REG - First Tin PLC - Mineral Resource Estimate Upgrade at Taronga
14/09/2023 07:15
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RNS Number : 3792M First Tin PLC 14 September 2023
14 September 2023
First Tin Plc
("First Tin" or "the Company")
Mineral Resource Estimate Upgrade at Taronga Tin Project
First Tin PLC ("First Tin"), a tin development company with advanced, low
capex projects in Germany and Australia, is pleased to announce an updated
Mineral Resource Estimate ("MRE") for its 100% owned Taronga Tin Project in
Australia, completed by independent geological consultants H&S Consultants
Pty Ltd ("H&SC"). The MRE has been prepared in accordance with the 2012
JORC Code & Guidelines.
The updated MRE is reported using a 0.05% tin ("Sn") cut-off to a maximum
depth of 300m below surface (650mRL):
Category Tonnage (Million) Grade (% Sn) Tin (Tonnes)
Measured 33.0 0.13 44,200
Indicated 38.9 0.11 42,000
Sub-Total (M&I) 71.9 0.12 86,200
Inferred 61.1 0.09 61,100
TOTAL 133.0 0.10 138,300
(minor rounding errors)
This is a substantial 240% increase in size on the previous MRE announced by
Aus Tin Mining Ltd in 2014 which was calculated using a 0.10% Sn cut-off.
The lower cut-off for the updated Mineral Resource is based on revised
economic considerations including higher 3-year trailing tin prices, lower
AUD:USD exchange rates and preliminary estimates of mining, processing and
G&A costs.
A direct comparison with the 2014 MRE using a 0.10% Sn cut-off is:
2014 MRE H&SC 2023 MRE Percentage Change (%)
Tonnes (Million) Grade (%Sn) Tin (Tonnes) Tonnes (Million) Grade (%Sn) Tin (Tonnes)
Measured - - - 21.5 0.17 35,700 -
Indicated 26.9 0.17 45,200 16.5 0.16 26,000 (42.5)
Sub-Total 26.9 0.17 45,200 38.0 0.16 61,700 36.5
Inferred 9.4 0.13 12,000 13.4 0.14 18,600 55
TOTAL 36.3 0.16 57,200 51.7 0.16 80,300 40.4
(minor rounding errors)
The comparison represents a 40% increase in total contained tin metal based on
the same cut-off. The difference is primarily due to:
* Exploration drilling by First Tin successfully extending the Mineral Resource
to the southwest of the existing estimate
* A new geological interpretation
* A reconfigured grade interpolation technique
A Measured Resource category has been included for the first time. This is
based on the successful hole twinning drill programme conducted by First Tin
which validated the Newmont drilling data alongside a more in-depth study of
the Newmont QAQC data which confirmed the reliability of the historic drilling
data.
A grade-tonnage table is included as Table 1 with a graphical representation
shown as Figure 1.
First Tin CEO Thomas Buenger said: "The 2023 MRE represents the culmination of
a highly successful drill campaign at Taronga, which opened up new areas of
mineralisation and validated previous data. We are very pleased with the large
increase in contained tin and the addition of a Measured Resource category,
which provides further confidence in the MRE. The grade-tonnage curve shows
that the Mineral Resource Estimate is robust and that significant tonnages of
higher-grade material exist that will in turn reduce risk due to changing tin
prices."
The project is owned by First Tin's 100% owned Australian subsidiary, Taronga
Mines Pty Ltd ("TMPL").
Sn Cut off % Mt Sn % Sn Kt
0.025 197.3 0.082 161.8
0.04 157.0 0.095 149.1
0.05 133.0 0.104 138.3
0.06 111.4 0.113 125.9
0.07 92.6 0.123 113.8
0.08 76.0 0.134 101.9
0.09 62.4 0.145 90.5
0.1 51.5 0.156 80.3
0.125 32.0 0.183 58.6
0.15 20.5 0.209 42.9
0.2 8.7 0.261 22.7
0.25 3.8 0.315 11.9
0.3 1.7 0.37 6.1
0.5 0.1 0.589 0.7
Table 1: Tin Grade-Tonnage Table for Taronga
Figure 2 shows an oblique view of the tin block grade distribution for the
Taronga Mineral Resources (figure in local grid orientation). The black
ellipse highlights the additional resource discovered by First Tin.
Figure 3 demonstrates in an oblique view the distribution of Resource
Categories for the Taronga tin deposit (figures in local grid orientation).
All Resource Categories
Measured & Indicated
Measured
Figure 3: Distribution of Mineralisation by Category, Taronga
Enquiries:
First Tin Via SEC Newgate below
Thomas Buenger - Chief Executive Officer
Arlington Group Asset Management Limited (Financial Advisor and Joint Broker)
Simon Catt 020 7389 5016
WH Ireland Limited (Joint Broker)
Harry Ansell 020 7220 1670
SEC Newgate (Financial Communications)
Elisabeth Cowell / Molly Gretton FirstTin@secnewgate.co.uk
Notes to Editors
First Tin is an ethical, reliable, and sustainable tin production company led
by a team of renowned tin specialists. The Company is focused on becoming a
tin supplier in conflict-free, low political risk jurisdictions through the
rapid development of high value, low capex tin assets in Germany and
Australia.
Tin is a critical metal, vital in any plan to decarbonise and electrify the
world, yet Europe has very little supply. Rising demand, together with
shortages, is expected to lead tin to experience sustained deficit markets for
the foreseeable future. Its assets have been de-risked significantly, with
extensive work undertaken to date.
First Tin's goal is to use best-in-class environmental standards to bring two
tin mines into production in three years, providing provenance of supply to
support the current global clean energy and technological revolutions.
JORC Code, 2012 Edition - Table 1 Taronga Tin Project (TMPL)
Section 1 Sampling Techniques and Data
(Criteria in this section apply to all succeeding sections.)
Criteria JORC Code explanation Commentary
Sampling techniques · Nature and quality of sampling (eg cut channels, random chips, or · Sampling consisted of two surface drilling phases: Newmont 1979
specific specialised industry standard measurement tools appropriate to the to 1982 and Taronga Mines Pty Ltd (TMPL) 2022 to 2023.
minerals under investigation, such as down hole gamma sondes, or handheld XRF
instruments, etc). These examples should not be taken as limiting the broad · Diamond drilling (DD) was used to obtain 1m samples of NQ3/HQ3 core
meaning of sampling. which was sawn in half longitudinally. The half core was bagged and sent to a
commercial laboratory for sample prep and assay. This is industry standard
· Include reference to measures taken to ensure sample representivity work.
and the appropriate calibration of any measurement tools or systems used.
· The Newmont open hole percussion (OHP) and JACRO percussion
· Aspects of the determination of mineralisation that are Material to drilling was used to obtain 1m samples. (a JACRO percussion rig was used to
the Public Report. sample shallow areas with shallow angled drillholes).
· In cases where 'industry standard' work has been done this would be · The TMPL Reverse Circulation (RC) drilling was used to obtain 1m
relatively simple (eg 'reverse circulation drilling was used to obtain 1 m samples from a 4.5 inch diameter drill hole. This is industry standard work.
samples from which 3 kg was pulverised to produce a 30 g charge for fire
assay'). In other cases more explanation may be required, such as where there · To ensure sample representivity all diamond drilling was triple
is coarse gold that has inherent sampling problems. Unusual commodities or tube.
mineralisation types (eg submarine nodules) may warrant disclosure of detailed
information. · To ensure sample representivity appropriate compressors were used
for the OHP/JACRO/RC drilling to lift all the sample and prevent water
inflows.
· Mineralisation is characterised as sheeted quartz veins with minor
cassiterite, arsenopyrite and chalcopyrite in hornfelsed metasediments. Veins
are often hairline fractures and there is no obviously visible pervasive
alteration associated with the hornfelsing. No discrete boundaries to the
mineralisation are known to exist. All drilling samples were analysed and
hence no prior determination of mineralisation was made.
· Laboratory sample prep involved industry standard drying, weighing
and crushing followed by splitting (where sample size was too large) and
pulverising. For Newmont this was completed on site with analysis at a
commercial laboratory, whilst for TMPL the sample prep and analysis was
completed at a commercial laboratory. The subsequent pulp sample was analysed
by an appropriate industry standard method for the time.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, rotary · Details of drilling for the general area:
air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or
Company Type No of Holes Metres
standard tube, depth of diamond tails, face-sampling bit or other type, Newmont DD 173 25,718.8
whether core is oriented and if so, by what method, etc). OHP 81 5,573.5
JACRO 97 3,771.0
Total 351 35,063.3
TMPL Type No of Holes Metres
DD 13 1,619.2
RC 46 4,714.0
Total 59 6,333.2
Combined Type No of Holes Metres
DD 186 27,338.0
OHP 81 5,573.5
RC 46 4,714.0
JACRO 97 3,771.0
Total 410 41,396.5
Newmont
· DD were collared HQ or with OHP, reducing to NQ triple tube once
solid ground was met. Triple tube drilling was employed to maximise core
recovery and minimise the loss of cassiterite. Core was not oriented.
· OHP drilling was originally undertaken using a high pressure Schramm
rig. Later percussion drilling, including all drillholes in the PG 400 series,
used a high pressure T-3 rig with a 140mm tungsten bit. The rig was equipped
with a primary cyclone connected to a manifold at the collar for sample
recovery. A secondary Donaldson filter was attached to the outlet of the
primary cyclone to collect minus 5 micrometre dust.
· A modified JACRO percussion rig equipped with a vacuum sample
recovery system was used exclusively for Newmont's shallow angle drilling.
TMPL
· Diamond drilling was undertaken using an HQ bit with a soft matrix.
Triple tube drill rods were used to ensure good core recovery and avoid
washing out of cassiterite. Core was not oriented.
· Percussion drilling was undertaken using a face sampling 4.5 inch
"Black Diamond" hammer, 137mm PED (polycarbonate diamond) bit and a 4.5 inch,
6m stainless steel rod. A tight shroud (3mm gap) ensured the holes remained
as straight as possible. A 350psi, 900cfm compressor was used to keep holes
dry and ensure all heavy minerals such as cassiterite are recovered.
Drill sample recovery · Method of recording and assessing core and chip sample recoveries and · All core intervals are measured and compared with the drillers marks
results assessed. to determine actual recovery. Recovery was generally 100% apart from isolated
intervals with poor ground conditions, generally either near surface or in
· Measures taken to maximise sample recovery and ensure representative fault zones. Average recovery for Newmont DD is 97.3% with average recovery
nature of the samples. for TMPL DD of 96.8%
· Whether a relationship exists between sample recovery and grade and · All RC and OHP samples were weighed at site. This gives a good idea
whether sample bias may have occurred due to preferential loss/gain of as to recovery for the 1m intervals sampled as the density does not vary
fine/coarse material. significantly. Recovery for the OHP was estimated to be very good in
general. Semi quantitative analysis of the TMPL weighed RC samples indicated
an average recovery >90%.
· No information on the JACRO holes' recovery was available.
· All diamond drilling used triple tube rods to maximise sample
recovery.
· There is some speculation by TMPL that the drilling and core cutting
processes may have resulted in small scale loss of tin through washout
associated with the vein margins and very small vughs in the tin-bearing
veins. Conclusive evidence for this is lacking.
· For the percussion drilling a high pressure and volume compressor was
used to ensure good sample return and to keep holes dry. No significant water
was encountered meaning sample quality was good. The hole was cleaned out with
compressed air after every rod change and no significant volume of material
was returned via this process.
· No relationship can be seen between recovery and tin grade. No sample
bias is noted.
· Previous work by Mining One suggested that there was downhole
smearing of tin grade associated with the JACRO drilling based on
geostatistical work, but a review of the Newmont JACRO/DD twin hole drilling
indicated no bias; check modelling without the JACRO drilling indicated no
difference in global block grades. Visual inspection might suggest possible
smearing but it is difficult to be certain. The JACRO holes were included in
the Mineral Resource estimate.
Logging · Whether core and chip samples have been geologically and · All samples have been geologically logged to a level of detail to
geotechnically logged to a level of detail to support appropriate Mineral support appropriate mineral estimation, mining, and metallurgical studies.
Resource estimation, mining studies and metallurgical studies.
· The TMPL diamond holes have been geotechnically logged to a level of
· Whether logging is qualitative or quantitative in nature. Core (or detail to support appropriate mineral estimation, mining, and metallurgical
costean, channel, etc) photography. studies
· The total length and percentage of the relevant intersections logged. · All drill core logging is both qualitative and quantitative in
nature, with the TMPL logging following a strict set of guidelines. The entire
length each hole has been logged.
· The Newmont drilling was completed as hardcopy logsheets which were
transcribed into a digital format in 2013. All TMPL core was digitally logged
and has been photographed.
· All RC, OHP and JACRO logging is semi-quantitative in nature, with
the TMPL RC drilling following a strict set of guidelines, with percentage
estimates made. Representative sub-samples were collected, sieved and
selectively panned to visually estimate heavy mineral content. A sub-set of
rock chips for each RC sample are kept in chip-trays for reference and stored
on site.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core Newmont drilling sample prep
taken.
· NQ core was sawn in half longitudinally at 1m intervals with one half
· If non-core, whether riffled, tube sampled, rotary split, etc and dispatched to Analabs Pty Limited ("Analabs") in Perth, Australia for assay.
whether sampled wet or dry. The half core selected for assay was crushed (size unknown) then ground to 500
microns from which a 100g sample was split and pulverized to less than 75
· For all sample types, the nature, quality and appropriateness of the microns. A lab duplicate of each tenth sample was split and pulverised to
sample preparation technique. check sample preparation and assaying reliability. These were appropriate,
industry standard, sampling and sample preparation techniques for the time.
· Quality control procedures adopted for all sub-sampling stages to
maximise representivity of samples. · All 1m percussion drill samples were prepared for assay on site using
four stages of size reduction comprising jaw crusher, rolls crusher, disc
· Measures taken to ensure that the sampling is representative of the grinder and ring grinder (pulveriser), with sample splitting between stages in
in situ material collected, including for instance results for field accord with Pierre Gy's "Particulate Sampling Procedures". The pulverised
duplicate/second-half sampling. material was dispatched to Analabs in Perth for assay.
· Whether sample sizes are appropriate to the grain size of the · A duplicate of each tenth sample was split and pulverised to check
material being sampled. sample preparation and assaying reliability. These were appropriate, industry
standard, sampling and sample preparation techniques at the time.
· Duplicate samples showed that a majority of duplicate Sn assays
deviated by less than 2.5% relative to perfect correlation.
TMPL drilling sample prep
· HQ core was sawn in half longitudinally after fitting together of
core across drillers breaks and a reference line marked on the core. A
consistent side of the core is taken for sampling with the samples sent to the
ALS laboratory in Brisbane, Australia.
· All RC cuttings were weighed then riffle split on site to obtain
between 3kg and 5kg of sample. All samples are dry. The sub-sample is sent to
the ALS laboratory in Brisbane.
· Core and RC chip sample prep consists of crushing to 70% passing 6mm
with splitting used if crushed sample is over 3kg. The entire sample or
sub-sample is then pulverized in a mill to 85% finer than 75µm.
· Prior to dispatch of samples, the following QAQC samples are added:
o Field duplicates are added at the rate of 1 in 20 samples for RC.
These are riffle split from the original sample on site.
o For diamond drilling, the half core is split into two quarter cores
every 1 in 20 samples and these are sent as field duplicates.
· Sample sizes are considered appropriate for the material being
sampled as the tin mineralisation occurs as cassiterite (SnO(2)) within
sub-vertical veins that are between 0.05mm and 0.5cm wide (rarely to 5cm) and
cassiterite crystals are smaller than the vein width. Vein density varies from
about 5/m to greater than 20/m and hence several veins are sampled in each
metre. This compares favourably with the sample size that is approximately
10,000 cm(3) for RC and 3,200cm(3) for HQ core before sub-sampling.
· No independent sizing checks were completed. The ALS Lab completed
its own internal checks and reported the results.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and Newmont
laboratory procedures used and whether the technique is considered partial or
total. · All Sn assays were performed by taking 10g samples from the 100g
pulverised samples. The samples were analysed for Sn using pressed powder
· For geophysical tools, spectrometers, handheld XRF instruments, etc, X-ray fluorescence at Analabs. Pressed powder X-ray fluorescence was the
the parameters used in determining the analysis including instrument make and industry standard for Sn analysis at the time.
model, reading times, calibrations factors applied and their derivation, etc.
· Comparison of Sn assays of samples from diamond drill and percussion
· Nature of quality control procedures adopted (eg standards, blanks, holes was good and no bias between the two sets of analyses is evident.
duplicates, external laboratory checks) and whether acceptable levels of
accuracy (ie lack of bias) and precision have been established. · For every 30 samples, four standards were inserted on rotation. In
addition, every tenth sample was lab duplicate assayed.
· Selected samples were check assayed at other laboratories and using
other assay methods, including an XRF method developed by Cleveland Tin
Limited in Tasmania which was a significant Australian tin producer at the
time. The checks confirmed that Analab's procedures were satisfactory and that
sample preparation and assay quality were consistently maintained by Analabs.
TMPL
· All Sn assays were performed on a 0.1g sub-sample of the pulverised
and mixed material, which was taken and fused with lithium borate. The fused
bead is then analysed by a mass spectrometer using method ME-MS85 which
reports Sn, W, Ta and Nb. This returns a total tin content, including tin as
cassiterite. Over limit assays of tin are re-analysed using method ME-XRF15b
which involves fusion with lithium metaborate with a lithium tetraborate flux
containing 20% NaNO(3) with an XRF finish.
· Other elements are analysed by method ME-ICP61 using a 0.25g
sub-sample. This involves a 4 acid digest with an ICP-AES finish. This is an
industry standard technique for a suite of 34 elements, including tin, copper,
arsenic, sulphur and silver. The tin assay is only acid soluble tin and thus
can be subtracted from the fusion tin assays to obtain tin as cassiterite.
Acid soluble tin is generally associated with stannite and in the lattice of
silicates. The acid soluble tin is generally insignificant in relation to tin
as cassiterite at Taronga.
· Prior to dispatch of samples, the following QAQC samples were added:
o 3 Certified Reference Materials, representative of the expected grades
were inserted into the sample suite at the rate of 1 in 40 samples.
o Coarse Blanks were inserted at the rate of 1 in 40 samples.
· If results for the CRMs indicated a >5% assay error, the sample
was compared with other CRMs in the same batch. If other CRMs indicated
similar errors the lab was contacted to review.
· All QAQC data is within acceptable limits.
Verification of sampling and assaying · The verification of significant intersections by either independent Newmont
or alternative company personnel.
· There is no information on any verification of significant
· The use of twinned holes. intersections by either independent or alternative company personnel.
· Documentation of primary data, data entry procedures, data · Geological interpretations were made using cross-sections and level
verification, data storage (physical and electronic) protocols. plans. Mining One accepted the Northern Zone 101 and the Southern Zones of
Payback, Payback Extended, Hillside and Hillside Extended were interpreted on
· Discuss any adjustment to assay data. cross-sections as reported in a Pre-feasibility Study prepared by Newmont
Holdings Pty Ltd in 1982.
· A small number of twinned holes (10 pairs) were completed by Newmont
and comparison of length weighted intercepts indicated no obvious bias.
· There is no information available on documentation of primary data,
data entry procedures, data verification, data storage. It is assumed all data
was paper copies subsequently transcribed by AusTinMining using a data entry
bureau service.
· There are no reports of any adjustments made to the assay data,
although it appears that some transcribed assay data was limited to 2 decimal
places rendering very low grade data as zeroes.
TMPL
· Simon Tear, a director of independent consultants H&S Consultants
Pty Ltd, has viewed and verified all core from 6 DD holes.
· Twinning of previous Newmont drillholes has included:
o 11 TMPL DD twins of Newmont DD Holes
o 2 TMPL DD twins of Newmont OPH holes
o 5 TMPL RC twins of Newmont OPH holes
· Twin holes were selected to represent all zones of mineralisation and
the length of the known deposit.
· All results are within acceptable limits taking into account any
possible nugget effect resulting from coarse cassiterite (noticed in three
drill intersections). Due to the small number of high grade veins, top cutting
of the high grade assays has a negligible effect on the overall grade.
· All data is recorded on site in MSExcel spreadsheets and this is
later transferred to an MSAccess database - the main data repository via cut
and paste. Detailed protocols for data recording, logging codes etc are used.
The assay data is received from the laboratory (ALS) via csv and pdf files
with attached certificates. This may also be downloaded directly from the ALS
website by the senior project geologist. The assay data is then merged using
sample number. Detailed protocols for data recording, logging codes etc are
used.
· Assays below lower detection limits were substituted with half lower
detection limit.
Location of data points · Accuracy and quality of surveys used to locate drill holes (collar Newmont
and down-hole surveys), trenches, mine workings and other locations used in
Mineral Resource estimation. · Drill hole collars were located by theodolite traverses by qualified
surveyors.
· Specification of the grid system used.
· A local grid parallel to the strike of the mineralisation was used.
· Quality and adequacy of topographic control. Local grid north has a bearing of 055.103(O) true. A 3.5km baseline was
surveyed with surveyed cross-lines at 100m intervals.
· Holes were surveyed down-hole for azimuth and dip using down-hole
cameras with a range of downhole depths from 15m to 50m. Given the generally
non-magnetic nature of the mineralisation and the host rocks, this was a
reasonable survey method.
· Topographic maps at 1:1000 scale were prepared by Australian Aerial
Mapping. The maps were related to the local grid.
TMPL
· All hole collars are accurately surveyed post drilling with a RTK GPS
(+/-0.1m accuracy).
· All DD are surveyed downhole at 30m intervals using Axis Champ
Gyroscope.
· All RC holes are surveyed at 30m intervals using a Trushot Digital
survey tool.
· The grid system used is GDA94, zone 56.
· Topography is obtained via a LiDAR survey flown in late 2022 and is
to sub-10cm accuracy.
· All data was converted to local grid by H&SC for resource
estimation work.
· H&SC undertook field measurement of 20 drill collars from both
phases using a hand held GPS. Average discrepancy was 0.5m in the easting
and 0.5m in the northing.
Data spacing and distribution · Data spacing for reporting of Exploration Results. · The Newmont drilling was nominally on a 50m by 50m pattern with 25m
infill drilling in some areas.
· Whether the data spacing and distribution is sufficient to establish
the degree of geological and grade continuity appropriate for the Mineral · The TMPL drilling completed in 2022/3 was nominally at the same 50m
Resource and Ore Reserve estimation procedure(s) and classifications applied. by 50m spacing.
· Whether sample compositing has been applied. · Virtually all downhole sampling was 1m intervals from surface.
· Data spacing is sufficient to establish the geological and grade
continuity appropriate for the Mineral Resource estimation and classification
procedures applied for this report.
· No sample compositing has been applied.
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · The drilling is oriented at 90° to the strike of the sheeted vein
possible structures and the extent to which this is known, considering the system.
deposit type.
· The vein system is sub-vertical and the drilling is angled between
· If the relationship between the drilling orientation and the -25° and -60° to be as close as possible to cutting across the veins at
orientation of key mineralised structures is considered to have introduced a 90°. Due to difficulties drilling at very shallow angles, especially with RC,
sampling bias, this should be assessed and reported if material. a default angle of -60° was adopted for the later TMPL drillholes.
· As drilling was designed to cut the main sheeted vein system at as
high an angle as possible, the potential for any introduced sampling bias is
considered minor.
Sample security · The measures taken to ensure sample security. · Samples of Newmont drill core and percussion chips were bagged and
tagged and shipped to the assay laboratory by independent third party
transport. No further information is available.
· A chain of custody was maintained for all TMPL drilling.
· TMPL samples were placed in calico bags in groups of seven which were
then wrapped in opaque polyweave bags, stacked on a palette and wrapped with
pallet wrap and tape.
· Samples sent to the lab via registered courier with tracking
capabilities.
· Samples arrive at the lab and were cross checked with a separate
despatch form (electronically sent to ALS).
Audits or reviews · The results of any audits or reviews of sampling techniques and data. · An review of sampling procedures and protocols was completed by Simon
Tear of independent consultants H&S Consultants Pty Ltd whilst drilling
was in progress, with some recommendations.
Newmont
· DD were collared HQ or with OHP, reducing to NQ triple tube once
solid ground was met. Triple tube drilling was employed to maximise core
recovery and minimise the loss of cassiterite. Core was not oriented.
· OHP drilling was originally undertaken using a high pressure Schramm
rig. Later percussion drilling, including all drillholes in the PG 400 series,
used a high pressure T-3 rig with a 140mm tungsten bit. The rig was equipped
with a primary cyclone connected to a manifold at the collar for sample
recovery. A secondary Donaldson filter was attached to the outlet of the
primary cyclone to collect minus 5 micrometre dust.
· A modified JACRO percussion rig equipped with a vacuum sample
recovery system was used exclusively for Newmont's shallow angle drilling.
TMPL
· Diamond drilling was undertaken using an HQ bit with a soft matrix.
Triple tube drill rods were used to ensure good core recovery and avoid
washing out of cassiterite. Core was not oriented.
· Percussion drilling was undertaken using a face sampling 4.5 inch
"Black Diamond" hammer, 137mm PED (polycarbonate diamond) bit and a 4.5 inch,
6m stainless steel rod. A tight shroud (3mm gap) ensured the holes remained
as straight as possible. A 350psi, 900cfm compressor was used to keep holes
dry and ensure all heavy minerals such as cassiterite are recovered.
Drill sample recovery
· Method of recording and assessing core and chip sample recoveries and
results assessed.
· Measures taken to maximise sample recovery and ensure representative
nature of the samples.
· 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.
· All core intervals are measured and compared with the drillers marks
to determine actual recovery. Recovery was generally 100% apart from isolated
intervals with poor ground conditions, generally either near surface or in
fault zones. Average recovery for Newmont DD is 97.3% with average recovery
for TMPL DD of 96.8%
· All RC and OHP samples were weighed at site. This gives a good idea
as to recovery for the 1m intervals sampled as the density does not vary
significantly. Recovery for the OHP was estimated to be very good in
general. Semi quantitative analysis of the TMPL weighed RC samples indicated
an average recovery >90%.
· No information on the JACRO holes' recovery was available.
· All diamond drilling used triple tube rods to maximise sample
recovery.
· There is some speculation by TMPL that the drilling and core cutting
processes may have resulted in small scale loss of tin through washout
associated with the vein margins and very small vughs in the tin-bearing
veins. Conclusive evidence for this is lacking.
· For the percussion drilling a high pressure and volume compressor was
used to ensure good sample return and to keep holes dry. No significant water
was encountered meaning sample quality was good. The hole was cleaned out with
compressed air after every rod change and no significant volume of material
was returned via this process.
· No relationship can be seen between recovery and tin grade. No sample
bias is noted.
· Previous work by Mining One suggested that there was downhole
smearing of tin grade associated with the JACRO drilling based on
geostatistical work, but a review of the Newmont JACRO/DD twin hole drilling
indicated no bias; check modelling without the JACRO drilling indicated no
difference in global block grades. Visual inspection might suggest possible
smearing but it is difficult to be certain. The JACRO holes were included in
the Mineral Resource estimate.
Logging
· 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.
· Whether logging is qualitative or quantitative in nature. Core (or
costean, channel, etc) photography.
· The total length and percentage of the relevant intersections logged.
· All samples have been geologically logged to a level of detail to
support appropriate mineral estimation, mining, and metallurgical studies.
· The TMPL diamond holes have been geotechnically logged to a level of
detail to support appropriate mineral estimation, mining, and metallurgical
studies
· All drill core logging is both qualitative and quantitative in
nature, with the TMPL logging following a strict set of guidelines. The entire
length each hole has been logged.
· The Newmont drilling was completed as hardcopy logsheets which were
transcribed into a digital format in 2013. All TMPL core was digitally logged
and has been photographed.
· All RC, OHP and JACRO logging is semi-quantitative in nature, with
the TMPL RC drilling following a strict set of guidelines, with percentage
estimates made. Representative sub-samples were collected, sieved and
selectively panned to visually estimate heavy mineral content. A sub-set of
rock chips for each RC sample are kept in chip-trays for reference and stored
on site.
Sub-sampling techniques and sample preparation
· If core, whether cut or sawn and whether quarter, half or all core
taken.
· If non-core, whether riffled, tube sampled, rotary split, etc and
whether sampled wet or dry.
· For all sample types, the nature, quality and appropriateness of the
sample preparation technique.
· Quality control procedures adopted for all sub-sampling stages to
maximise representivity of samples.
· 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.
· Whether sample sizes are appropriate to the grain size of the
material being sampled.
Newmont drilling sample prep
· NQ core was sawn in half longitudinally at 1m intervals with one half
dispatched to Analabs Pty Limited ("Analabs") in Perth, Australia for assay.
The half core selected for assay was crushed (size unknown) then ground to 500
microns from which a 100g sample was split and pulverized to less than 75
microns. A lab duplicate of each tenth sample was split and pulverised to
check sample preparation and assaying reliability. These were appropriate,
industry standard, sampling and sample preparation techniques for the time.
· All 1m percussion drill samples were prepared for assay on site using
four stages of size reduction comprising jaw crusher, rolls crusher, disc
grinder and ring grinder (pulveriser), with sample splitting between stages in
accord with Pierre Gy's "Particulate Sampling Procedures". The pulverised
material was dispatched to Analabs in Perth for assay.
· A duplicate of each tenth sample was split and pulverised to check
sample preparation and assaying reliability. These were appropriate, industry
standard, sampling and sample preparation techniques at the time.
· Duplicate samples showed that a majority of duplicate Sn assays
deviated by less than 2.5% relative to perfect correlation.
TMPL drilling sample prep
· HQ core was sawn in half longitudinally after fitting together of
core across drillers breaks and a reference line marked on the core. A
consistent side of the core is taken for sampling with the samples sent to the
ALS laboratory in Brisbane, Australia.
· All RC cuttings were weighed then riffle split on site to obtain
between 3kg and 5kg of sample. All samples are dry. The sub-sample is sent to
the ALS laboratory in Brisbane.
· Core and RC chip sample prep consists of crushing to 70% passing 6mm
with splitting used if crushed sample is over 3kg. The entire sample or
sub-sample is then pulverized in a mill to 85% finer than 75µm.
· Prior to dispatch of samples, the following QAQC samples are added:
o Field duplicates are added at the rate of 1 in 20 samples for RC.
These are riffle split from the original sample on site.
o For diamond drilling, the half core is split into two quarter cores
every 1 in 20 samples and these are sent as field duplicates.
· Sample sizes are considered appropriate for the material being
sampled as the tin mineralisation occurs as cassiterite (SnO(2)) within
sub-vertical veins that are between 0.05mm and 0.5cm wide (rarely to 5cm) and
cassiterite crystals are smaller than the vein width. Vein density varies from
about 5/m to greater than 20/m and hence several veins are sampled in each
metre. This compares favourably with the sample size that is approximately
10,000 cm(3) for RC and 3,200cm(3) for HQ core before sub-sampling.
· No independent sizing checks were completed. The ALS Lab completed
its own internal checks and reported the results.
Quality of assay data and laboratory tests
· The nature, quality and appropriateness of the assaying and
laboratory procedures used and whether the technique is considered partial or
total.
· 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.
· Nature of quality control procedures adopted (eg standards, blanks,
duplicates, external laboratory checks) and whether acceptable levels of
accuracy (ie lack of bias) and precision have been established.
Newmont
· All Sn assays were performed by taking 10g samples from the 100g
pulverised samples. The samples were analysed for Sn using pressed powder
X-ray fluorescence at Analabs. Pressed powder X-ray fluorescence was the
industry standard for Sn analysis at the time.
· Comparison of Sn assays of samples from diamond drill and percussion
holes was good and no bias between the two sets of analyses is evident.
· For every 30 samples, four standards were inserted on rotation. In
addition, every tenth sample was lab duplicate assayed.
· Selected samples were check assayed at other laboratories and using
other assay methods, including an XRF method developed by Cleveland Tin
Limited in Tasmania which was a significant Australian tin producer at the
time. The checks confirmed that Analab's procedures were satisfactory and that
sample preparation and assay quality were consistently maintained by Analabs.
TMPL
· All Sn assays were performed on a 0.1g sub-sample of the pulverised
and mixed material, which was taken and fused with lithium borate. The fused
bead is then analysed by a mass spectrometer using method ME-MS85 which
reports Sn, W, Ta and Nb. This returns a total tin content, including tin as
cassiterite. Over limit assays of tin are re-analysed using method ME-XRF15b
which involves fusion with lithium metaborate with a lithium tetraborate flux
containing 20% NaNO(3) with an XRF finish.
· Other elements are analysed by method ME-ICP61 using a 0.25g
sub-sample. This involves a 4 acid digest with an ICP-AES finish. This is an
industry standard technique for a suite of 34 elements, including tin, copper,
arsenic, sulphur and silver. The tin assay is only acid soluble tin and thus
can be subtracted from the fusion tin assays to obtain tin as cassiterite.
Acid soluble tin is generally associated with stannite and in the lattice of
silicates. The acid soluble tin is generally insignificant in relation to tin
as cassiterite at Taronga.
· Prior to dispatch of samples, the following QAQC samples were added:
o 3 Certified Reference Materials, representative of the expected grades
were inserted into the sample suite at the rate of 1 in 40 samples.
o Coarse Blanks were inserted at the rate of 1 in 40 samples.
· If results for the CRMs indicated a >5% assay error, the sample
was compared with other CRMs in the same batch. If other CRMs indicated
similar errors the lab was contacted to review.
· All QAQC data is within acceptable limits.
Verification of sampling and assaying
· The verification of significant intersections by either independent
or alternative company personnel.
· The use of twinned holes.
· Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic) protocols.
· Discuss any adjustment to assay data.
Newmont
· There is no information on any verification of significant
intersections by either independent or alternative company personnel.
· Geological interpretations were made using cross-sections and level
plans. Mining One accepted the Northern Zone 101 and the Southern Zones of
Payback, Payback Extended, Hillside and Hillside Extended were interpreted on
cross-sections as reported in a Pre-feasibility Study prepared by Newmont
Holdings Pty Ltd in 1982.
· A small number of twinned holes (10 pairs) were completed by Newmont
and comparison of length weighted intercepts indicated no obvious bias.
· There is no information available on documentation of primary data,
data entry procedures, data verification, data storage. It is assumed all data
was paper copies subsequently transcribed by AusTinMining using a data entry
bureau service.
· There are no reports of any adjustments made to the assay data,
although it appears that some transcribed assay data was limited to 2 decimal
places rendering very low grade data as zeroes.
TMPL
· Simon Tear, a director of independent consultants H&S Consultants
Pty Ltd, has viewed and verified all core from 6 DD holes.
· Twinning of previous Newmont drillholes has included:
o 11 TMPL DD twins of Newmont DD Holes
o 2 TMPL DD twins of Newmont OPH holes
o 5 TMPL RC twins of Newmont OPH holes
· Twin holes were selected to represent all zones of mineralisation and
the length of the known deposit.
· All results are within acceptable limits taking into account any
possible nugget effect resulting from coarse cassiterite (noticed in three
drill intersections). Due to the small number of high grade veins, top cutting
of the high grade assays has a negligible effect on the overall grade.
· All data is recorded on site in MSExcel spreadsheets and this is
later transferred to an MSAccess database - the main data repository via cut
and paste. Detailed protocols for data recording, logging codes etc are used.
The assay data is received from the laboratory (ALS) via csv and pdf files
with attached certificates. This may also be downloaded directly from the ALS
website by the senior project geologist. The assay data is then merged using
sample number. Detailed protocols for data recording, logging codes etc are
used.
· Assays below lower detection limits were substituted with half lower
detection limit.
Location of data points
· 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.
· Specification of the grid system used.
· Quality and adequacy of topographic control.
Newmont
· Drill hole collars were located by theodolite traverses by qualified
surveyors.
· A local grid parallel to the strike of the mineralisation was used.
Local grid north has a bearing of 055.103(O) true. A 3.5km baseline was
surveyed with surveyed cross-lines at 100m intervals.
· Holes were surveyed down-hole for azimuth and dip using down-hole
cameras with a range of downhole depths from 15m to 50m. Given the generally
non-magnetic nature of the mineralisation and the host rocks, this was a
reasonable survey method.
· Topographic maps at 1:1000 scale were prepared by Australian Aerial
Mapping. The maps were related to the local grid.
TMPL
· All hole collars are accurately surveyed post drilling with a RTK GPS
(+/-0.1m accuracy).
· All DD are surveyed downhole at 30m intervals using Axis Champ
Gyroscope.
· All RC holes are surveyed at 30m intervals using a Trushot Digital
survey tool.
· The grid system used is GDA94, zone 56.
· Topography is obtained via a LiDAR survey flown in late 2022 and is
to sub-10cm accuracy.
· All data was converted to local grid by H&SC for resource
estimation work.
· H&SC undertook field measurement of 20 drill collars from both
phases using a hand held GPS. Average discrepancy was 0.5m in the easting
and 0.5m in the northing.
Data spacing and distribution
· Data spacing for reporting of Exploration Results.
· 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.
· Whether sample compositing has been applied.
· The Newmont drilling was nominally on a 50m by 50m pattern with 25m
infill drilling in some areas.
· The TMPL drilling completed in 2022/3 was nominally at the same 50m
by 50m spacing.
· Virtually all downhole sampling was 1m intervals from surface.
· Data spacing is sufficient to establish the geological and grade
continuity appropriate for the Mineral Resource estimation and classification
procedures applied for this report.
· No sample compositing has been applied.
Orientation of data in relation to geological structure
· Whether the orientation of sampling achieves unbiased sampling of
possible structures and the extent to which this is known, considering the
deposit type.
· 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.
· The drilling is oriented at 90° to the strike of the sheeted vein
system.
· The vein system is sub-vertical and the drilling is angled between
-25° and -60° to be as close as possible to cutting across the veins at
90°. Due to difficulties drilling at very shallow angles, especially with RC,
a default angle of -60° was adopted for the later TMPL drillholes.
· As drilling was designed to cut the main sheeted vein system at as
high an angle as possible, the potential for any introduced sampling bias is
considered minor.
Sample security
· The measures taken to ensure sample security.
· Samples of Newmont drill core and percussion chips were bagged and
tagged and shipped to the assay laboratory by independent third party
transport. No further information is available.
· A chain of custody was maintained for all TMPL drilling.
· TMPL samples were placed in calico bags in groups of seven which were
then wrapped in opaque polyweave bags, stacked on a palette and wrapped with
pallet wrap and tape.
· Samples sent to the lab via registered courier with tracking
capabilities.
· Samples arrive at the lab and were cross checked with a separate
despatch form (electronically sent to ALS).
Audits or reviews
· The results of any audits or reviews of sampling techniques and data.
· An review of sampling procedures and protocols was completed by Simon
Tear of independent consultants H&S Consultants Pty Ltd whilst drilling
was in progress, with some recommendations.
Section 2 Reporting of Exploration Results
(Criteria listed in the preceding section also apply to this section.)
Criteria JORC Code explanation Commentary
Mineral tenement and land tenure status · Type, reference name/number, location and ownership including · The project is secured by two granted tenements: EL8407 and ML 1774,
agreements or material issues with third parties such as joint ventures, both of which are currently in good standing. These are held 100% by TMPL.
partnerships, overriding royalties, native title interests, historical sites,
wilderness or national park and environmental settings. · No joint ventures or other encumbrances are known. The underlying
properties are freehold land owned 100% by TMPL apart from a block of Crown
· The security of the tenure held at the time of reporting along with Land that covers part of the southern deposit area as defined by Newmont.
any known impediments to obtaining a licence to operate in the area.
· The Crown Land is the only land subject to Native Title. No Native
Title claims existed at the time the tenements were granted.
· No national parks, historical sites or environmental constraints are
known. Recent surveys have identified the "vulnerable" flora species Velvet
Wattle. This is currently being avoided as much as possible and is not
considered to be a major constraint moving forward.
· The only royalty is the state of NSW royalty of 4% on tin mined.
Exploration done by other parties · Acknowledgment and appraisal of exploration by other parties. · Detailed exploration and feasibility studies were undertaken by
Newmont between 1979 and 1984. These have been used where applicable.
· This work was undertaken to a high standard and all data is
considered to be usable.
Geology · Deposit type, geological setting and style of mineralisation. · The tin deposit is a sheeted vein style +/- copper-silver with
horizontally and vertically extensive veins of
quartz-mica-cassiterite-sulphide +/-fluorite-topaz occurring over a combined
area of up to 2,700m by 270m.
· The veins vary in thickness from less than 0.5mm to 100mm but are
generally between 1mm and 10mm thick and average about 20 veins per metre.
· The host rock is hornfels derived by contact metamorphism of Permian
aged metasediments by Triassic-aged granites.
· The source of mineralising fluids is interpreted to be an underlying
intrusion of the Triassic Mole Leucogranite, a reduced, highly fractionated, A
to I type granite. The metals of interest (Sn, Cu, Ag) are interpreted to have
been enriched in the late magmatic fluid of this granite via enrichment of
incompatible elements during fractional crystallisation. Breaching of the
magma chamber during brittle faulting in an ENE orientation, a structural
corridor, has tapped these enriched fluids which have subsequently deposited
the metals due to changing temperature and pressure conditions and/or mixing
with meteoric fluids.
Drill hole Information · A summary of all information material to the understanding of the · No Exploration Results are being reported.
exploration results including a tabulation of the following information for
all Material drill holes:
o easting and northing of the drill hole collar
o elevation or RL (Reduced Level - elevation above sea level in metres) of the
drill hole collar
o dip and azimuth of the hole
o down hole length and interception depth
o hole length.
· If the exclusion of this information is justified on the basis that
the information is not Material and this exclusion does not detract from the
understanding of the report, the Competent Person should clearly explain why
this is the case.
Data aggregation methods · In reporting Exploration Results, weighting averaging techniques, · No Exploration Results are being reported.
maximum and/or minimum grade truncations (eg cutting of high grades) and
cut-off grades are usually Material and should be stated.
· Where aggregate intercepts incorporate short lengths of high grade
results and longer lengths of low grade results, the procedure used for such
aggregation should be stated and some typical examples of such aggregations
should be shown in detail.
· The assumptions used for any reporting of metal equivalent values
should be clearly stated.
Relationship between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of · As mineralisation is sub-vertical and while holes dip at between
Exploration Results. -25° and -60°, actual true widths vary from 88% to 50% of interval widths.
· If the geometry of the mineralisation with respect to the drill hole · No Exploration Results are being reported.
angle is known, its nature should be reported.
· If it is not known and only the down hole lengths are reported, there
should be a clear statement to this effect (eg 'down hole length, true width
not known').
Diagrams · Appropriate maps and sections (with scales) and tabulations of · No Exploration Results are being reported.
intercepts should be included for any significant discovery being reported
These should include, but not be limited to a plan view of drill hole collar
locations and appropriate sectional views.
Balanced reporting · Where comprehensive reporting of all Exploration Results is not · No Exploration Results are being reported.
practicable, representative reporting of both low and high grades and/or
widths should be practiced to avoid misleading reporting of Exploration
Results.
Other substantive exploration data · Other exploration data, if meaningful and material, should be · A detailed feasibility study is currently in progress. Bulk samples
reported including (but not limited to): geological observations; geophysical have been collected for metallurgical testwork and the testwork has shown that
survey results; geochemical survey results; bulk samples - size and method of a saleable concentrate can be produced at reasonable recovery using simple off
treatment; metallurgical test results; bulk density, groundwater, geotechnical the shelf gravity techniques.
and rock characteristics; potential deleterious or contaminating substances.
Further work · The nature and scale of planned further work (eg tests for lateral · A definitive feasibility study is currently in progress. No further
extensions or depth extensions or large-scale step-out drilling). drilling is planned as part of that process.
· Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling areas,
provided this information is not commercially sensitive.
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 data has not been corrupted by, for · The Newmont drilling data was supplied by TMPL as an MSAccess
example, transcription or keying errors, between its initial collection and database which had been compiled by the previous holders of the property,
its use for Mineral Resource estimation purposes. AusTinMining. This data was re-imported into an MSAccess database to allow for
some error checking.
· Data validation procedures used.
· The TMPL recent drilling data was supplied as a series of CSV
files which H&SC imported into the same MSAccess database as used for the
Newmont drilling.
· TMPL digital logging process involves android based Lenovo Tab
M10 HD tablets. The tablet has a rugged plastic and rubber waterproof case and
requires a pin code to unlock. The tablet has various templates stored on it
for recording different data sets (RC logging, DDH logging, RQD's etc). All
templates are MSExcel spreadsheets and operate via manually typing in the data
on the tablet or utilizing pre-filled drop-down boxes.
· Validation of the Newmont drilling by H&SC included original
assay and logging sheet checks against the supplied digital data for a set of
13 randomly selected drillholes. Minor typographic errors were noted and
fixed. Some of the methodology of transcribing the hard copy data could be
improved.
· H&SC completed some independent validation of the new data to
ensure the drill hole database is internally consistent. Validation included
checking that no assays or geological logs occur beyond the end of hole and
that all drilled intervals have been geologically logged. The minimum and
maximum values of assays and density measurements were checked to ensure
values are within expected ranges. Further checks include testing for
duplicate samples and overlapping sampling or logging intervals.
· H&SC takes responsibility for the accuracy and reliability of
the data used in the Mineral Resource estimates.
· H&SC used the historic local N-S orthogonal grid for all
interpretation and modelling work. For subsequent mine planning studies this
work was rotated and converted to MGA94 Zone 56 using the Surpac 2 point grid
transformation option.
Site visits · Comment on any site visits undertaken by the Competent Person and the · Two site visits were completed by Simon Tear of H&SC, in
outcome of those visits. October 2022 during the recent drilling campaign and again in June 2023 to
review newly drilled diamond core and other aspects of the sample data
· If no site visits have been undertaken indicate why this is the case. collection phase.
· The October 2022 visit involved inspection of both ongoing
diamond and RC drilling operations. A check on collar coordinates for 20 holes
including both historic and recent holes was completed. A review of chip trays
for 2 RC drillholes was also undertaken. Inspection of the trial adit and its
recent TMPL sampling was also completed.
· The June 2023 visit involved inspection of 6 DD holes from the
recent hole twinning programme designed by TMPL to test previous results from
the Newmont drilling. The inspection confirmed the geology, mineralisation and
assay grades at Taronga as comprising thin, cassiterite-bearing veins, in a
sheeted vein system, hosted within hornfels rock.
Geological interpretation · Confidence in (or conversely, the uncertainty of ) the geological · The mineralisation comprises North Pit and South Pit zones with a
interpretation of the mineral deposit. relatively lower grade zone in between (partly the result of a lack of
drilling and a change in the host lithology with possibly a change in the
· Nature of the data used and of any assumptions made. rheological properties of the host).
· The effect, if any, of alternative interpretations on Mineral · The North Pit comprises two higher grade elongate tin zones with
Resource estimation. an enveloping zone of lower grade tin forming a single mass. Whilst the South
Pit comprises up to five distinct and well separated elongate tin-enriched
· The use of geology in guiding and controlling Mineral Resource zones with parallel strike and dip.
estimation.
· The host rock is the result of relatively uniform hornfelsing of
· The factors affecting continuity both of grade and geology. either siltstone or sandstone.
· Mineralisation consists of quartz-cassiterite veins from hairline
fractures to veins up to 5-10cm thick. Chalcopyrite and arsenopyrite
disseminations, blebs and veinlets are commonly associated with the
tin-bearing veins. Minor pyrite zones are occasionally visible.
· There is no obvious visible lithological or structural control to
the tin mineralisation, save for a broad NE/SW striking enriched zone,
presumably some form of structural corridor. The system has been interpreted
as a sheeted vein deposit.
· No geological interpretation per se has been completed as the tin
grades define the tin mineralization in the rather amorphous-looking hornfels.
Any wireframe for the tin mineralization would ultimately be a simple grade
shell.
· There is insufficient data to define with confidence any specific
or significant fault structure.
· A review of multi-element data from the recent drilling has
allowed for the interpretation of a sodium depletion zone corresponding with a
weak potassic enrichment as matching the definition of the tin mineralisation.
The study also highlighted a lithogeochemical difference between the host
rocks for the South and North Pits.
· An oxidation surface, reflecting both complete and partial
weathering, was developed by H&SC from logged historic and recent drilling
data, with support from the multielement assays. Confidence in the surface is
moderate as the data is incomplete and there is uncertainty as to whether
weathering has formed a broad, horizontal front roughly parallel to the
surface topography and/or that there are more isolated, penetrative fingers of
weathering to greater depths via fault structures.
Dimensions · The extent and variability of the Mineral Resource expressed as · The Mineral Resources have a strike length of around 2.7km in a
length (along strike or otherwise), plan width, and depth below surface to the north easterly (grid north) direction. The plan width of the resource varies
upper and lower limits of the Mineral Resource. from 200m to 400m with an average of around 270m. The upper limit of the
mineralisation is exposed with the fresh rock generally occurring around 20m
below surface and the lower limit of the Mineral Resources extends to an
approximate depth of 550m below surface (400mRL).
· The lower limit to the Mineral Resource is a direct function of
the depth limitations to the drilling in conjunction with the search
parameters. The mineralisation is open at depth and laterally to the
southwest, beyond the South Pit zone.
Estimation and modelling techniques · The nature and appropriateness of the estimation technique(s) applied · The drillhole database was composited with no constraints to 1m
and key assumptions, including treatment of extreme grade values, domaining, composites covering the whole of the prospect.
interpolation parameters and maximum distance of extrapolation from data
points. If a computer assisted estimation method was chosen include a · Ordinary Kriging (OK) with two search domains was used to
description of computer software and parameters used. complete the tin grade estimation using H&SC's in-house GS3M modelling
software. The geological interpretation and block model creation and
· The availability of check estimates, previous estimates and/or mine validation was completed using the Surpac mining software. H&SC considers
production records and whether the Mineral Resource estimate takes appropriate OK to be an appropriate estimation technique for the type of mineralisation
account of such data. and extent of data available. The tin composite data has a relatively low
coefficient of variation of approximately 1.6 (CV = standard deviation divided
· The assumptions made regarding recovery of by-products. by the mean).
· Estimation of deleterious elements or other non-grade variables of · Regression equations based on newly available assay data were
economic significance (eg sulphur for acid mine drainage characterisation). used to estimate missing copper, arsenic and sulphur composite values. The
arsenic and sulphur datasets are a lot smaller in number compared to the
· In the case of block model interpolation, the block size in relation copper and silver data. Correlation between the various elements was modest to
to the average sample spacing and the search employed. weak but generated regression equations based on the tin grade, using the
Conditional Expectation technique, resulted in plausible outcomes for Cu, As,
· Any assumptions behind modelling of selective mining units. Ag & S. It should be noted that the copper, arsenic, silver and sulphur
are not reported as part of the Mineral Resources and that the numbers are
· Any assumptions about correlation between variables. generated from less data than that used in the tin Mineral Resources; the
elements were modelled to allow for waste rock characterisation. OK was also
· Description of how the geological interpretation was used to control used to model these other elements.
the resource estimates.
· A total of 35,176 1m composites, excluding residuals (137), were
· Discussion of basis for using or not using grade cutting or capping. generated from the drillhole database and modelled for tin, copper, arsenic,
silver & sulphur.
· The process of validation, the checking process used, the comparison
of model data to drill hole data, and use of reconciliation data if available. · Grade interpolation was unconstrained, except by the search
parameters and the variography, in acknowledgement of the gradational nature
to the margins of the tin mineralisation and the abundance of peripheral
assays.
· There were very minor zones of unsampled core which were
generally surrounded by very low grades and therefore did not require the
insertion of very low grades. These areas were invariably allocated very low
block grades from the subsequent grade interpolation.
· The base of oxidation was treated as a soft boundary. No cover
surface was created as the mineralisation is outcropping and is exposed in
many places along its ridge line and flanks.
· No top-cutting was applied as extreme values were considered by
H&SC as not significant and therefore top-cutting was considered
unnecessary.
· An OK check model using the same composite data was completed
using the OK option in Surpac. The outcome confirmed the original model. A
check Multiple Indicator Kriging model (in the GS3M software) was completed
using the same composite data. Again the outcome confirmed the original model.
An OK check model without the JACRO composite data yielded very similar
outcomes to the original Measured and Indicated Resources.
· Block dimensions are 5m by 10m by 5m (Local E, N, RL
respectively) with no sub-blocking. The north dimension was chosen as it is
around half to a third of the nominal drillhole distances in the detailed
drilled area of the South Pit. The east dimension was chosen to take into
account the geometry and thickness of the mineralisation in the South Pit. The
vertical dimension was chosen to reflect the sample spacing and possible
mining bench heights and to allow for flexibility in potential mining
scenarios.
· Two search domains were employed, one for the South Pit (domain
1) and another for the North Pit (domain 2) respectively, reflecting a modest
change in strike between the two zones.
· All elements were modelled as a combined dataset. 5 search passes
were employed with progressively larger radii or decreasing data point
criteria. The Pass 1 used radii of 35m by 35m by 5m (along strike, down dip
and across mineralisation respectively), Passes 2, 3 and 4 used 50m by 50m by
10m, 70m by 70m by 10m & 100m by 100m by 20m respectively, Minimum number
of data was 12, maximum number of data was 32 with a minimum of 4 octants. A
fifth pass used 100m by 100m by 20m with a minimum of 6 data points from at
least 2 octants.
· The maximum extrapolation for the Mineral Resources was in the
order of 100m down dip and 100m along strike to the NE.
· The resource estimates are controlled by the data point
distribution, the variography, block size and the search ellipse. Conventional
use of wireframes to control the mineralisation was not considered necessary.
A preliminary resource model had been completed prior to the 2022/3 drilling
to ascertain likely dilution grades for peripheral material to the main tin
mineralisation with the subsequent infill drilling results generally matching
this preliminary model.
· The new block model was reviewed visually by H&SC and it was
concluded that the block model fairly represents the grades observed in the
drill holes. H&SC also validated the block model using a variety of
summary statistics and statistical plots. No issues were noted.
· Comparison with the 2013 resource estimates indicated a larger
tonnage for the 2023 Mineral Resource at approximately the same tin grade. The
main increase in tonnage was for the South Pit due to the modelling method
extrapolating much further than the rather tight wireframes that were used
previously to constrain the mineralisation. The increase is also mainly the
result of the additional exploratory TMPL drilling to the south west. Also
greater confidence in the Newmont drilling data has been achieved with the
twin holes and the repeat adit sampling to allow for Measured Resource to be
categorised.
Moisture · Whether the tonnages are estimated on a dry basis or with natural · Tonnages of the Mineral Resources are estimated on a dry weight
moisture, and the method of determination of the moisture content. basis.
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters · The resources are reported at a tin cut-off of 0.05% based on the
applied. outcome of a recently completed throughput study by independent mining
consultants AMDAD of Brisbane.
· The cut-off grade at which the resource is quoted reflects the
intended bulk-mining approach.
Mining factors or assumptions · Assumptions made regarding possible mining methods, minimum mining · The Mineral Resources were estimated on the assumption that the
dimensions and internal (or, if applicable, external) mining dilution. It is material is to be mined by open pit using a bulk mining method.
always necessary as part of the process of determining reasonable prospects
for eventual economic extraction to consider potential mining methods, but the · The proposed mining method is a conventional drill & blast,
assumptions made regarding mining methods and parameters when estimating truck & excavator with extracted material sent to an on-site ROM pad with
Mineral Resources may not always be rigorous. Where this is the case, this a processing plant adjacent to the planned pit.
should be reported with an explanation of the basis of the mining assumptions
made. · Minimum mining dimensions are envisioned to be around 10m by 5m
by 5m (strike, across strike, vertical respectively). The block size is
relatively larger than the likely minimum mining dimensions.
· The resource estimation includes internal mining dilution.
Metallurgical factors or assumptions · The basis for assumptions or predictions regarding metallurgical · Industry standard processing is envisaged for the deposit.
amenability. It is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider potential · A processing flowsheet has been proposed that will involve
metallurgical methods, but the assumptions regarding metallurgical treatment comminution, gravity separation and floatation to generate a tin concentrate.
processes and parameters made when reporting Mineral Resources may not always
be rigorous. Where this is the case, this should be reported with an · The hardness of ore material is at a manageable level.
explanation of the basis of the metallurgical assumptions made.
· Initial testwork has demonstrated that penalty elements can be
limited to acceptable levels.
· Waste products from processing can suitably be dealt with.
Environmen-tal factors or assumptions · Assumptions made regarding possible waste and process residue · The deposit lies within hilly, open country typical of the NSW
disposal options. It is always necessary as part of the process of determining Northern Tablelands.
reasonable prospects for eventual economic extraction to consider the
potential environmental impacts of the mining and processing operation. While · Land use is predominantly cattle grazing on native or improved
at this stage the determination of potential environmental impacts, pasture.
particularly for a greenfields project, may not always be well advanced, the
status of early consideration of these potential environmental impacts should · There are limited flat areas for waste and tailings disposal.
be reported. Where these aspects have not been considered this should be Most likely sites are north of a ridge line just north of the proposed pits.
reported with an explanation of the environmental assumptions made.
· Thera are a small number of creeks with seasonal flows.
· The host rocks have relatively low sulphur contents.
· Some of the mined material has acid neutralising capacity.
· Baseline data collection of a variety of environmental parameters
is in progress e.g. biodiversity, surface water and groundwater.
Bulk density · Whether assumed or determined. If assumed, the basis for the · Original bulk density measuring work completed by Newmont used single
assumptions. If determined, the method used, whether wet or dry, the frequency pieces of core subjected to the weight in air/weight in water method
of the measurements, the nature, size and representativeness of the samples. (Archimedes Principle). The result was a set of default densities: 2.8t/m(3)
for 'ore' (>0.1%Sn) and 2.7t/m(3) for waste.
· The bulk density for bulk material must have been measured by methods
that adequately account for void spaces (vugs, porosity, etc), moisture and · The 2013 Mining One estimate used a global default of 2.75t/m(3).
differences between rock and alteration zones within the deposit.
· Work completed by TMPL used a weight in air/weight in water procedure
· Discuss assumptions for bulk density estimates used in the evaluation on 415 samples of diamond core. The average value was 2.75t/m(3).
process of the different materials.
· Core inspection indicated very competent core with no significant
vughs.
· H&SC subdivided the samples using the base of oxidation surface
to ascertain the impact of surface weathering on the density. The impact was
marginal with slightly lower values in the oxidized zone as would be expected.
Default values were inserted into the block model for oxide and fresh rock
that had interpolated grades for the North Pit, and the Hillside and Payback
subdivisions of the South Pit.
· A density of 2.65t/m(3) was applied to all 'waste' i.e. blocks with
no interpolated tin grade.
Classification · The basis for the classification of the Mineral Resources into · The classification of the resource estimates is based on the data
varying confidence categories. point distribution which is a function of the drillhole spacing.
· Whether appropriate account has been taken of all relevant factors · A defined shape was used for the Measured Resource in the North
(ie relative confidence in tonnage/grade estimations, reliability of input Pit in order to remove a 'spotted dog' effect.
data, confidence in continuity of geology and metal values, quality, quantity
and distribution of the data). · Other aspects have been considered in the classification
including, the style of mineralisation, the geological model, validation of
· Whether the result appropriately reflects the Competent Person's view the historic drilling, sampling methods and recoveries, non-sampled zones, the
of the deposit. QAQC programme and results and comparison with previous resource estimates.
· H&SC believes the confidence in tonnage and grade estimates,
the continuity of geology and grade, and the distribution of the data reflect
Measured, Indicated and Inferred categorisation. The estimates appropriately
reflect the Competent Person's view of the deposit. H&SC has assessed the
reliability of the input data and takes responsibility for the accuracy and
reliability of the data used to estimate the Mineral Resources.
Audits or reviews · The results of any audits or reviews of Mineral Resource estimates. · No audits or reviews have been completed.
Discussion of relative accuracy/ confidence · Where appropriate a statement of the relative accuracy and confidence · No statistical or geostatistical procedures were used to quantify
level in the Mineral Resource estimate using an approach or procedure deemed the relative accuracy of the resource. The global Mineral Resource estimates
appropriate by the Competent Person. For example, the application of of the Taronga deposit are moderately sensitive to higher cut-off grades but
statistical or geostatistical procedures to quantify the relative accuracy of does not vary significantly at lower cut-offs.
the resource within stated confidence limits, or, if such an approach is not
deemed appropriate, a qualitative discussion of the factors that could affect · The relative accuracy and confidence level in the Mineral
the relative accuracy and confidence of the estimate. Resource estimates are considered to be in line with the generally accepted
accuracy and confidence of the nominated Mineral Resource categories. This has
· The statement should specify whether it relates to global or local been determined on a qualitative, rather than quantitative, basis, and is
estimates, and, if local, state the relevant tonnages, which should be based on the Competent Person's experience with similar deposits and geology.
relevant to technical and economic evaluation. Documentation should include
assumptions made and the procedures used. · The Mineral Resource estimates are considered to be accurate
globally, but there is some uncertainty in the local estimates due to the
· These statements of relative accuracy and confidence of the estimate current drillhole spacing, a lack of geological definition in certain places
should be compared with production data, where available. eg fault zones and penetration depths of surface weathering,
· No mining of the deposit has taken place, so no production data
is available for comparison.
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