Criteria
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JORC Code
explanation
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Commentary
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Sampling
techniques
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- Nature and
quality of sampling (e.g. cut channels, random chips, or specific
specialised industry standard measurement tools appropriate to the
minerals under investigation, such as down hole gamma sondes, or
handheld XRF instruments, etc). These examples should not be taken
as limiting the broad meaning of sampling.
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- The assay data
reported herein is based on sampling of diamond drill core of PQ,
HQ and NQ diameter which was cut with a diamond core saw. Samples
are generally of 1 m length, although occasionally slightly longer
or shorter where changes in lithology, core size or core recovery
required adjustments; samples are not more than 2 m
length.
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- Include
reference to measures taken to ensure sample representivity and the
appropriate calibration of any measurement tools or systems
used.
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- The length of each drill run is recorded and
the recovery for each run calculated on site and checked again at
the core shed. Certified reference standards and blank samples were
submitted to assess the accuracy and precision of the results and
every 20th sample was sawn into two and the two quarter core
samples submitted for analysis separately as a duplicate
sample.
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- Aspects of the
determination of mineralisation that are Material to the Public
Report.
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- Half core samples were cut and sent for
analysis by an independent ISO-certified laboratory (Intertek
McPhar Laboratory) in Manila. Samples were crushed and pulverised
(95% <75 μm). Gold was analysed by 50 g fire assay and the other
elements including copper and iron by ICP-MS (Inductively Coupled
Plasma Mass Spectrometry) or ICP-OES (Inductively Coupled Plasma
Optical Emission Spectrometry) following a four-acid digest.
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Drilling
techniques
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- Drill type (e.g. core, reverse
circulation, open-hole hammer, rotary air blast, auger, Bangka,
sonic, etc) and details (eg core diameter, triple or standard tube,
depth of diamond tails, face-sampling bit or other type, whether
core is oriented and if so, by what method, etc).
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- Drilling was by PQ, HQ and NQ diameter, triple tube
diamond coring. The core was not orientated.
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Drill sample
recovery
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- Method of
recording and assessing core and chip sample recoveries and results
assessed.
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- Core recovery is initially measured on site by
trained technicians and by the supervising geologist. Any core loss
is measured, the percentage is calculated and both are recorded in
the geotechnical log for reference when assessing assay
results.
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- Measures taken to maximise sample recovery
and ensure representative nature of the samples.
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- All care is taken to ensure maximum recovery
of diamond core and drillers are informed of the importance of core
recovery. Any areas of poor core recovery are sampled separately
thus assay results can be directly related to core recovery.
The majority of
the mineralisation is in fresh rock where recoveries are greater
than 90%. Most mineralisation occurs in wide intersections of
massive magnetite skarn with relatively uniform copper and gold
grades. Core loss occurs in fracture zones but is usually not a
significant problem i.e. the core lost in fracture zones is
unlikely to have been significantly higher or lower grade than the
surrounding material. In the weathered hematitic oxidised zones
some core loss is unavoidable, but overall recovery is generally
>90% and the core loss is volumetrically minor in the
mineralised zones. In areas of poor recovery, the sample intervals
are arranged to coincide with drill runs, thus areas of different
core loss percentage are specific to individual samples which can
be assessed when interpreting analytical results and modelled in
future resource estimation studies. Where an area of 100% core loss
is identified the sample intervals are marked to each side of the
zone and the zone is designated "No core" and assigned zero value
in the various log sheets and geochemical
database.
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- Whether a relationship exists between
sample recovery and grade and whether sample bias may have occurred
due to preferential loss/gain of fine/coarse material.
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- There is no discernible relationship between
core recovery and grade. The skarn bodies are relatively uniform
over significant lengths and the copper and gold grades are not
related to clay and fracture zones which are the main causes of
core loss.
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Logging
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- Whether core and chip samples have been
geologically and geotechnically logged to a level of detail to
support appropriate Mineral Resource estimation, mining studies and
metallurgical studies.
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- Diamond drill core for each entire drill hole was
logged in significant detail in a number of logging sheets
including a geological log, a structural log, a geotechnical log
and a magnetic susceptibility log for the entire drill hole.
Mineralised and sampled intervals are logged individually in a
separate quantitative mineral log with percentages of the different
copper minerals being recorded. The logging is appropriate for
mineral resource estimates and mining studies.
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- Whether logging is qualitative or
quantitative in nature. Core (or costean, channel, etc.)
photography.
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- Most of the geological logging is a mixture
of qualitative (descriptions of the various geological features)
and quantitative (numbers and angles of veins and fracture zones,
mineral percentages etc.). The quantitative mineralisation log and
the magnetic susceptibility log are quantitative. Photographs are
taken of all core (both wet and dry) prior to the core being
cut.
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- The total length and percentage of the
relevant intersections logged.
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- All core, including barren overburden is
logged in the various logging sheets noted above apart from the
quantitative mineralisation log in which only the mineralised
intervals sent for geochemical analysis are logged in greater
detail.
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Sub-sampling
techniques and sample preparation
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- If core, whether
cut or sawn and whether quarter, half or all core
taken.
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- All sampling data
is from diamond drill core. Samples are of sawn half core except
for duplicate samples which are quarter core. Half core is bagged
and sent to an ISO-certified independent laboratory for analysis.
The other half retained for reference and/or further
testwork.
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- If non-core, whether riffled, tube
sampled, rotary split, etc and whether sampled wet or dry.
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- Not applicable for diamond core
drilling.
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- For all sample types, the nature, quality
and appropriateness of the sample preparation technique.
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- All core samples were dried, crushed to
95% <10 mm and a 1.5 kg sub-sample is separated using a riffle
splitter and pulverised to 95% <75 μm. A 50 g sub-sample
is utilised as a fire-assay charge for gold analysis. The
sample preparation technique and sub-sampling is appropriate for
the mineralisation.
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- Quality control procedures adopted for all
sub-sampling stages to maximise representivity of samples.
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- Blank samples and duplicate samples are
submitted routinely to monitor the sampling and analytical process
and to ensure that samples are representative of in situ material.
One in every 20 samples of half core is sawn again to produce two
quarter core duplicate samples which are submitted to the
laboratory separately with different sample numbers. A blank sample
was inserted into sample batches at every 20th
sample.
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- Measures taken to ensure that the sampling
is representative of the in situ material collected, including for
instance results for field duplicate/second-half sampling.
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- The magnetite skarn mineralisation occurs in
extensive zones of magnetite skarn with disseminated chalcopyrite,
containing gold. The sample size of approximately 1 m core length
is suitable in respect to the grain size of the
mineralisation.
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- Whether sample sizes are appropriate to
the grain size of the material being sampled.
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- The sample size is considered appropriate for
the material sampled. It is believed that grain size has no bearing
on the grade of the sampled material.
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Quality of
assay data and laboratory tests
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- The nature, quality and appropriateness of the
assaying and laboratory procedures used and whether the technique
is considered partial or total.
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- All core samples were analysed at an ISO-certified
independent laboratory. Gold was analysed by 50 g fire assay and
the other elements including copper and iron were analysed by
ICP-MS or ICP-OES following a four acid digest. The sample
preparation and assay techniques are of international industry
standard and can be considered total.
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- For geophysical tools, spectrometers,
handheld XRF instruments, etc, the parameters used in determining
the analysis including instrument make and model, reading times,
calibrations factors applied and their derivation, etc.
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- No geophysical tools were used for any
analysis reported herein. Magnetic susceptibility readings are used
in magnetic modelling but are not used to estimate magnetite or Fe
content.
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- Nature of quality control procedures
adopted (e.g. standards, blanks, duplicates, external laboratory
checks) and whether acceptable levels of accuracy (ie lack of bias)
and precision have been established.
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- Quality control completed by RTG included
analysis of standards, blanks, and duplicates. Commercial Certified
Reference Materials were inserted into sample batches every
40th sample. A blank sample was inserted every
20th sample; the blank sample material has been sourced
and prepared from a local quarry. One in every 20 core samples is
cut into 2 quarter core samples which were submitted independently
with their own sample numbers. In addition, Intertek conducted
their own extensive check sampling as part of their own internal
QAQC processes which is reported in the assay sheets. A record of
results from all duplicates, blanks and standards is maintained for
ongoing QA/QC assessment. Examination of all the QAQC sample data
indicates satisfactory performance of field sampling protocols and
the assay laboratory.
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Verification of
sampling and assaying
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- The verification of significant intersections by
either independent or alternative company
personnel.
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- Significant mineralisation intersections were
verified by alternative company personnel.
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- The use of twinned holes.
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- No twinned holes have been drilled.
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- Documentation of primary data, data entry
procedures, data verification, data storage (physical and
electronic) protocols.
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- Data documentation, verification and storage
is conducted in accordance with RTG's Standard Operating Procedures
Manual for the Mabilo Project. The diamond drill core is manually
logged in significant detail in a number of separate Excel template
logging sheets. Logging is recorded manually on logging sheets and
transcribed into protected Excel spreadsheet templates or entered
directly into the Excel templates. The data are validated by both
the Project Geologist and the company Database Manager and uploaded
to the dedicated project database where they are merged with assay
results reported digitally by the laboratory. Hard copies of all
logging sheets are kept at the Project office in Daet.
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- Discuss any adjustment to assay
data.
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- No adjustments have been made to assay
data.
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Location of
data points
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- Accuracy and quality of surveys used to locate
drill holes (collar and down-hole surveys), trenches, mine workings
and other locations used in Mineral Resource
estimation.
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- Drill-hole collars are initially surveyed with a
hand-held GPS with an accuracy of approximately +/- 5 m. Completed
holes are surveyed by an independent qualified surveyor on a
periodic basis using standard differential GPS (DGPS) equipment
achieving sub-decimetre accuracy in horizontal and vertical
position.
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- Specification of the grid system
used.
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- Drill collars are surveyed in UTM WGS84 Zone
51N grid.
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- Quality and adequacy of topographic
control.
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- The Mabilo project area is relatively flat
with total variation in topography less than 15 m. Topographic
control is provided by DGPS surveying.
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Data spacing
and distribution
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- Data spacing for reporting of Exploration
Results.
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- Drill holes are
planned on a nominal grid with 20 m between drill holes on 40 m
spaced lines.
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- Whether the data spacing and distribution
is sufficient to establish the degree of geological and grade
continuity appropriate for the Mineral Resource and Ore Reserve
estimation procedure(s) and classifications applied.
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- The drill hole spacing was designed to
determine the continuity and extent of the mineralised skarn zones.
Based on statistical assessment of drill results to date, the
nominal 40 x 20 m drill hole spacing is sufficient to support
Mineral Resource estimation.
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- Whether sample compositing has been
applied.
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- No compositing of intervals in the field was
undertaken
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Orientation of
data in relation to geological structure
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- Whether the
orientation of sampling achieves unbiased sampling of possible
structures and the extent to which this is known, considering the
deposit type.
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- No bias
attributable to orientation of sampling upgrading of results has
been identified.
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- If the relationship between the drilling
orientation and the orientation of key mineralised structures is
considered to have introduced a sampling bias, this should be
assessed and reported if material.
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- No bias attributable to orientation of
sampling upgrading of results has been identified.
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Sample
security
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- The measures
taken to ensure sample security.
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- Chain of custody is
managed by RTG employees. Samples were stored in secure storage
from the time of drilling, through gathering and splitting.
Remaining core is kept in a secure compound at the Company regional
office in Daet town and guarded at night. Samples are sent directly
from the core shed to the laboratory packed in secured and sealed
plastic drums using either Company vehicles or a local transport
company. A standard Chain of Custody form is signed by the driver
responsible for transporting the samples upon receipt of samples at
the core yard and is signed by an employee of the laboratory on
receipt of the samples at the laboratory. Completed forms are
returned to the Company for filing.
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Audits or
reviews
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- The results of any audits or reviews of sampling
techniques and data.
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- The sampling techniques and QA/QC data are reviewed
on an ongoing basis by Company management and independent
consultants.
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