quartzitic groundmass which is in places magnetite bearing
(Pentzel, 1994).
The semi massive mineralized quartzite bands are intercalated with weakly mineralized biotite-
and staurolite-rich schist. The sulphides occur within the schist in association with quartz lenses
or as streaks and disseminations. The bottom part of the mineralized zone generally consists of a
poorly mineralised magnetite quartzite unit which is separated from the barren footwall schist by
staurolite-rich biotite schist.
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Figure 7.2.1_1
Schematic Stratigraphy of the mineralized zone at Ongombo (Maroni 1990 in Marlow 2007)
Typical mineralization at Ongombo is shown in Figure 7.2.1_2. This shows sections of borehole
158A on the East/Ost Shoot. Additional photographs of the mineralization can be seen in
Appendix A. A typical distribution of grades is shown in Table 10_1 for boreholes ONG08_01 and
ONG08_02
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Figure 7.2.1_1
Mineralization in borehole 158A on the East/Ost Shoot
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8 DEPOSIT TYPES
TCL introduced the Besshi-model for massive sulphides as an exploration tool on the Matchless
Amphibolite Belt and this was later adopted by Gold Fields.
The following text is a short summary of the model for the Besshi-type massive sulphide
mineralization from Cox and Singer (1986).
Description: Thin sheet-like bodies of massive to well-laminated pyrite, pyrrhotite, and
chalcopyrite within thinly laminated clastic sediments and mafic tuffs.
Geological EnvironmentRock Types: Clastic terrigenous sedimentary rocks and tholeiitic to
andesitic tuff and breccia.
Locally, black shale, oxide-facies iron formation, and red chert.
Textures: Thinly laminated clastic rocks. All known examples are in strongly deformed
metamorphic terranes. Rocks are quartzose and mafic schist.
Deposit Description
Mineralogy: Pyrite + pyrrhotite + chalcopyrite + magnetite + sphalerite
Texture/Structure: Fine-grained, massive to thinly laminated ore with colloform and framboidal
pyrite. Breccia or stringer ore. Cross-cutting veins contain chalcopyrite, pyrite, calcite or galena,
sphalerite.
Alteration: Difficult to recognize because of metamorphism.Ore controls: Deposits are thin, but
laterally extensive and tend to cluster in an echelon pattern Weathering: GossanGrade and
Tonnage
According to Cox and Singer (1986) the average size of Besshi-type deposits is 220,000t.
According to Gold Fields estimates, the Ongombo Project is within the top quarter of the deposits
classified as Besshi-type.
The average grade (50 percentile) is 1.5% Cu. The Ongombo Project, according to calculations
by Gold Fields is in line with these grades.
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9 EXPLORATION BY NCO
Previous owners of the EPL area successfully employed both magnetic and electro-magnetic
surveys to identify magnetic anomalies and conductors at the Ongombo deposit, and ground
electro-magnetic surveys penetrated effectively to around 500m. Although the Ost Shoot has
historically been tested to a depth of 500m, the Central Shoot has only previously been tested to
a depth of around 300m. Consequently a ground electro-magnetic survey was considered to be
the most appropriate initial exploration tool to test the down plunge extension of the Central
shoot.
The ground electromagnetic survey over the Central Shoot was undertaken by consultants
Gregory Symons Geophysics and completed in September 2008. The initial base line clearing
and surveying was completed in late August 2008, and the 200m spaced cut lines, loops and
pegging was completed in early September 2008. The actual electromagnetic survey was
undertaken in mid-September 2008. The Time Domain EM (TDEM) survey utilized a Geonics
Protem EM receiver with Zonge GGT10 Transmitter and Zonge GDP 32 II receiver. Four large
loops measuring 600m by 800m were surveyed on 200m spaced lines and 50m spaced stations.
The loops were aligned in a north-easterly direction down plunge of the deepest historical
intercepts of copper mineralisation on the Central Shoot. The south-western boundary of the first
loop was aligned with the northeast boundary of the last historical ground EM loop surveyed by
GFN. Initial interpretation of the EM data indicates the presence of a conductor which extends
down plunge of the deepest historical intercepts of copper mineralisation on the Central shoot,
and which is aligned parallel to the north-easterly trend of the Central Shoot. However, the
strongest signal from the conductor lies up dip of the Central shoot trend, and indicates the
Central Shoot may possibly coalesce with a down dip extension of the Ost Shoot.
The result of the TDEM (time domain electro-magnetics) and NASMT (natural source audio
magneto-tellurics) indicated a previously unknown shoot, termed the Far West Shoot. The shoot
correlates with a surface gossan.
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Figure 9_1 NSAMT Conductivity Depth Section, showing the Ongombo Shoot System
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10 DRILLING
Based on the EM data work done by NCO, NCO decided to drill 2 diamond boreholes to verify
mineralization down-plunge of the historical Ost and East Shoots.
The drilling confirmed the presence of mineralization down-plunge of the Ost and Central Shoot.
The drilling also confirmed the presence of mineralization within the “inter-shoot zone” of the
Central and Ost Shoots.
The result from the drilling is tabulated in Table 10_1.
Table 10_1
Ongombo: Review of Geology
Borehole Results
BH Id East North Depth From Depth To Thickness Cu(%) Zn(%) Au(g/t) Ag(g/t)
ONG08-1 741626 7535593 402.05 402.93 0.88 0.23 0.02 0.07 <10
402.93 403.04 0.11 0.78 0.08 0.23 <10
403.04 403.1 0.06 0.27 0.06 0.06 <10
403.1 403.14 0.04 1.42 0.09 0.61 10
403.14 403.4 0.26 0.2 0.03 0.06 <10
403.4 403.46 0.06 4.24 0.17 2.47 30
403.46 403.63 0.17 0.06 0.02 0.01 <10
403.63 403.79 0.16 8.05 0.23 1.85 51
403.79 404.58 0.79 1.49 0.06 0.39 <10
404.58 405.36 0.78 1.14 0.07 0.36 <10
405.36 406 0.64 1.03 0.04 0.28 <10
406 406.38 0.38 0.16 0.02 0.06 <10
406.38 406.66 0.28 1.42 0.02 0.38 <10
406.66 407.33 0.67 0.26 0.02 0.08 <10
407.33 407.45 0.12 1.39 0.04 0.46 10
407.45 407.74 0.29 0.13 0.02 0.05 <10
407.74 408.42 0.68 0.84 0.02 0.52 <10
408.42 408.83 0.41 0.3 0.02 0.1 <10
ONG08-2 738604 7531834 197.97 198.67 0.7 0.15 0.03 0.04 <10
198.67 199.14 0.47 0.02 0.03 <0.01 <10
199.14 199.53 0.39 0.26 0.05 0.07 <10
199.53 199.9 0.37 0.38 0.03 0.15 <10
199.9 200.15 0.25 0.96 0.06 0.28 <10
200.15 200.34 0.19 0.07 0.04 0.02 <10
200.34 200.37 0.03 1.21 0.08 0.42 <10
200.37 200.68 0.31 2.73 0.15 2.94 21
200.68 201 0.32 0.55 0.05 0.16 <10
Half core samples were taken at geological and or mineralogical boundaries. The down-hole
survey results indicate that the intercepted mineralization is a very good approximation of true
width.
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11 SAMPLE PREPARATION, ANALYSIS AND SECURITY
Bagged samples of split drill core were dispatched by the drilling management consultants
Geomine Consulting Namibia to the Genalysis labs in Joburg by courier for preparation and the
pulps air freighted to Genalysis’ laboratory in Perth, Australia. Preparation in Johannesburg
consisted of jaw crushing the whole sample followed by pulverizing to a 120 gram pulp.
Copper, zinc and silver was determined by ore grade four acid digestion followed by optical
emission spectrometry (Genalysis Method code AX/OES). Gold was determined by 25gm fire
assay (Genalysis Method code FA25/AAS). The detection limits for Cu, Zn and Au is 10ppm and
for Ag it is 0.01ppm.
No quality control programme was instituted by NCO, and only the laboratory quality control
procedures were followed.
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12 DATA VERIFICATION
Coffey Mining has reviewed all the historical exploration reports as well as literature available on
the Ongombo EPL’s and neighbouring areas. The historical reports are a summary of results
obtained and do not cover methods and processes followed. Coffey Mining has reviewed
documentation prepared by NCO, of which some of the information is used in this report.
Mr Navin Reddy of Coffey Mining undertook a three day site visit to verify the processes and
methodologies applied in the field as well as to verify the drilling programme and view the
borehole core at the geological survey of Namibia. Discussions were held with NCO staff to
discuss issues pertinent to this report.
It is the opinion of the Coffey Mining that the data reviewed is adequate to report on a
reconnaissance/early stage exploration programme and an Inferred Mineral Resource.
A summary of the historical data is given In Appendix A.
13 MINERAL PROCESSING AND METALLURGICAL TESTING
No metallurgical or processing test work has been carried out by NCO.
14 MINERAL RESOURCE ESTIMATES
14.1 Introduction
A geological model and mineral resource estimate for the TCL/Goldfields drilling data was
undertaken to determine the potential of the property and help plan future exploration. Two types
of estimation methods were attempted. The inverse distance weighted method was used for both
Shoots. An ordinary Kriging estimate was attempted for the Central Shoot. However, when model
validation was undertaken errors in the borehole data were found. When these errors were
corrected, the variogram models originally used could not be replicated and this method was
abandoned. Only the inverse distance estimation results are presented.
14.2 Geological Modelling
A geological model of the entire mineralized zone was constructed from the borehole data. The
data set is incomplete and some of the information used was estimated from information in
neighbouring boreholes. Collars –where records were available actual collar coordinates were
used. Where records were not available, collar coordinates were estimated from map positions.
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Surveys - where records were available actual survey data were used. Boreholes have a very
regular and predictable deviation caused by strong and monotonous structural fabrics. Where
survey data was not available for a specific borehole, the survey data from the nearest hole was
used to predict the position of the mineralization. Deflections which were not surveyed had the
inclination increased by one degree in the direction of the borehole deviation which was typical off
a non-direction wedge at the time. Assays – assays were extracted from drilling logs and
reports. Lithology - at this stage the only lithological distinction made was between the
mineralized zone and the non-mineralized hangingwall and footwall. Because detailed geology
was missing for many of the holes and in any case has not been verified, lithological variation
within zones was not modelled. For boreholes where geology logs existed, mineralized zone as
defined was kept. For boreholes without geological logs the limits were chosen based on grades
of copper, sulphur and silver. In most cases the boundary is obvious with large
increases/decreases in grade between neighboring samples.
14.2.1 Structure
The deposit is structurally simple consisting of two or more linear pencil shaped shoots which lie
within stratabound copper and iron sulphides. The Ost Shoot represents the down-plunge
extension of the East shoot. The shoots lie within a planar zone, which parallels the dip of the F2
penetrative fabric (main schistocity or foliation). The L2 lineation also lies within this plane and it
is this L2 extension direction, which controls the mineralisation. This lineation is well exposed at
the surface at Ongombo. Shoots and the L2 lineation plunge about 7 degrees to the northeast,
whilst the F2 fabric and stratabound sulphides dip about 15-20 degrees to the northwest.
Modelled features are the Central Shoot and East/Ost Shoot. It is possible that a small portion of
a third shoot was intersected in one borehole to the northwestt of the Central Shoot. The East
and Ost shoots have been combined as a single unit. Geologically they appear similar. The strike
change may be the result of a general change in attitude of the strata or minor faulting. A similar
feature is seen at the neighbouring Otjihase Mine (Section 15). There may be a loss in continuity
due to small-displacement sub-vertical faulting. However, with the wide borehole spacing and
lack of detailed borehole logging, the presence and extent of these faults is not known.
14.2.2 Domains
Domains are only the two shoots. Smaller domains have not yet been established.
14.3 Borehole Data
Borehole data is from the records of Tsumeb Corporation Limited and its owner in the late 1980’s-
mid1990, Goldfields Namibia Limited. A discussion of the data is given in Appendix A. Borehole
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data is used as is. The only corrections are in the survey data where obviously erroneous
readings were either removed or corrected.
14.3.1 Sample Flagging
Sample flagging for compositing and estimation is simple. All samples are flagged as
hangingwall, mineralized zone or footwall. No attempt has been made to subdivide the
mineralized zone. Better and more complete logging is needed for this step.
14.3.2 Compositing
Boreholes were not composited for inverse distance estimation but were weighted by sample
length to account for the different sample sizes. For the kriged estimate of the Central Zone
samples in the mineralized zone were composited to 40cm as used in the variograms modelling.
14.3.3 Bulk Densities
Bulk densities were estimated directly. All assays for copper also had associated bulk density
measurements. No cutting or capping was applied. Only two measurements were removed from
the database because of obvious errors (probably due to typing errors). There is a weak
correlation of density with copper grade.
14.4 Volume Modelling/Block Model Development
14.4.1 Assumptions
The object of the estimation exercise is to evaluate the quality of the historical data and the
potential of the project and a base for future exploration. To this extent the geology was modelled
using the top and bottom contacts of the mineralized zone for volume modelling. No attempt to
calculate a “best cut” from the boreholes was made. In addition no minimum or maximum stoping
width was used to limit the volume.
14.4.2 Block Size Test work
Borehole spacing varied from 50m x 100m to greater than 400m. Declustering exercise was
undertaken to look at the effect of block size on the estimation. In the unrotated coordinate
system there was very little difference between block sizes of 50 and 100m or block thickness of
2-5m. A block size of 50m x 50m x 8m was chosen in order to show the variability in the deposit
where borehole spacing was closest.
14.4.3 Model Construction and Parameters
Each shoot was modelled as a separate entity for separate estimations. Block models built on a
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common prototype are only combined for display purposes. The model was constructed using the
UTM WGS84 grid coordinates and built in Datamine software. All mineralization is considered to
be contained within the mineralized zone with only sulphur (from pyrite) of potential interest in the
waste zones. No waste models were constructed.
14.5 Grade Estimation
14.5.1 Estimation Methods
The only successful estimation so far is from the inverse distance weighting method. Only these
parameters are reported. Elements estimated are copper, sulphur, silver, zinc and bulk density.
Only copper and bulk density are available for all samples. Assays for silver are available for
most samples. There are a large number of missing assays for sulphur and zinc. These are
estimated where data exist. All samples are weighted by sample length as well as distance from
the estimation point.
14.5.2 Estimation Parameters
Search volumes were determined by borehole spacing. Three search volumes were used 100,
200 and 400m in the plane of mineralization and 10, 20 and 40m thick. The search ellipse was
rotated to the plunge of the mineralization N30Em 7 °.
The two smaller volumes were to estimate the closely spaced boreholes. Blocks were estimated
on successive passes so that estimates used the minimum volumes. The estimation allowed for
up to 50 samples per block. In practice this did not exceed 20 and half of the blocks were
estimated with less than 5 samples, effectively placing the resource classification in the Inferred
category.
All elements were estimated separately.
14.6 Resource Classification and Criteria
Mineral Resources are classified as Inferred. There is a low confidence in the data mostly
because the borehole data is incomplete with regards to survey data and geological detail.
Inferred resources are for copper and silver only. Zn and Au grades are very low and there are
many gaps in the data due to either lack of assay or non-reporting. However, even though these
metal values are low they are likely to represent significant credits especially gold. Sulphur is
underestimated for the East/Ost shoot also due to lack of assays in some of the drilling
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campaigns.
Mineral resources for Ongombo are given in Table 16.2_1 and grade tonnage distributions in
Table 16.2_2. Distribution of copper grades is shown in Figure 16.2_1
East/Ost Shoot has higher grades than the Central Shoot and the mineralized zone is thicker with
blocks estimated with a larger number of samples. Maximum block thickness for the Central
Shoot is 5m and for the East/Ost shoot 7.8m.
Table 16.2_1
Ongombo Project
Inferred Mineral Resources of the Ongombo Project
Resource Category In situ tonnes and grade at 1% Cu cutoff
Tonnes (Millions) Cu (%) Ag (g/t) Density (t/m3)
Central Shoot 2.47 1.8 8 3.04
Est/Ost Shoot 4.78 1.6 8 3.37
Total 7.25 1.7 8 3.26
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Table 16.2_2
Ongombo Project
Grade tonnage distribution of Inferred Mineral Resources of the Ongombo Project
Resource Category
In situ tonnes and grade
Cut-off grade Cumulative Tonnes Cu (%) Ag (g/t) Density (t/m3)
Central Shoot 0 3370000 1.51 9 2.9
0.5 3157000 1.59 9 3.04
1 2475000 1.79 8 3.04
1.5 1143000 2.35 11 3.08
2 601000 3.02 13 3.19
2.5 360000 3.53 16 3.25
3 209000 4.08 19 3.26
3.5 197000 4.14 19 3.27
4 155000 4.23 18 3.28
4.5 5381 4.59 23 3.24
5 275 5.14 23 3.29
Est/Ost Shoot 0 10245000 1.17 7 3.19
0.5 9807000 1.2 7 3.29
1 4780000 1.59 8 3.37
1.5 1783000 2.23 12 3.48
2 779000 2.79 15 3.8
2.5 474000 3.16 17 4.04
3 317000 3.38 21 4.39
3.5 54000 4.19 12 3.3
4 23000 5 12 3.33
5 12000 5.68 10 3.29
6 4204 6.41 7* 3.25
6.5 1821 6.93 7* 3.26
7 16 7.39 40 3.31
* Estimate may be low due to missing assays
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Figure 16.2_1
Estimated distribution of copper grades Ongombo
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15 ADJACENT PROPERTIES
The Otjihase Mine, managed by Weatherly International PLC, is an operating Copper Mine which
is immediately southwest of the current Ongombo Project.
The historical production from Otjihase is tabled in Table 15_1. For comparative purposes the
mineral resources of the Otjihase Mine are tabled in Table 15_2 (www.weatherlyplc.com,
Weatherly 2011). An improvement in the average grade of the Cu, Ag and Au is consistent with
improved resource category. The average Au grade of 0.22g/t for the inferred resources at
Otjihase compares with an average grade of 0.29g/t Au for NCO’s 6.78m intercept in ONG08-1
on the Ost Shoot, and an average grade of 0.38 g/t Au for NCO’s 3.3m intercept in ONG08-2 on
the Central Shoot.
Table 15_1
Ongombo Project
Historical Production from the Otjihase Mine (Schneider G.I.C and Seeger K.G., 1992).
Year Ore (t) Cu Concentrate (t) Pyrite Concentrate (t)
1980 5037
1981 205634 14242 26772
1982 774060 61192 108818
1983 756996 53322 118239
1984 844049 49890 172315
1985 832741 55006 174363
1986 867723 61331 189451
1987 546868 38328 120260
1988 831570 55789 226682
1989 763542 49448 196532
1990 630497 34138 138924
1991 651797 34498 127119
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Table 15_2
Ongombo Project
Mineral Resources of the Otjihase Mine
Resource Category In situ tonnes and grade
Tonnes Cu (%) Ag (g/t) Au (g/t)
MEASURED 3543518 2.41 9.05 0.43
INDICATED 2816936 1.99 6.73 0.35
INFERRED 4729622 1.49 6.34 0.22
TOTAL 11090076 1.91 7.3 0.32
The local geology of the Otjihase Mine is presented in Figure 15_1. Gossan outcrop is the
surface expression on the massive sulphide mineralization. Otjihase consists of four identified
mineralized shoots, one large shoot more than 8km in length, broken by faults, which forms the
basis for the mine and three smaller ones.
Figure 15_1
Plan of mineralization at the Otjihase Mine ( Weatherly 2011)
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16 INTERPRETATION AND CONCLUSIONS
16.1 Data review and mineral resources
In spite of the incompleteness of the reports and drilling data, there is sufficient data to evaluate
the potential of the property. The Matchless Amphibolite belt is a well know geological feature and
has been extensively studied. Along with the academic work, substantial exploration has been
carried out in the past and the neighbouring property has an operating mine which has a similar
style of mineralization. The Ongombo property hosts a similar style of mineralization to the
neighbouring Otjihase Mine. The geometry of the Ongombo deposit should be fairly predictable
and can be extrapolated beyond the current drilling for several hundred metres. Both the logged
lithologies and the assay results appear reasonable for the deposit type. At this stage the drilling
data can be used to estimate an Inferred Mineral Resource however, the lack of downhole survey
data for the boreholes leaves too large an uncertainty in the positions of the mineralized
intersections for a higher classification. There appears to be reasonable potential to extend both
the Central and East/Ost Shoot down plunge to the north-east as far as the Swakop Graben on
the EPL boundary. The NSAMT Conductivity results show potential for another two parallel
shoots but these appear as much weaker signal and the geometry may be similar to Otjihase with
a combination of well mineralized shoots and poorer ones. The Ongombo deposit is a small
moderate grade copper deposit with accessory silver, probable gold but with very low zinc
grades. The mineral resource estimation shows grades similar to those that Otjihase is currently
mining. East/Ost Shoot has a lower overall grade than the Central Shoot at a 1% copper cut off
and the East/Ost Shoot has large low-grade tonnages which the evaluated portion of the Central
Shoot does not have.
16.2 Exploration Potential
One of the main characteristics of the deposits in the northern Matchless Belt is that they have
mineralization developed in shoots of substantial length. The neighbouring Otjihase mine has
mineral resources defined over a 9 km length and the deposit may extend further. The Matchless
deposit to the southwest has shoots of several kilometres in length, also not fully evaluated.
Evaluation of the geology and mineral resources of Ongombo suggest that this same
characteristic is present at Ongombo. Drilling has not delineated the full extent of the deposit.
Addition potential lies in four areas (Figure16.2_1)
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Target 1 - The highest grades from the mineral resource estimation at the northern most end of the OST
shoot
The down plunge extension of the Ost Shoot – beyond 14,300E is essentially untested. Only 4 drill holes
exist northeast of Section 14,300E. These include ONG171 on section 14,500E, which reported 9.53m%
Cu; ONG155 and NCO borehole ONG08-1 on section 14,700E, which reported 1.62% Cu and 4.01m%
Cu, respectively; and ONG154 on section 14,900E which reported 1.33m% Cu. Modelled grades for the
East/Ost Shoot are highest in this area. The strike length of the zone between sections 14,300E and
16,900E is 2,600m.
Target 2 - the down plunge extension of the Central Shoot parallel to the East/Ost Shoot the strike length
of the zone between sections 11,100E and 16,900E is 5,800m.
Target 3 - the up-dip extension of historical mineralisation defined between sections 13,500E and
14,500E on the East/Ost Shoot – this zone represents a significant portion of the mineralisation on the
Ost shoot and all sections are open up-dip
Target 4 - the zone between the Central Shoot and the East/Ost Shoot between sections11,100E and
11,900E. The strike length of the zone linking the Central shoot to the Ost shoot between sections
11,100E and 11,900E is 800m. NCO EM data and NCO hole ONG08-2 and the mineral resource
estimation all show that the Central Shoot and the Ost Shoot locally coalesce. The continuity of
mineralisation between the historical ore shoots (the coalescing of ore shoots) could substantially
increase the tonnage target potential at Ongombo.
The potential size of Target 1 and Target two may be in the order of 6Mt (Table 16.2_1. Parameters in
Table 16.2_1 are taken form the results of the mineral resource estimation.
Table 16.2_1
Ongombo Project
Target Size for Targets 1 and 2
Area Length(m) Width (m) Thickness (m) Density (t/m3) Total tonnes Extraction ratio Est Tonnes (Mt) Grade
Central 5800 200 1.5 2.9 5046000 0.7 3.5 1.8
East/Ost 2600 250 2.7 3.3 5791500 0.4 2.3 1.6
Total 5.8 1.7
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Figure 16.2_1
Estimated distribution of copper grades at Ongombo and exploration targets
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17 RECOMMENDATIONS
There is sufficient potential on the Ongombo property to recommend additional work to evaluate
the mineral potential.
The following tasks need to be done as soon as possible;
Re-logging of all boreholes for which core is available
Find and resurvey all borehole collars to check locations
Create a detailed stratigraphic profile for the property
Remodel the geology with the revised stratigraphic interpretation
Re-evaluate the NSAMT survey to see if additional work needs to be done
A detailed exploration plan has not been supplied to Coffey by NCO. The following is
recommended;
Where boreholes are accessible it is recommended that NCO tries to resurvey boreholes
where this information is missing.
Downhole resistivity survey may be useful for verifying the position of the mineralization in
holes which do not have preserved core.
Depending on the outcome of the above and the core logging it may be necessary to twin
some of the boreholes to verify the geology if there are large areas where borehole data is
uncertain.
The Goldfields exploration program left many planned boreholes undrilled. These boreholes
are on the established grid and were meant to target down plunge extensions of the Central
Shoot. It is recommended that NCO continue with the same plan.
FillingapsinthecurrentdrillinggridonboththeCentralandEast/OstShoot.
The recommend grid as per the Goldfields programme is to test new areas at 400m section
spacings but with 100m spacings along a section to define the shoots lateral edges.
Once the shoot boundaries are defined infill drilling is proposed at 100m sections by 50m
spacing along section or at 50m x 50m if necessary in the shallower parts of the deposit.
The shallower parts of the deposit have been drilled. Chasing the extensions to the
mineralization will require boreholes in excess of 500m. While this is a good longer term goal
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it is recommended that NCO put the majority of their work programme in the first year
towards the evaluation of the currently defined mineral resource.
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18 REFERENCES
Ferneyhough, A.B. 1989. Surface EMP results for loops 13 to 28 over the Hoffnung and Otjituezu
Prospecting Grants, Gold Fields Namibia Limited internal Report.
Breitkopf, J.H. and Maiden K.J. (1988) Tectonic Setting of the Matchless Belt Pyritic Copper Deposits,
Namibia: Econ.Geol.,v.83, p. 710-723
Cox and Singer (1986) Mineral Deposit Models version 1 USGS Bull. 1693
(http://pubs.usgs.gov/bul/b1693/ )
Goldberg I., 1976. A preliminary account of the Otjihase copper deposit, South West Africa:
Econ.Geol.,v.71, p. 384-390.
Killick, A.M., 1983. Sulphide mineralization at Gorob and its genetic relationship to the Matchless
Member, Damara sequence, SWA/Namibia: Geol. Soc. South Africa Spec. Pub., v. 11, p. 381- 384.
Kotze, W,H, 2008. Independent Geologist’s Report On the Ongombo Base Metal Project (Epl3238) For
Ongombo Copper Limited, Geomine Consulting Namibia CC, 13 February 2008.
Maneschijn, G.D, 1991. The Ongombo semi-massive sulphide deposit, with special reference to diamond
drilling results. Internal Goldfields Namibia Limited report.
Marlow A. G., 2007. Technical Review of the Ongombo Copper Deposit in Namibia. Prepared for Avanti
Resources Pty Ltd. 54pp.
Moroni M., 1990. The Geology, Petrology and Geochemistry of the Mineralisation and Hydrothermal
Alteration at Ongeama, Ongombo and Matchless West Extension, Namibia. M.Sc. thesis Rhodes
University, 133pp.
Petzel. V.F.W, 1994. Drilling Proposal for the Ongombo Prospect for 1994. Goldfields Namibia Limited
Internal report pp3
Petzel, V.F.W. 1994b. Progress report for the Hoffnung Grant M46/3/1623 for the period June 1992 to
May 1994. Gold Fields Namibia internal report. 18pp.
Schneeweis, R. 1986. Progress Report for the Period March 1983 to May 1986, Hoffnung Prospecting
Grant M46/3/1623. Tsumeb Corporation Limited, Internal Report
Schneider G.I.C and Seeger K.G., (1992). Copper: Mineral Resources Series. Open File report MRS 49
Geological Survey of Namibia
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Weatherly 2011, Investor Presentation July 2011.
http://www.weatherlyplc.com/downloads/pdf/Weatherly_Presentation_July_2011.pdf
Used for geological modelling and data but not directly quoted ion the report
Corbett, D.H., 1990. Progress Report to the Mining Commissioner in Support of the Renewal of the
Hoffnung Prospecting Grant M46/3/1623 for a Further Period of Two Years from 10 September 1990.
Gold Fields Namibia Limited Report dated June 1990.
Kruger, T.L. 1993. Ongombo Prospect: Ost and Central Shoot Exploration Proposal. Gold Fields Namibia
Limited internal report for EC SYSMIN Report dated 20/40/1993. 9pp
Lubbe, B.L. 1994. Surface EM results for loops 29 to 34 over the Hoffnung Prospecting Grant
M46/3/1623. Gold Fields Namibia internal report, 3pp.
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APPENDIX A - DATA REVIEW HISTORICAL DRILLING
1 DRILLING METHODS
A combination of percussion (Schramm hammer drill) and diamond core drilling was used. Percussion
drilling of non-mineralized overburden with diamond tail was a common method used by Goldfields. Most
boreholes have one non-directional deflection. Core recovered was either “B” or “N” sized. Recoveries
were not recorded but drilling the recent site visit by Coffey mining, some of the historical holes
2 SURVEYING
2.1 Grid Control
Boreholes were laid out on a grid of sections 200m apart and 50-200m spacing along sections
(Figure 12.2_1). Drillling does not appear to have been systematic but dependant on yearly
budgets and targets. Some boreholes laid out and numbered were never drilled.
2.2 Borehole Collars
Electronic (scanned) copies of the original hand written datasheets and/or original prints from an
electronic database were provided to Coffey Mining. Borehole collars were surveyed by a
qualified surveyor and reported relative to an established baseline and in the local Namibian
coordinate system. This was then based on the LO (Gauss Conformal) Bessel 1841 (Schwarzeck
Datum) projection with the German legal metre (http://www.mme.gov.na/gsn/nam-map-
system.htm). Survey records are available for most boreholes and these coordinates are used in
the evaluation. Where records are not available, coordinates are estimated from old maps and
elevations estimated from a Google EarthTM
image. During the Site visit by Coffey Mining, no
borehole collars could be located due to thick grass. However, during 2007 and site visit by
Geomine (Kotze, 2008) found the old boreholes could be located but only boreholes from
OGB070 onwards were marked with a cement capping and metal plate with the borehole number.
Older boreholes had no identifying numbers.
2.3 Downhole Surveying
Electronic (scanned) copies of the original hand written datasheets and/or original prints from an
electronic database were provided to Coffey Mining. Downhole surveying was carried out by the
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drilling contractor. The actual instruments used at the time are not recorded however both single
shot and multishot cameras were available at the time.
It appears that both instruments were used as some boreholes have few widely spaced readings
typical for a single shot instrument and some have more regularly spaced and more frequent
readings typical of the multishot tools at the time.
It is believed that all for the boreholes were originally surveyed however not all of this data is now
available. In most cases the mother hole was surveyed but not the deflections. In some cases it
appears that the deflection was surveyed but not the mother hole. Some boreholes have both the
mother hole and deflection surveyed.
Boreholes have a very regular and predictable deviation caused by strong structural fabrics.
Where survey data was not available for a specific borehole, the survey data from the nearest
hole was used to predict the position of the mineralization. Deflections which were not surveyed
had the inclination increased by one degree in the direction of the borehole deviation which is
typical of a non-direction wedge at the time.
2.4 Surface Topography
The entire mineralized body is below surface and underground mining is the norm in this area. A
detailed topographic survey has not been carried out. Topography, where needed, can be
modelled from borehole collars and existing topographic data.
3 LOGGING, SAMPLING, ASSAYING AND DATA MANAGEMENT PROCEDURES
3.1 Geological Logging Electronic (scanned) copies of the original hand written datasheets
and/or original prints from an electronic database were provided to Coffey Mining. Detailed
logging by rocktype and mineralization was undertaken for all boreholes within the mineralized
zones. Logging and sampling information collected by Goldfields appears to have been stored in
an electronic database. Details of which are not known.
3.2 Sampling Diamond Core Samples Mineralized zones were sampled by taking half core.
Samples were taken as to honour geological boundaries. Samples were cut with a diamond saw.
3.3 Sample Preparation No details of the sample preparation are available. However,
Ongombo was a part of a larger copper mining operation and standard procedures of TCL and
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Goldfields, appropriate for the deposit at the time, would have been used.
3.4 Assaying No details on the assay methods are available. Normal procedures would have
been an acid digest followed by AAS finish for Copper and Zinc, Fire Assay for silver and gold.
3.5 Bulk Densities Bulk densities were routinely taken. One density measurement per assayed
sample was the norm. Details on the measurement procedures are not available.
3.6 Analytical Quality Control (QA/QC) Procedures and Data Analytical quality control was
not routinely the responsibility of the exploration staff and assays were done in-house at
TCL/Goldfields laboratories. No record of the laboratory quality control procedures is available to
Coffey Mining.
3.7 Data Verification Full data verification has not been completed by NCO or Coffey Mining.
Access to the drill core is needed to check the accuracy of the logging and to resample the
mineralized zones.
3.8 Core Storage. Borehole core that is available is stored at the Geological Survey of Namibia
storage facilities. When inspected the core boxes and core were found to be in good condition
with few signs of oxidation of the sulphides. Boxes were well marked and stored in a well
maintained facility. All depth and sample markings were still visible. Core is in a condition to make
re-logging and re- sampling possible.
4 SUMMARY
Data records for the Ongombo project are incomplete but sufficient information exists to evaluate the
potential of the project area.
Recommended