Cardinal Resources Limited: 4 Million Ounce Maiden Resource at Namdini
(firmenpresse) -
4 MILLION OUNCE MAIDEN RESOURCE AT NAMDINI
Cardinal Resources Limited (ASX: CDV) (Cardinal or the Company) is pleased to announce the maiden resource estimate for Namdini and results of the Phase 1, single hole, metallurgical testwork programme.
Highlights
- Maiden JORC Resource of circa 4 Million ounces gold
- Significant scope remains to expand the Resource with further drilling. The deposit remains open at depth and along strike
- 4 diamond rigs drilling on site operating 24/7, with a focus on both increasing the drill density of the maiden resource, plus extensional drilling to grow the resource
- Preliminary metallurgical test work completed, with further test work continuing to determine an optimal process route.
Commenting on the resource, Cardinal Resources Managing Director Archie Koimtsidis:
The Namdini maiden resource and the initial metallurgical results represent a major milestone for Cardinal and highlights the outstanding potential of the Namdini deposit, which remains open at depth and along strike.
With the first 4Moz now defined our aggressive drilling efforts will continue, with exploration around the existing resource already underway. Furthermore, we have four drill rigs onsite operating 24/7 to increase the size and confidence within the current resource.
Namdini is well located for future development and the project receives strong government and local landowner support.
RESOURCE ESTIMATE
Table 1 summarises the Mineral Resources at Namdini.
Table 1*
Namdini Gold Deposit
Grade-Tonnage Report - Multiple Indicator Kriging
with a Change Support
Selective Mining Unit (5mE by 10mN by 5mRL)
Classified in accordance with JORC 2012*
Lower cut offMillion TonneAverage GradeMillion
grade s (Au g/t) ounces
(g/t) (mt) (Au moz)
Indicated + Inferred Resources
0.3 123.0 1.1 4.2
0.4 110.0 1.2 4.1
0.5 96.1 1.3 3.9
0.6 82.3 1.4 3.6
Indicated Resources
0.3 8.28 1.00 0.27
0.4 7.20 1.10 0.25
0.5 6.22 1.20 0.24
0.6 5.35 1.30 0.22
Inferred Resources
0.3 114.7 1.1 3.9
0.4 102.8 1.2 3.8
0.5 89.9 1.3 3.6
0.6 77.0 1.4 3.4
* Mineral resources are not ore reserves and do not have demonstrated economic viability. All figures in Table 1 have been rounded to reflect the relative accuracy of the estimates. For the assessment of reasonable prospects of economic extraction, mineral resources have been assessed using Lerchs-Grossman pit optimisation, based on a gold price of US$1,550/oz, and the following key input parameters: mill-flotation-concentrate regrind-CIL process route with metallurgical recovery of 0% for oxidized mineralisation (estimate only), 50% for transitional mineralisation (estimate only), 75% for fresh mineralisation; assuming a bulk mining, low to moderate mining selectivity open pit operation with operating costs appropriate for West Africa. Depending on key parameters such as gold price, annual throughput, process plant recoveries and operating costs, cut off grades are likely to be in the range 0.3g/t to 0.6g/t.
The internal pit optimisation has demonstrated that the reported resource has reasonable prospects for economic extraction.
Figure 1 shows a perspective view of the 0.4g/t block model grade shell and the reasonable prospects of economic extraction pit optimisation pit shell. Figure 2 (Section L) and Figure 3 (Section N) display representative cross sections through the MIK block model, along with 10 metre drill hole composites of the gold assay data, while Figure 4 displays a long section, looking East, through the MIK block model. The figures show the reasonable prospects of economic extraction pit shell.
Figures 2 to 4 indicate that the deposit is open at depth and along strike. As a result, a multi-rig drill programme has been developed and initiated to carry out extension drilling, both up dip, down dip and to the North and South of the currently defined deposit. Further details of the planned programme will be included in a forthcoming release to the ASX.
Colour coding in Figures 2 to 4 is based on gold grade as follows:
- Less than 0.3g/t: Grey (for drill holes), not displayed for the MIK block model.
- 0.3g/t to 0.6g/t: Blue
- 0.6g/t to 0.8g/t: Green
- 0.8g/t to 1.0g/t: Orange
- 1.0g/t to 2.0g/t: Red
- Greater than 2.0g/t: Magenta
Figure 5 displays a long section, looking East, with the JORC resource categories.
Figure 6 shows the MIK block model with blocks returning 0.4g/t Au or higher colour-coded red along with the reasonable prospects of economic extraction pit shell and displays a cross section (Section I), a level plan (120mRL) and a long section looking east. The wide zones of continuous gold mineralisation above a cut off grade of 0.4g/t Au are clearly evident.
Table 2 summarises the percentage proportion of tonnes and contained gold, subdivided by lithology. It is evident that the gold mineralisation within the currently defined Namdini deposit is dominated by metavolcanics, followed by granite and then diorite.
Table 2
Namdini Deposit
Grade-Tonnage Report - Multiple Indicator Kriging with a
Change
Support
Selective Mining Unit (5mE by 10mN by 5mRL)
Mineralised lithology proportions of tonnes and
contained
gold
Cut off gTonnes Contained Gold
rade
(g/t Au)
MetavolcanGranitDioritMetavolcanGraniteDiorite
ics e e ics
0.3 57% 30% 13% 60% 28% 12%
0.4 57% 31% 12% 61% 28% 12%
0.5 57% 30% 12% 61% 27% 11%
0,6 58% 30% 12% 61% 27% 11%
* Note percentages may not total 100% due to rounding (metasediments less than 1%)
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Figure 1: Perspective view of the 0.4g/t Au grade shell
View Towards Northeast
400m scale bar
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Figure 2: Typical cross section (Section L) through the
MIK
resour
ce model and 10m drill composites: Au g/t
100m scale bar
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Figure 3: Typical cross section (Section N) through the
MIK resource model and 10m drill composites: Au
g/t
100m scale bar
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Figure 4: Long section (looking east) through the MIK
resource model and 10m
drill
composites: Au g/t
200m scale bar
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Figure 5: Long section (looking east) with JORC resource
categories
(Indicated Resource: Red, Inferred Resource: Blue)
Scale Bar: 200m
The following information summarises key parameters relating to the resource estimation (the Orefind structural and geological modelling study report and the EGRM Pty Ltd resource estimation report will be available on the Cardinal Resources website):
- Geological and structural modelling: Logging, interpretation and modelling were undertaken by Cardinal Resources technical staff and specialist consultants Orefind Pty Ltd, resulting in a three-dimensional model of key lithologies and weathering zones.
- Survey Control: A detailed topographic survey was completed. Drill hole collars were surveyed using differential GPS (DGPS), with down hole surveys taken at 30m intervals using electronic multi-shot equipment.
- Bulk density data: Bulk densities are routinely measured as part of the exploration data acquisition protocols. The bulk density database for resource estimate comprised 1,395 measurements. Statistical analysis was undertaken on the bulk density data and a matrix of bulk densities were applied based on lithology and weathering zone. The great majority of the Namdini deposit is fresh bedrock. Bulk densities vary from 1.80 tonnes per cubic metre (t/cm) for strongly weathered rock to 2.73 t/cm (for Granite) and 2.82-2.83 t/cm (for metavolcanics, diorite and metasediments).
- Grade Estimation: Following detailed statistical and geostatistical analysis, including the application of 15g/t upper cut to 3m down hole composites, grade estimation was undertaken using MIK with a change of support to produce a selective mining model. Block model development is based on a parent block size of 20mE by 50mN by 10mRL, with sub-celling to the selective mining unit (SMU) block size of 5mE by 10mN by 5mRL. The majority of categorised blocks were estimated in three passes. In addition, blocks in excess of 75m from data were excluded from resource reporting. Validation of the MIK model was undertaken visually and statistically.
- Conditional Simulation Study: A conditional simulation study was undertaken on the area of close-spaced drilling at the southern end of the Namdini deposit for both grade estimation validation purposes and for additional SMU selectivity sensitivity studies.
- Resource Classification and Mineral Resource Reporting: The Namdini resource has been classified in accordance with the guidelines set out in the 2012 Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC Code). The assessment of confidence levels of the key categorization criteria including the confidence of the resource development data, the geological interpretation, the drilling density and grade estimation confidence has been undertaken and is summarised in Appendix 1.
Based on the assessment of the key criteria and using a 0.2g/t indicator cut off boundary for reporting purposes, the Namdini deposit has been categorised as a combination of Indicated and Inferred Resources, as summarised in Table 1. In summary, blocks estimated based on an approximate 20mE by 20mN drill spacing have been classified as an Indicated Resource. Those blocks not classified as an Indicated Resource but estimated with acceptable confidence and within 75m of drilling data are considered an Inferred Resource.
The resource estimation report from EGRM Consulting (Perth, Australia) will be lodged on the Cardinal Resources website in due course.
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7 Nov 2016 4 Million Ounce Maiden Resource at Namdinprcom.
007
7 Nov 2016 4 Million Ounce Maiden Resource at Namdinprcom.
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Figure 6: Cross Section (Line I), Plan (120mRL) and Long
Section (Looking
East)
/>0.4g/t Au cut off blocks highlighted. Scale Bars: 100m,
200m & 200m
respectively
METALLURGICAL TESTWORK SUMMARY
Suntech Geomet Laboratories (Suntech), based in Johannesburg, South Africa have been contracted to carry out a range of metallurgical testwork on a 332 kilogram composite sample of quarter HQ diamond drill core obtained from drill hole NMDD005 (original hole code NMDD422-736), which includes carefully weighted proportions of metavolcanics, granite and diorite. The individual components were used to make a master composite (MC) which grades 1.42g/t and 1.1% sulphur. Figure 7 shows the location of hole NMDD005 relative to the current Namdini drilling.
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Figure 7: Location of NMDD005 (red) relative to the
current
Namdini drilling
Scale bar: 100m
Scope of the metallurgical testwork
The main aims of the testwork programme were as follows:
- To characterize the occurrence, and confirm the association, of the gold mineralisation
- The amenability of gold recovery to a range of extraction methods on both the run of mine (ROM) mineralisation and flotation concentrate.
- To confirm the process route best suited to treating the constituent ores types present - whole ore leaching, or pre-concentration with subsequent leaching on a smaller weight of concentrate
- To determine the acceptable coarsest grind for optimal recovery of gold for the pre-concentration flowsheet, to determine the best reagent suite for optimal recovery and upgrading of gold into a concentrate suitable for further processing.
- To determine the mineralogical characteristics of the gold mineralisation and concentrate associations using QEMSCAN (quantitative electron microscopy) and diagnostic leach evaluation.
The metallurgical report from Suntech Geomet Laboratories (South Africa) will be available on the Cardinal Resources website.
Metallurgical testwork results
Key metallurgical testwork results are summarised below:
- Comminution Testwork: The Bond Ball Work Index (BBWI) for the MC is 14.9 kWh/t. SAG Power Index (SPI) tests were carried out on the individual lithologies and the MC. The SPI tests can be used to predict throughputs for SAG/AG mills and in the determination of power requirements. SPI values of 8.83 to 9.57 kWh/t indicate moderate comminution characteristics.
- Mineralogical Characterisation: Mineralogical characterisation of the MC and sulphide concentrate used polished sections. The bulk of the gold grains in the MC and the sulphide concentrate are fine grained (88.7% of the gold grains in the MC less than 9.6 microns and 68.3% in the sulphide concentrate). In the sulphide concentrate, gold is dominantly associated with pyrite.
- Diagnostics Leach Tests: Diagnostic leach tests were carried out on the MC and a final flotation concentrate. Table 3 summarises the results of the diagnostic leach tests.
Table 3
Diagnostic leach tests
Test Au association/Solubilisation proPercentage
cess Recovery
Master Flotation
Composi Concentra
te te
1 Free milling (CIP - no carbon) 61.3 66.7
2 Total free milling + preg-robbed 64.1 67.8
Au
(CIL)
3 Au extracted by mild oxidized 8.0 3.0
pre-leach (Au associated with
pyrrhotite, calcite, dolomite
and
hematite)
4 Au extracted by severe oxidative 27.3 19.0
pre-leach (Au associated with
pyrite, arsenopyrite etc)
5 Au extracted by complete 0.0 1.4
oxidation (Au associated with
kerogen)
6 Undissolved gold (Au assumed to 0.6 8.7
be associated with
quartz)
Total 100.0 100.0
- Grind optimisation: Grind optimisation tests on the MC indicated that a p80 -75 microns is the optimum grind size.
- Whole rock - individual variability cyanidation tests: Variability cyanidation tests (24/48 hour tests on notional p80 -75 microns material) on the individual lithologies indicated that the diorites returned the highest recovery (p87.5% - 75 microns, recovery 70.4%) followed by the metavolcanics (p89.1% -75 microns, recovery 63.8%) and the granites (p66.3% -75 microns, 49,1%). It is noted that the size reduction based on the MC milling calibration tests, resulted in the granite undergoing less particle size reduction compared to the metavolcanics and diorite, which could explain the lower gold recovery in the granite compared to the other two lithologies. Further testwork is planned.
- Flotation Testwork:
o Reagent scouting tests: 15 reagent scouting tests (at a p80 -75 microns) indicated that the optimum reagent combination produced a cleaner concentrate with a mass pull of 2.2% of the original mass, a gold grade of 53.6g/t and 89.2% gold recovery. Rougher gold recoveries above 90% were achieved in 12 out of 15 of the scouting tests, with 9 returning 92% to 96%.
o Flotation rate test: A flotation rate test on the MC exhibited fast flotation characteristics with very efficient mass pulls, with approximately 82% of the total Au recovered into a 3.2% mass within the first 3 minutes of flotation. All three lithologies exhibited good flotation response.
o Variability flotation tests: All three lithologies exhibited good flotation responses with 83.5% Au/95% S, 81.7% Au/93.8% S and 90.4% Au/98.9% S of the gold and sulphur recovered into the flotation concentrate, from the volcaniclastics, granite and diorite respectively.
o Grind optimisation flotation tests: Flotation tests were carried out for 5 grind sizes (212 to 53 microns). Best recoveries (to cleaner concentrate) were obtained for p80 -75 microns (89.2% Au recovery for 53.6g/t flotation concentrate grade).
o Gold dissolution tests on flotation products: CIL tests on the grind optimisation tests rougher tails show that a p80 of -75 microns returned the highest recovery.
o Cyanidation of concentrate after ultra-fine milling: Ultra-fine milling (UFG) produced significant improvements in overall recovery compared to the gold recoveries from the flotation concentrate as received (p80 -109 microns, 68% Au recovery). At a p80 of -22 microns the gold recovery improved to 77.9% whilst at a p80 of -15 microns the gold recovery was 80.2%. As such, overall concentrate recoveries of approximately 80% have been produced from cyanide leaching UFG concentrates. Further tests will be undertaken with the addition of leach accelerants to optimize conditions.
Current potential metallurgical flowsheet
Based on the metallurgical testwork carried out to date, along with generic capital and operating cost ranking of the flowsheets considered, and acknowledging that it is taken from only one drill hole within the one kilometer long Namdini deposit, with an aim to produce gold dore on site, the pre-concentration and concentrate leach process flowsheet shows good potential (mill-flotation-concentrate regrind-CIL) with overall gold recoveries of 75% to 76%.
Other options that will be considered include roasting of sulphides (which has achieved 86% to 87% gold recovery from concentrates) or the biological degradation of sulphides (BIOX), which is targeted to produce higher recoveries than roasting, or the production of a high sulphur, gold-rich concentrate for transport and sale to smelters.
Significant additional metallurgical testwork is planned.
Future metallurgical testwork
An additional metallurgical scan sampling and analytical programme is currently underway, based on the production of notional 10m down hole composites using quarter HQ core sample coarse reject material. Approximately 940 ten metre 2.5kg composites, representing approximately 9.4km of diamond drilling (with an estimated total mass of 2,350 kg) are being produced using a composite cut off grade of 0.1g/t Au. The composites will used as the sample source for the following analyses:
- 2kg 24-hour cyanidation bottle roll with duplicate 50gm fire assays on the washed leach reside material.
- LECO furnace analyses of total sulphur and total carbon.
- Inductively couple plasma (ICP) analysis of 49 elements using the ICP-OES and ICP-MS techniques.
The aim of the programme is to produce a three-dimensional multi-element model of the Namdini deposit, along with initial cyanidation leach characteristics, sulphur and carbon contents in order to guide the next phase of metallurgical testwork, which will begin immediately on receipt of the scan sampling programme results.
Competent Persons Statement
Information in this release, which relates to the resource estimation of the Namdini deposit is based on the work of Brett Gossage, MAusIMM, who has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and the activities being reported upon to qualify as a Competent Person, as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Mr Gossage consents to the inclusion in this report of the statements based on the information in the form and context in which it appears
Information in this release that relates to the Namdini Project is based on the results of the Metallurgical Testwork program undertaken at SunTech Laboratories, Johannesburg, South Africa. The work has been monitored on behalf of Cardinal Resources by Simon Meik, FAusIMM CP (No. 106146), who has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and the activities being reported upon to qualify as a Competent Person, as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Dr Meik consents to the inclusion in this report of the statements based on the information in the form and context in which it appears
The overall release has been compiled and the reasonable prospects of economic extraction pit optimisation, has been carried out by Dr Julian F. H. Barnes, FAusIMM, MAIG, Technical Manager of Cardinal Resources, who has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and the activities being reported upon to qualify as a Competent Person, as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Dr Barnes consents to the inclusion in this report of the statements based on the information in the form and context in which it appears.
For further information contact:
Archie Koimtsidis
Managing Director
Cardinal Resources Limited
P: +233 (0)26 190 5220
Skype: cardinal.archie
Disclaimer
This ASX announcement (Announcement) has been prepared by Cardinal Resources Limited (ABN: 56 147 325 620) (Cardinal or the Company).
This Announcement contains summary information about Cardinal, its subsidiaries and their activities, which is current as at the date of this Announcement. The information in this Announcement is of a general nature and does not purport to be complete nor does it contain all the information, which a prospective investor may require in evaluating a possible investment in Cardinal.
By its very nature exploration for minerals is a high-risk business and is not suitable for certain investors. Cardinals securities are speculative. Potential investors should consult their stockbroker or financial advisor. There are a number of risks, both specific to Cardinal and of a general nature which may affect the future operating and financial performance of Cardinal and the value of an investment in Cardinal including but not limited to economic conditions, stock market fluctuations, gold provide movements, regional infrastructure constraints, timing of approvals from relevant authorities, regulatory risks, operational risks and reliance on key personnel and foreign currency fluctuations.
Except for statutory liability which cannot be excluded, each of Cardinals, its officers, employees and advisors expressly disclaim any responsibility for the accuracy or completeness of the material contained in this Announcement and excludes all liability whatsoever (including in negligence) for any loss or damage which may be suffered by any person as a consequence of any information in this Announcement or any error or omission here from. The Company is under no obligation to update any person regarding any inaccuracy, omission or change in information in this Announcement or any other information made available to a person nor any obligation to furnish the person with any further information. Recipients of this Announcement should make their own independent assessment and determination as to the Companys prospects, its business, assets and liabilities as well as the matters covered in this Announcement.
Not an offer
This Announcement is for information purposes only and does not constitute or form any part of any offer or invitation to sell or issue, or any solicitation of any offer to purchase or subscribe for, any securities in the Company in any jurisdiction. It is not intended to be and is not a prospectus, product disclosure statement, offering memorandum or private placement memorandum for the purpose of Chapter 6D of the Corporation Act 2001. This Announcement and its contents must not be distributed, transmitted or viewed by any person in any jurisdiction where the distribution, transmission or viewing of this Announcement would be unlawful under the securities or other laws of that or any other jurisdiction. This Announcement is not considered a recommendation by the Company or any of its affiliates, directors or officers that any recipient invest in the Company nor does it constitute as any investment, accounting financial, legal or tax advice.
Not financial product advice
This Announcement does not contain all information which may be material to the making of a decision in relation to the Company. Recipients of this document should carefully consider whether the securities issued by the Company are an appropriate investment for them in light of their personal circumstances, including their financial and taxation position. No account has been taken of the objectives, financial situation or needs of any recipient of this document. Any investor should seek independent financial and taxation advice independent assessment and determination as to the Companys prospects prior to making any investment decision, and should not rely on the information in this Announcement for that purpose. Neither the Company nor its related bodies corporate is licensed to provide financial advice in respect of the Companys securities or any financial products. This Announcement does not involve or imply a recommendation or a statement of opinion in respect of whether to buy, sell or hold securities in the Company. The securities issued by the Company are considered speculative and there is no guarantee that they will make a return on the capital invested, that dividends will be paid on the shares or that there will be an increase in the value of the shares in the future.
Forward-looking statements
Certain statements contained in this Announcement, including information as to the future financial or operating performance of Cardinal and its projects, may also include statements which are forwardlooking statements that may include, among other things, statements regarding targets, estimates and assumptions in respect of mineral reserves and mineral resources and anticipated grades and recovery rates, production and prices, recovery costs and results, capital expenditures, and are or may be based on assumptions and estimates related to future technical, economic, market, political, social and other conditions. These forward - looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable by Cardinal, are inherently subject to significant technical, business, economic, competitive political and social uncertainties and contingencies, and involve known and unknown risks and uncertainties that could cause actual events or results to differ materially from estimated or anticipated events or results reflected in such forwardlooking statements.
Cardinal disclaims any intent or obligation to update publicly or release any revisions to any forwardlooking statements, whether as a result of new information, future events, circumstances or results or otherwise after todays date or to reflect the occurrence of unanticipated events, other than required by the Corporations Act and ASX Listing Rules. The words believe, expect, anticipate, indicate, contemplate, target, plan, intends, continue, budget, estimate, may, will, schedule and similar expressions identify forwardlooking statements.
All forward-looking statements made in this Announcement are qualified by the foregoing cautionary statements. Investors are cautioned that forwardlooking statements are not guarantees of future performance and accordingly investors are cautioned not to put undue reliance on forwardlooking statements due to the inherent uncertainty therein.
No verification
Although all reasonable care has been undertaken to ensure that the facts and opinions given in this Announcement are accurate, the information provided in this Announcement (including information derived from publicly available sources) may not been independently verified.
APPENDIX 1
JORC Code, 2012 Edition - Table 1 report template
Please refer to Cardinal Resources Press Release 16 August 2016 for full details of Section 1 (Sampling Techniques and Data).
Section 3 Estimation and Reporting of Mineral Resources
(Criteria listed in section 1, and where relevant in section 2, also apply to this section.)
Criteria JORC Code explanation Commentary
Database Integrity Measures taken to ensure that All geological and field data
data has not been corrupted is entered
by, for example,
transcription or keying using data-loggers and
errors, between its initial software developed by
collection and its use for Maxwell
Mineral Resource estimation
purposes. GeoServices, that includes loo
kup tables and fixed
formatting (and protected
from modification) thus only
allowing data to be entered
using the Cardinal
geological code system and
sample protocol. Data is
then loaded to the
Datashed database, which was
managed by consultants
Maxwell
GeoServices with access on
site for the Cardinal
database
personnel. Caedinal technical
personnel validated the
database using
Micromine software.
The Datashed database is then
reviewed against the
original logging
spreadsheets and the assay
data checked against the
supplied assay
certificates.
Data validation procedures Following importation the
used. data goes through a series
of digital checks for
duplication and
non-conformity, followed by
manual validation by the
relevant project geologist
who manually checks the
collar, survey, assay and
geology for errors against
the original field data and
final paper copies of the
assays. The process is
documented, including the
recording of holes checked,
errors found, corrections
made and the date of
database
update.
Site visits Comment on any site visits Brett Gossage, Principal for
undertaken by the Competent EGRM Consulting Pty Ltd,
Person and the outcome of completed a site visit in
those July 2016 to review the
visits. exploration procedures.
Limited drilling was being
completed but appeared to be
completed in an appropriate
manner. Sampling protocols
observed were considered to
meet high industry
standards.
The site visit included the
reviewing of geological
logging and supervising
independent check assaying.
The check assaying
confirmed the location and
tenor of the assaying
contained within the
database. The geological
logging was found to be
consistent and no material
issues noted. The
drillhole collar survey could
be
confirmed by check handheld
GPS survey with the
drillhole collars well
maintained.
In addition to the site visit
observations, the majority
of assay data (>90%) were
checked against the original
laboratory supplied assay
certificates.
If no site visits have been Not applicable.
undertaken indicate why this
is the
case.
Geological interpretation Confidence in (or conversely, The confidence in the
the uncertainty of) the geological interpretation is
geological interpretation of high although infill
the mineral drilling is required and
deposit. additional geological work
is required to improve the
model locally once
additional data is acquired.
A model of the lithology and
weathering was generated
prior to the mineralisation
domain interpretation
commencing. This work was
completed based a programme
of logging and mapping, and
structural interpretation by
independent geological
consultants
OreFind.
Mineralisation at the Namdini
project area is developed in
both the
meta-volcano-sedimentary
rocks and
tonalite. The tonalite has
been extensively mined by
artisanal miners, with
lesser amount
of
artisanal activity in the
volcano-sedimentary units.
In all rock types the
mineralisation is
accompanied by visible
disseminated sulphides of
pyrite and
arsenopyrite in both the
veins and wall rocks. In
diamond core the mineralized
zones are visually
distinctive due to the
presence of mm- to cm-width
quartz-carbonate veins that
are commonly folded and that
possess yellow-brown
sericite-carbonate
selvedges. Gold as primarily
associated with sulphides,
in particular pyrite where
it commonly occurs as
inclusions and on the
crystal margins. Gold was
also noted in
phyllite matrix and, to a
much lesser extent, in
association with ilmenite.
While visible gold is rare,
identified examples occurred
in strongly altered granite
and were associated with
silica-sericite shears that
had sub-mm widths.
Based on these observations,
and geological
interpretations, a broad
(0.1gt Au) low grade
mineralisation package was
developed. The
mineralisation constraint
was traceable at low grades
for overall 1000m and is up
to 300m wide. The
mineralisation dips
approximately 55° to 60°
towards the
west
.
Nature of the data used and The geological data used to
of any assumptions construct the geological
made. model includes regional and
surface mapping and logging
of RC and diamond core
drilling. A nominal 0.1g/t
Au lower cut-off grade was
applied to the
mineralisation model.
The effect, if any, of The geology of the deposit is
alternative interpretations relatively simple, and the
on Mineral Resource interpretation is considered
estimation. robust. There is no
apparent alternative to the
interpretation in the
companys opinion at this
point.
The use of geology in guiding The mineralisation geometry
and controlling Mineral has a strong relationship
Resource with the interpreted
estimation. alteration and structure.
The lithology contacts and
the weathering changes do
not appear to materially
control the mineralisation
although the metavolcanics
and the
tonalite (granite)
mineralisation
is on average higher grade
than the diorite and
metasediment mineralisation.
Little grade variation is
noted between the different
weathering groupings. The
grade estimate is based on a
gold grades and the
mineralisation package
defined above a 0.1gt Au
lower
cutoff grade.
The factors affecting A broad zone of anomalous
continuity both of grade and mineralisation is
geology. interpreted. The grade
continuity at lower
cutoff grades is good, however
this grade continuity is
materially reduced at higher
cutoff grades.
Dimensions The extent and variability of The approximate dimensions of
the Mineral Resource the deposit are 1100m along
expressed as length (along strike (N-S), 300m across
strike or otherwise), plan (E-W), and 400m below
width, and depth below surface.
surface to the upper and is spread in a more
lower limits of the Mineral flat-lying manner in a
Resource. westerly
dir
Estimation and modeling techniThe nature and The resource estimate has
ques appropriateness of the been generated via Multiple
estimation technique(s) Indicator Kriging (MIK) with
applied and key assumptions, a change of support. The
including treatment of MIK estimation was
extreme grade values, constrained within the
0.1g/t Au mineralisation
domaining, interpolation zone interpretation. MIK is
parameters and maximum considered an appropriate
distance of extrapolation grade estimation method for
from data points. If a
computer assisted estimation Namdini given the high degree
method was chosen include a of spatial variability of
description of computer the gold assay data
software and parameters (relative to the data
used. spacing) present within the
mineralisation
zones.
The grade estimate is based
on 3m down-the-hole
composites of the resource
development drilling data at
Namdini. High grade cuts (as
described below) have been
applied to composites to
limit the influence of
higher grade data.
Detailed statistical and
geostatistical
investigations have been
completed on the captured
estimation data set. This
includes exploration data
analysis, boundary analysis,
variography, grade estimation
trials and change of support
studies. These
investigations have been
completed on a domain by
domain basis.
Grade estimation has been
completed in multiple
estimation passes with
expanding sample search
radii. A first higher
confidence estimate was
completed (Indicated
Resource where other
criteria were met) with
sample search radii of 50m x
50m x 30m and a sample
search oriented consistent
with the major controls
interpreted for each
estimation domain.
Subsequent estimation
passes (passes 2 and 3) was
generated with expanded
sample searches of 50%
increase in sample search
radii. A maximum of 32 and
with a minimum of 16 (passes
1 and 2) and 10 (pass 3)
composites have been used in
grade estimation. A maximum
number of 6 composites from
any
drillhole have been allowed
to estimate a single
block.
The grade estimation has been
generated using a
combination of mine planning
and specialist
geostatistical software
packages. Vulcan have been
used for geological
modelling and block model
construction and
Isatis for statistical and
geostatistical studies and
grade estimation.
The availability of check No check estimates are
estimates, previous available.
estimates and/or mine
production records and The estimate has been
whether the Mineral Resource generated in regions where
estimate takes appropriate artisanal mining has been
account of such
data. completed, however no records
of production are available.
The assumptions made No by-products are present or
regarding recovery of modelled.
by-products.
Estimation of deleterious No deleterious elements have
elements or other non-grade been estimated
variables of economic
significance (e.g. sulphur to date at Namdini. A
for acid mine drainage metallurgical scan sampling
characterisation). programme based on 10m
composites of coarse reject
material from HQ quarte core
is underway. The composites
will
be assayed for total sulphur
and carbon by LECO furnace,
and
49 elements by ICP-OES and
ICP-MS
and the data will be used to g
enerate
a geo-metallurgical model of
the
Namdini deposit.
The MIK estimate is based on
In the case of block model a block (panel) size of 20m
interpolation, the block (East) by 50m (North) by 10m
size in relation to the (Elevation), which considers
average sample spacing and the drilling density for the
the search vast majority of the
employed. deposit. From the MIK panel
estimate, a selective mining
unit (SMU) estimate has been
generated based on a 5m
(East) by 10m (North) and 5m
(Elevation) block size.
This SMU is based on the
envisaged mining practises
likely to be employed at
Namdini. The MIK SMU has
been localised to SMU size
blocks for visualisation and
mine planning
purposes.
Any assumptions behind A selective mining estimate
modelling of selective has been generated for the
mining MIK using a change of
units. support targeting a 5m
(East) by 10m (North) and 5m
(Elevation) SMU. The change
of support has been
completed using an indirect
lognormal correction. The
selective mining estimate
(MIK) has been compared to a
global change of support
analysis completed using a
discrete
gaussian change of support
model as part of the
validation
procedures.
Any assumptions about No correlated variables have
correlation between been investigated or
variables. estimated.
Description of how the The grade estimate is based
geological interpretation on a nominal 0.1g/t Au lower
was used to control the cut-off grade mineralisation
resource constraint. The
estimates. mineralisation constraint
was reviewed based on
lithological and weathering
interpretations generated
but were determined to not
control the distribution of
the gold mineralisation. The
lithology and weathering
constraints have been coded
to the block model but have
been used as soft boundaries
with composites searched
only based on the grade
constraint. Statistical
investigations have been
completed to test the change
in statistical and spatial
characteristics of the
domains grouped by
weathering. This has
included boundary analysis
to determine the
applicability of soft or
hard boundaries between the
Leseranfragen:
Datum: 07.11.2016 - 15:03 Uhr
Sprache: Deutsch
News-ID 505368
Anzahl Zeichen: 91841
contact information:
Town:
Wien
Kategorie:
Business News
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"
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