REG - Corcel PLC - Wowo Gap JORC Resource
17/05/2022 07:00
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RNS Number : 6895L Corcel PLC 17 May 2022
/
Corcel PLC
("Corcel" or the "Company")
Wowo Gap JORC Resource
17 May 2022
Corcel, the natural resource exploration and development company with
interests in battery metals and flexible energy generation and storage, is
pleased to announce the completion of a JORC mineral resource estimate at the
Company's recently acquired Wowo Gap nickel/cobalt project in Papua New Guinea
("PNG"), where the Company owns a 100% interest. The establishment of a JORC
resource is a critical technical step in preparing the mining lease
application, validates Corcel's underlying rationale for the asset acquisition
and confirms Wo Wo Gap as a similar size and grade deposit to the Company's
sister project at Mambare, also in PNG.
Highlights:
o JORC 2012 code mineral resource estimate ("MRE") of 110m tonnes with 0.81%
Ni and 0.06% Co (891,000t contained Ni and 66,000t contained Co)
o Mineralisation is continuous and laterally extensive - shallow nature of
deposit and limited overburden is amenable to low-cost open pit mining
o Robust geological model with mineralisation well constrained within the
host saprolite and limonite layers
o Tonnage and grade reported above the 0.7% Ni cut-off compare favourably
with similar projects that have achieved production
Mineral Resource Estimate:
Using a 0.7% nickel cut-off grade, the deposit is estimated to contain 110
million tonnes at 0.81% nickel (Ni) for 891,000 tonnes of contained Ni and
0.06% cobalt (Co) for 66,000 tonnes of contained Co. Tonnage is quoted on a
dry basis.
Table 1. Wowo Gap Mineral Resource estimate by lithology type and
classification at 0.7% Ni cut-off.
Lithology Type Classification Million Tonnes Ni% Co% Thousand Tonnes contained Ni Thousand Tonnes Contained Co
Limonite/Saprolite Indicated 63 0.85 0.08 540 50
Inferred 9 0.84 0.07 76 6.3
Rocky Saprolite Inferred 38 0.75 0.02 280 7.6
Total Indicated 63 0.85 0.08 540 44
Inferred 47 0.77 0.03 360 14
Total 110 0.81 0.06 890 66
*The project operator is Niugini Nickel Ltd.
** The Company's interest in Wowo Gap is 100% and consequently Gross and Net
resource to the Company are the same
Niugini Nickel commissioned independent consulting geologists Queen and
Associates and H&S Consultants Pty Ltd (HSC) as Competent Persons to
complete a resource estimate for the Wowo Gap nickel laterite deposit
incorporating 2015 drilling and Ground Penetrating Radar (GPR) data that were
not used in the previous resource estimate.
The Competent Persons deem that there are reasonable prospects for eventual
economic extraction of the mineralisation.
Property Description and Access:
The project is located within EL 1165, approximately 200 kilometres east of
Port Moresby and 35 kilometres from the village of Wanigela, situated on
Collingwood Bay (Figure 1).
http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf
(http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf)
There is no road access to site, with personnel and equipment transported to
site by either helicopter, or by plane to a local village airstrip, followed
by a day's walk to site by locally hired porters. The small village of Embessa
is located approximately 10 kilometres northwest from site on the Musa River
and serviced by an airstrip suitable for light aircraft. Fuel, supplies and
equipment can be ferried direct to the site or from Embessa by helicopter
transport with up to 5,000 kg payload capacity. If development proceeds, it is
contemplated to construct an ore haul road directly to Collingwood Bay, some
40 km to the east.
Prospect Geology:
The Wowo Gap nickel laterite is a result of deep weathering of ultramafic
rocks of the Papuan Ultramafic Belt (PUB). In the Didana Range (Low and High)
the ultramafic rocks consist of tectonite ultramafics, cumulate ultramafics
and gabbro and granular gabbro (Figure 2).
http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf
(http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf) The
tectonite ultramafics crop out at the eastern end of the Didana Range adjacent
to and within the western section of the Wowo Gap Project. The Sivai Breccia,
co-host of the Wowo Gap mineralisation, flanks the tectonite ultramafic at the
eastern end of the Didana Range adjacent to the Bereruma Fault. The ultramafic
breccia also occurs along the south side of the Didana Range on the Ansuna and
Boge Plateau.
The nickel laterites are derived from the leaching of ultramafic bedrock. In
the project area the complete lateritic profile is preserved, with partial
truncation associated with recent drainage systems. The depth of weathering
varies according to rock type and the degree of brecciation. The lateritic
profile is typically 10 to 15 metres thick, increasing locally to more than 30
metres above the Sivai Breccia.
The laterite profile (Figure 3)
http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf
(http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf) is
typically 10m to 18m thick and composed of an upper iron-rich saprolite
horizon (referred to as limonite) with high (>40%) to very high (>60%)
Fe2O3 content but relatively low (<6%) MgO. It is the limonite horizon that
contains enriched levels of cobalt, chromium and manganese values. Beneath the
limonite is MgO-rich (>6 - 40%) earthy saprolite (referred to as saprolite)
horizon with relatively low (<40%) Fe2O3 content. Below this in the
regolith profile is the rocky saprolite (saprock), clearly identifiable
because of corestones of partially weathered ultramafic bedrock.
Project History:
Nickel laterite mineralisation in the Didana Range was first noted in a 1958
Australian Bureau of Mineral Resources (BMR) reconnaissance survey of the area
including Wowo Gap. Nickel mineralisation was reported in auger samples of
breccia which returned values of up to 1.3% Ni, derived from a peridotite
ultramafic having up to 0.18% Ni background values. This initial discovery was
followed by several companies including United States Metals Refining Company
(1967-1968), Papua Nickel Exploration (1970) and BRGM (1971-1972). The current
period of exploration started when Niugini Nickel acquired the project in
1996. Since acquiring the project Niugini Nickel has carried out considerable
work including geological mapping, resampling of pits, rock chip sampling,
drainage sampling, several drilling programmes, a LiDAR survey over the whole
of the mineralized area, two Ground Penetrating Radar (GPR) surveys (2007 and
2014), metallurgical test work and several Resource estimates.
This Mineral Resource estimate is based on the results of three drilling
campaigns:
o diamond core drilling 2003-2008
o tungsten carbide-tipped core drilling 2010-2011 , and
o diamond core and custom auger core drilling 2014-2015 .
These drilling campaigns totalled 3,174 meters of diamond core, 2,901 meters
of auger/carbide core, and 731 meters of wacker drilling (Figures 4, 5, and
6). Sample lengths were generally 1m with the shortest sample being 0.3m and
the longest 2m; sampling was done on half core. All drill core samples were
sent to Intertek in Lae for sample preparation, with the pulps being sent to
Intertek Jakarta for fusion XRF analysis for Ni, Co, Al2O3, CaO, Cr2O3, Fe2O3,
K2O, LOI, MgO, MnO, Na2O, P2O5, SiO2 and LOI. Total number of samples assayed
was 7874.
This Mineral Resource estimate is also based on two GPR surveys (2007 and
2014). In addition to the drilling data, GPR was used to define two of the
geological boundaries, the boundary between limonite/saprolite and the rocky
saprolite and the boundary between rocky saprolite and bedrock (Figure
7) http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf
(http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf) The GPR
lines in 2007 were between 200 and 300 metres apart while the 2014 survey
reduced the spacing to 100 metres over a portion of the area (Figure
8) http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf
(http://www.rns-pdf.londonstockexchange.com/rns/6895L_1-2022-5-16.pdf)
For grade estimation the laterite layers were simplified into overburden
(Qva), limonite/non rocky saprolite and rocky saprolite which in turn were
used to guide and control the mineral resource estimate. Samples from each
hole were used and were composited to the full width of the layer, making one
composite per layer for each of the three layer; the mineralised domains were
limited to the three interpreted geological layers as noted above. Nickel and
cobalt grades from the composites where estimated using the ordinary kriging
(OK) estimation technique in Micromine software. The mineralised domains were
limited to the three interpreted geological layers as noted above. The grade
distributions for nickel and cobalt are not strongly skewed so OK was an
appropriate estimation method; there are no extreme values requiring grade
cutting.
Resource classification is based on both the overall footprint of the GPR
coverage and drilling. A polygon covering the area with nominal 300 m x 200 m
drill spacing along with the GPR coverage was used to flag the block model as
follows:
o any Qva or limonite-saprolite blocks within it are classified as
Indicated,
o rocky saprolite blocks are classified as Inferred regardless of the
polygon, and
o any blocks outside of classification polygon are classified as Inferred.
Density is based on the results of a limited number of samples collected
during the 2010-2011 and 2014-2015 drilling campaigns. Based on this data a
dry bulk density of 1.0 t/m3 has been used for the "clay profile"
(limonite-saprolite layer), and 2.0 t/m3 for the rocky saprolite profile.
A nominal cut-off grade of 0.70% Ni was applied to define the Mineral
Resources, which is based on a review of comparable nickel laterite deposits
elsewhere.
The current mining plan proposal is to produce a bulk product suitable for
smelting that will be transported offsite for processing. It has been assumed
that mine waste will be relatively low in total volume and comprise the 0.5 m
to 10 m soil and volcanic ash overburden layer. This material is likely to be
used for rehabilitation purposes after mining is complete. Low-grade material,
mostly limonitic in composition, may be stockpiled in mined-out areas.
Reasonable Prospects Hurdle:
Clause 20 of the JORC Code (2012) requires that all reports of Mineral
Resources must have reasonable prospects for eventual economic extraction,
regardless of the classification of the Mineral Resource. The Competent
Persons deem there are reasonable prospects for eventual economic extraction
of the mineralisation on the following basis:
o The mineralisation is continuous and laterally extensive. The shallow
nature of the deposit and limited overburden means the deposit is amenable to
low-cost open pit mining.
o The geological model is robust, with mineralisation well constrained
within the host saprolite and limonite layers.
o The Competent Person considers that the tonnage and grade reported above
the 0.7% Ni cut-off compare favourably with similar projects that have
successfully achieved production. This opinion is based on experience with
tropical nickel laterite deposits in Papua New Guinea at all stages of project
development.
Comparison to Previous Resource:
In 2011 Resource Mining Corporation (ASX:RMI) released a Mineral Resource
estimate for the Wowo Gap deposit (https://tinyurl.com/yc6zwjbw
(https://tinyurl.com/yc6zwjbw) ).
Table 2. Wowo Gap 2011 Mineral Resource estimate by classification at 0.8% Ni
cut-off.
2011 Mineral Resource Estimate at a 0.8% Ni cut-off Mt Nickel (%) Cobalt (%)
Indicated 72 1.03 0.07
Inferred 53 1.09 0.06
Total 125 1.06 0.07
Contained Metal (kt) 1,325 83
The Mineral Resource estimate in this release has a number of differences from
the 2011 Mineral Resource that have resulted in changes to the estimated
grades and tonnages. The most significant of those changes include:
o Trimming of margins- The 2011 estimate was reported using a very wide
margin (300 m) on the edge of the drilling area. This resulted in holes on the
edge of the drilling having more influence than holes in the centre of the
drilling. The 2022 model, in keeping with industry best practice, trims this
margin to 150 m or roughly half the average hole spacing. As there are several
higher grade and thickness holes on the eastern edge of the drilling,
restricting the margin has resulted in a reduction of both tonnes and grade.
o Better definition of the overburden/volcanic ash- The previous estimate
identified the overburden/volcanic ash solely based on the drill hole logs.
The 2015 drilling gave us confidence we could use geochemical criteria (high
Al2O3 and lower Ni grade) to objectively define the overburden. The overburden
in the 2022 model is more widespread and is less poddy than in the previous
model. This has contributed to the reduction in tonnage but has minimal impact
on grade.
o Regression to the mean- The 2015 GPR and drilling program focused on an
area with higher grades and thickness. As more drill sampling and GPR data was
collected in the area, this area dropped back toward the mean of the deposit.
The area is still "higher" grade but the drilling and GPR have reduced the
extent and the degree to which it departs from the mean grade and thickness.
o Reporting at a lower cut-off grade- The previous cut-off grade of 0.8% was
based on historic processing and mining assumptions that emphasized the rocky
saprolite portion of the Resource over the non-rocky limonite and saprolite
layers. Lowering the cut-off grade will impose few assumptions on the Resource
and will allow the mining engineers greater flexibility when it comes to
developing a mine plan and a Reserve estimate.
For detail of exploration drilling results, see the following Resource Mining
Corporation Ltd (ASX:RMI) announcements:
o 8 December 2010. Wowo Gap Project Exploration Program Highlights
o 3 February 2011. Wowo Gap Project Exploration Program Highlights
o 23 June 2011. Wowo Gap Project Exploration Program Highlights
o 30 August 2011. Wowo Gap Project Exploration Program Highlights
o 4 March 2015. Exploration Update: Wowo Gap Nickel Laterite Project
o 18 March 2015. Exploration Update: Wowo Gap Nickel Laterite Project
o 29 April 2015. Wowo Gap exploration intersects high grade Nickel up to 1m
@ 3.51%Ni
o 21 May 2015. Wowo Gap exploration intersects high grade Nickel up to 3m @
1.87%Ni
Competent Persons and Qualified Persons Statement:
The information in this report that relates to Mineral Resources is based on
information compiled by Lawrence Queen and Luke Burlet. Lawrence Queen is an
employee of Queen and Associates, and Luke Burlet is employed by H&S
Consultants. Mr Queen is a Member of the Australasian Institute of Mining and
Metallurgy, and Mr Burlet is a Member of the Australian Institute of
Geoscientists. Mr Queen and Mr Burlet have sufficient experience relevant to
the style of mineralisation and type of deposit under consideration and to the
activity which they are is undertaking to qualify as Competent Persons as
defined in the 2012 Edition of the Australasian Code for the Reporting of
Exploration Results, Mineral Resources and Ore Reserves (JORC Code) and have
sufficient relevant experience to qualify as a qualified person as defined in
the Guidance Note for Mining, Oil and Gas Companies as published by AIM. Mr
Queen and Mr Burlet have reviewed the information in this announcement and
consent to the disclosure of the information in this report in the form and
context in which it appears.
For further information, please contact:
Scott Kaintz 020 7747 9960
Corcel Plc CEO
James Joyce / Andrew de Andrade 0207 220 1666
WH Ireland Ltd NOMAD & Broker
Simon Woods 0207 3900
230
Vigo Communications IR
The information contained within this announcement is deemed to constitute
inside information as stipulated under the retained EU law version of the
Market Abuse Regulation (EU) No. 596/2014 (the “UK MAR”) which is part of
UK law by virtue of the European Union (Withdrawal) Act 2018. The information
is disclosed in accordance with the Company’s obligations under Article 17
of the UK MAR. Upon the publication of this announcement, this inside
information is now considered to be in the public domain.
Glossary of Technical Terms:
"auger drill" a type of drill which uses a corkscrew type bit to recover
samples from unconsolidated materials;
"block model" Refers to the process of creating a 3D spatial array of
estimations. The parameter that is being estimated may be the thickness of the
ore, the grade of the ore, or some other property that is useful for the
evaluation of the resource. These estimations are based on a weighted average
of the values associated with the surrounding control points. A variety of
interpolation methods or "algorithms" are available for performing these
estimations. A popular technique is ordinary Kriging;
"bulk density" is the mass per unit volume of a solid, including the voids in
a bulk sample of the material;
"Co" cobalt;
"Competent Person" a 'Competent Person' is a minerals industry professional
who is a Member or Fellow of The Australasian Institute of Mining and
Metallurgy, or of the Australian Institute of Geoscientists, or of a
'Recognised Professional Organisation' (RPO), as included in a list available
on the JORC and ASX websites. These organisations have enforceable
disciplinary processes including the powers to suspend or expel a members;
"core recovery" amount of rock recovered when diamond core drilling usually
expressed as a percentage;
"cut-off grade" a grade level below which the material is not of economic
interest and considered to be uneconomical to mine and process. The minimum
grade of mineralisation used to establish reserves;
"development" often refers to the construction of a new mine or; Is the
underground work carried out for the purpose of reaching and opening up a
mineral deposit includes shaft sinking, cross-cutting, drifting and raising;
"diamond drillhole" a drillhole which is drilled used a diamond impregnated
bit so that a cylindrical sample of solid rock (drill core) can be recovered;
"Ground Penetrating Radar" a geophysical method that uses radar pulses to
image the subsurface;
"Indicated Resource" that part of a Mineral Resource for which quantity,
grade or quality, densities, shape and physical characteristics, can be
estimated with a level of confidence sufficient to allow the appropriate
application of technical and economic parameters, to support mine planning and
evaluation of the economic viability of the deposit. The estimate is based on
detailed and reliable exploration and testing information gathered through
appropriate techniques from locations such as outcrops, trenches, pits,
workings and drill holes that are spaced closely enough for geological and
grade continuity to be reasonably assumed;
"Inferred Resource" that part of a Mineral Resource for which quantity and
grade or quality can be estimated on the basis of geological evidence and
limited sampling and reasonably assumed, but not verified, geological and
grade continuity. The estimate is based on limited information and sampling
gathered through appropriate techniques from locations such as outcrops,
trenches, pits, workings and drill holes;
"JORC" the Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves, as published by the Joint Ore Reserves Committee
of The Australasian Institute of Mining and Metallurgy, Australian Institute
of Geoscientists and Minerals Council of Australia;
"JORC (2012)" the 2012 edition of the JORC code;
"laterite" a laterite is a residual soil rich in iron and aluminum hydroxides
which develops in a humid tropical climate. Where these soils are enriched
in nickel they are referred to as a nickel laterite;
"lithology" the lithology of a rock unit is a description of its physical
characteristics visible at outcrop, in hand or core samples or with low
magnification microscopy, such as colour, texture, grain size, or composition;
"m" metre;
"Mineral Resource" a concentration or occurrence of material of economic
interest in or on the earth's crust in such form and quantity that there are
reasonable and realistic prospects for eventual economic extraction. The
location, quantity, grade, continuity, and other geological characteristics of
a Mineral Resource are known, estimated from specific geological evidence and
knowledge, or interpreted from a well-constrained and portrayed geological
model;
"Ni" nickel;
"open pit" a mine that is entirely on the surface. Also referred to as
open-cut or opencast mine;
"overburden" material of any nature, consolidated or unconsolidated, that
overlies a deposit of ore that is to be mined;
"oxidation" a chemical reaction in which substances combine with oxygen for
form an oxide. For example, the combination of iron with oxygen to form an
iron oxide (rust) or copper and oxygen produce copper oxide; the green coating
on old pennies. The opposite of oxidation is reduction.
"QAQC" Quality assurance and Quality control of the geological sample
database;
"Reverse Circulation- RC drilling" A percussion drilling technique that
produces chip samples that are removed from the drillhole by compressed air
pushing the sample up the inside of the drill rods. Considered superior to
aircore drilling; generating better quality samples
"strike length" the horizontal distance along the long axis of a structural
surface, rock unit, mineral deposit or geochemical anomaly;
"t" tonnes;
"variogram" a function of the distance and direction separating two locations
that is used to quantify dependence. The variogram is defined as the variance
of the difference between two variables at two locations. The variogram
generally increases with distance and is described by nugget, sill, and range
parameters. If the data is stationary, then the variogram and the covariance
are theoretically related to each other.
"variogram model" a model that is the sum of two or more component models,
such as nugget, spherical, etc. Adding a nugget component to one of the other
models is the most common nested model, but more complex combinations are
occasionally used;
"wacker" a semi-mechanised deep overburden soil sampling method commonly used
in PNG;
"weathering" disintegration or alteration of rock in its natural or original
position at or near the Earth's surface through physical, chemical, and
biological processes induced or modified by wind, water, and climate.
JORC Code, 2012 Edition - Table 1 report
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 · All the samples used in this Mineral Resource Estimate are from
specific specialised industry standard measurement tools appropriate to the drill core. The core was obtained over three main drill campaigns.
minerals under investigation, such as down hole gamma sondes, or handheld XRF
instruments, etc). These examples should not be taken as limiting the broad o Wacker drilling - 153 holes totaling 731 m. 3 cm diameter core- (nominal
meaning of sampling. AQ). Only tested the non-rocky laterite.
· Include reference to measures taken to ensure sample representivity o Diamond core- (2003-2008 and 2014-201 5)161 holes totaling 3174.2 m. HQ or
and the appropriate calibration of any measurement tools or systems used. NQ core.
· Aspects of the determination of mineralisation that are Material to o Tungsten carbide coring (2010-2011)- 297 holes totaling 1745.8 m. Only
the Public Report. tested the non-rocky laterite.
· In cases where 'industry standard' work has been done this would be o Auger core (2014-2015)- 125 holes totaling 944.5 m. Only tested the
relatively simple (eg 'reverse circulation drilling was used to obtain 1 m non-rocky laterite.
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 · The drill methods were chosen to provide a sample of the friable
is coarse gold that has inherent sampling problems. Unusual commodities or laterite that was relatively undisturbed.
mineralisation types (eg submarine nodules) may warrant disclosure of detailed
information.
Drilling techniques · Drill type (eg core, reverse circulation, open-hole hammer, rotary · This Mineral Resource Estimate is based on results diamond core
air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or drilling (2003 - 2008), tungsten carbide-tipped core drilling (2010-2011), and
standard tube, depth of diamond tails, face-sampling bit or other type, (2014-2015) diamond core and custom auger core drilling. All holes are
whether core is oriented and if so, by what method, etc). vertical.
Drill sample recovery · Method of recording and assessing core and chip sample recoveries and · As the core is recovered from the triple tube (NQ3), core
results assessed. recoveries are typically very good. The recoveries were logged and recorded in
the database.
· Measures taken to maximise sample recovery and ensure representative
nature of the samples. · Core is recovered from the triple tube (NQ3) drilling to ensure
good recovery.
· Whether a relationship exists between sample recovery and grade and
whether sample bias may have occurred due to preferential loss/gain of · Overall recoveries are>90% and there are no significant sample
fine/coarse material. recovery problems.
Logging · Whether core and chip samples have been geologically and · Logging of the core recorded lithology, mineralogy, weathering,
geotechnically logged to a level of detail to support appropriate Mineral colour and other features of the samples. The core from each core run were
Resource estimation, mining studies and metallurgical studies. placed in plastic core trays for logging and photographed, then sampled.
· Whether logging is qualitative or quantitative in nature. Core (or Geotechnical logging was not conducted for mineralization purposes as there is
costean, channel, etc) photography. no structural control to the mineralization.
· The total length and percentage of the relevant intersections logged. · The logging is both qualitative and quantitative in nature
including records of lithology, (ore layer type), mineralogy, textures,
oxidation state and colour. Visual estimates of percentages of key minerals
associated with nickel mineralization and their appearance and percent volume
of rock in diamond core samples of the rocky saprolite. All core was
photographed. 31 pits were also dug and sampled as supporting evidence but not
used in the Resource estimation.
· All holes drilled were logged.
Sub-sampling techniques and sample preparation · If core, whether cut or sawn and whether quarter, half or all core · Core samples were collected from half core, on typical 1 metre
taken. lengths through the laterite profile.
· If non-core, whether riffled, tube sampled, rotary split, etc and · No non-core samples were taken.
whether sampled wet or dry.
· The samples were submitted to Intertek Laboratory in Lae, Papua
· For all sample types, the nature, quality, and appropriateness of the New Guinea (PNG) for preparation. All samples received were weighed and wet
sample preparation technique. weight recorded, then dried at 105°C for at least 16 hours. Samples were then
crushed with 95% passing -2 mm. Crushed samples were then riffle split, with a
· Quality control procedures adopted for all sub-sampling stages to split taken for fine pulverising to 95% passing -200 μm, with the remainder
maximise representivity of samples. retained as coarse residue. For samples of less than 1.5 kg, no coarse residue
was retained. The pulverised (pulp) samples were forwarded to Intertek
· Measures taken to ensure that the sampling is representative of the Laboratory in Jakarta, Indonesia for assay of Ni, Co, Al(2)O(3), CaO,
in situ material collected, including for instance results for field Cr(2)O(3), Fe(2)O(3), K(2)O, LOI, MgO, MnO, Na(2)O, P(2)O(5), SiO(2) and LOI
duplicate/second-half sampling. by fusion XRF. The sample preparation technique is considered
· Whether sample sizes are appropriate to the grain size of the appropriate for the style of mineralisation under consideration.
material being sampled.
· Certified reference materials were used at a rate of 1 standard
per 20 samples and a field duplicate is collected from the unsampled half core
for every second hole.
· The bulk of the laterite is made of silt to clay size particle so
sample size is appropriate for the granularity of the sampled target mineral.
Quality of assay data and laboratory tests · The nature, quality and appropriateness of the assaying and · The core samples were sent to Intertek in Lae for sample
laboratory procedures used and whether the technique is considered partial or preparation, with the pulps being sent to Intertek Jakarta for fusion XRF
total. analysis for Ni, Co, Al(2)O(3), CaO, Cr(2)O(3), Fe(2)O(3), K(2)O, LOI, MgO,
MnO, Na(2)O, P(2)O(5), SiO(2) and LOI. This method is considered a total
· For geophysical tools, spectrometers, handheld XRF instruments, etc, assay.
the parameters used in determining the analysis including instrument make and
model, reading times, calibrations factors applied and their derivation, etc. · No portable XRF machines were used to determine any element
concentrations used in the grade determinations.
· Nature of quality control procedures adopted (eg standards, blanks,
duplicates, external laboratory checks) and whether acceptable levels of · Sample preparation checks for fineness were carried out by the
accuracy (ie lack of bias) and precision have been established. laboratory as part of their internal procedures to ensure the grind size of
85% passing 75 micron was being attained.
· Laboratory QAQC involves the use of internal lab standards using
certified reference material, blanks, splits, and replicates as part of the
in-house procedures.
· Certified reference materials were used in the 2014-2015 drilling
program, with a certified standard added to every second hole.
· Field duplicate samples were submitted from alternate holes.
Verification of sampling and assaying · The verification of significant intersections by either independent · No verification was carried out.
or alternative company personnel.
· In 2010 - 2011, a second twin hole was drilled within one metre
· The use of twinned holes. of the original hole for every fourth or fifth hole drilled. These samples
were sent to Ultratrace Laboratories for fusion XRF analysis. Comparison of
· Documentation of primary data, data entry procedures, data the twin hole data was used to estimate short range variance (0.52).
verification, data storage (physical and electronic) protocols.
· Logging data was collected using a set of standard paper logging
· Discuss any adjustment to assay data. sheets which were entered into Maxwell's Logchief logging software.
· The information was sent to Mr M Hill in the Perth office for
validation and forwarded to Maxwell's for importing into the Datashed
Database.
· There was no adjustment to any assay data.
Location of data points · Accuracy and quality of surveys used to locate drill holes (collar · Diamond holes from both the 2003 - 2004 and 2007 drilling
and down-hole surveys), trenches, mine workings and other locations used in programs were surveyed by Arman Larmer Surveys Ltd Consulting Surveyors (PNG)
Mineral Resource estimation. using a Wild 805 Total Station, traversing from survey control stations which
were located using an Omnistar DGPS with a reported accuracy of +/- 0.1
· Specification of the grid system used. metres.
· Quality and adequacy of topographic control. Drill holes in 2008, 2010, 2011 and 2014 were surveyed by a handheld GPS.
Horizontal accuracy is estimated to be +/- 5 meters.
· All spatial data is recorded in AMG84, zone 55
· Topographic control is based on a digital elevation model derived
from a LiDAR survey flown by Digital Mapping Australia Pty Ltd (DiMap) in
April 2007.
Data spacing and distribution · Data spacing for reporting of Exploration Results. · Nominal drilling spacing for most of the area is 300 metres x 200
metres.
· Whether the data spacing and distribution is sufficient to establish
the degree of geological and grade continuity appropriate for the Mineral For the areas covered by the 2014-2015 drilling the nominal drill hole spacing
Resource and Ore Reserve estimation procedure(s) and classifications applied. is 200 metres on 100 metres spaced east - west lines.
· Whether sample compositing has been applied. · Each of the laterite layers shows low variability and long range
(100s of metres) continuity of the economically important elements (Ni &
Co). The data spacing and distribution is sufficient to demonstrate spatial
and grade continuity of the mineralized horizons to support the definition of
Inferred/Indicated Mineral Resources under the 2012 JORC code
· Samples were composited based on mineralization type
(Overburden/Volcanic Ash, Limonite, non-rocky Saprolite, and Rocky Saprolite)
Orientation of data in relation to geological structure · Whether the orientation of sampling achieves unbiased sampling of · Lateritic nickel mineralisation develops broadly parallel to the
possible structures and the extent to which this is known, considering the topographic surface and vertical drilling orientation is generally unbiased.
deposit type.
· No sampling bias from drillhole orientation is expected. The
· If the relationship between the drilling orientation and the drillholes are vertical, with mineralisation generally horizontal and not
orientation of key mineralised structures is considered to have introduced a obviously related to structure.
sampling bias, this should be assessed and reported if material.
Sample security · The measures taken to ensure sample security. · Chain of custody was managed by RMC. Samples were stored on site and
delivered to an independent transport company in Port Moresby, PNG which
delivered them to the assay laboratory in Lae, PNG the following day.
Audits or reviews · The results of any audits or reviews of sampling techniques and data. · An independent due diligence study of the exploration procedures used
on the Wowo Gap nickel laterite project was carried out by Robin Rankin of
GeoRes in April 2011. This review concluded the work by Niugini Nickle was
well founded and completely applicable to good exploration of a nickel
laterite type deposit.
· In 2015 Torridon Exploration carried out an independent audit of the
2014-2015 drilling program. The review found the exploration drilling
program was appropriate for a nickel laterite deposit and conformed to
accepted industry practice.
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 Wowo Gap nickel laterite project is located near Embessa in
agreements or material issues with third parties such as joint ventures, the Oro Province of Papua New Guinea. The project is contained within EL 1165,
partnerships, overriding royalties, native title interests, historical sites, which is owned by Niugini Nickel Limited, a wholly owned subsidiary of Corcel
wilderness or national park and environmental settings. Plc, a UK company listed on the Alternative Investment Market of the London
Stock Exchange. Royalties payable on gross revenues are expected to be 1% PNG
· The security of the tenure held at the time of reporting along with government. There are no native title, historical, national park, or other
any known impediments to obtaining a licence to operate in the area. impediments.
· The tenement is currently in good standing pending renewal.
Exploration done by other parties · Acknowledgment and appraisal of exploration by other parties. · Nickel laterite mineralization in the area around Wowo Gap was first
reported by the BMR in 1958. Auger samples of breccia assayed up 1.3% Ni,
Geology · Deposit type, geological setting, and style of mineralisation. The Wowo Gap mineralization is a wet tropical nickel laterite. In the project
area an east dipping lateritic profile has developed over the underlying
ultramafics. The complete lateritic profile is preserved, with partial
truncation associated with recent drainage systems. The depth of weathering
varies according to rock type and the degree of brecciation. The lateritic
profile is typically 10 to 15 metres thick, occasionally more than 30 metres
above the Sivai Breccia.
The laterite profile is typically 10m to 18m thick and composed of an upper
iron-rich saprolite horizon (referred to as limonite) with high a (>40%) to
very high (>60%) Fe(2)O(3) content but relatively low (<6%) MgO. It is
the limonite horizon that contains enriched levels of cobalt, chromium and
manganese values. Beneath the limonite is MgO-rich (>6 - 40%) earthy
saprolite (referred to as saprolite) horizon with relatively low (<40%)
Fe(2)O(3) content. Below this in the regolith profile is the rocky saprolite
(saprock), clearly identifiable because of corestones of partially weathered
ultramafic bedrock.
Drill hole Information · A summary of all information material to the understanding of the · All the drill holes used for this Resource estimate were completed
exploration results including a tabulation of the following information for prior to the end of 2015. Details for those holes were reported in ASX
all Material drill holes: announcements that can be found on the Resource Mining Corporation website
(https://resmin.com.au/investor-centre/asx-announcements/)
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, · Only Mineral Resources are being reported. As no exploration results
maximum and/or minimum grade truncations (eg cutting of high grades) and are being reported, this section is not considered applicable.
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 · Only Mineral Resources are being reported. As no exploration results
Exploration Results. are being reported, this section is not considered applicable.
· If the geometry of the mineralisation with respect to the drill hole
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 · Only Mineral Resources are being reported. As no exploration results
intercepts should be included for any significant discovery being reported are being reported, this section is not considered applicable.
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 · Only Mineral Resources are being reported. As no exploration
practicable, representative reporting of both low and high grades and/or results are being reported, this section is not considered applicable.
widths should be practiced to avoid misleading reporting of Exploration
Results.
Other substantive exploration data · Other exploration data, if meaningful and material, should be · Only Mineral Resources are being reported. As no exploration
reported including (but not limited to): geological observations; geophysical results are being reported, this section is not considered applicable.
survey results; geochemical survey results; bulk samples - size and method of
treatment; metallurgical test results; bulk density, groundwater, geotechnical
and rock characteristics; potential deleterious or contaminating substances.
Further work · The nature and scale of planned further work (eg tests for lateral · The portion of the Mineral Resource corresponding to the area of the
extensions or depth extensions or large-scale step-out drilling). 2014 GPR cover meets many but not all of the criteria to be classified as
Measured. Some additional drilling, bulk density sampling, further QAQC work
· Diagrams clearly highlighting the areas of possible extensions, and further resource modelling subdividing the laterite into limonite and
including the main geological interpretations and future drilling areas, saprolite layers may be sufficient to allow this portion of the Resource to be
provided this information is not commercially sensitive. reclassified
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 · Logging data was collected using a set of standard paper logging
example, transcription or keying errors, between its initial collection and sheets which were entered into Maxwell's Logchief logging software.
its use for Mineral Resource estimation purposes.
· The information was sent to Mr M Hill in the Perth office for
· Data validation procedures used. validation and forwarded to Maxwell's for importing into the Datashed
Database.
· The WoWo drilling data was provided in a Microsoft Access
database. Ground Penetrating Radar (GPR) surveys (2007 and 2014) and
topographic data (LiDAR) were provided in CSV format.
· A range of basic checks were performed by H&SC prior to the
resource estimates to ensure data consistency, including, but not limited to,
checks for From-To interval errors, missing or duplicate collar surveys,
excessive down hole deviation, and extreme or unusual assay values.
· A range of drilling methods have been used at WoWo and
incorporated into the resource modelling:
Hole Type total (m) Year_min Year_max
pit 253 1971 2004
diamond drill Hole 3,174 1972 2015
wacker 731 1999 2008
auger 2,901 2010 2015
· Independent consultant Larry Queen conducted a review of the
various drilling and sample types to confirm that they are suitable to form
the basis of the Mineral Resource Estimates (MREs).
Site visits · Comment on any site visits undertaken by the Competent Person and the · No site visits have been made by the Competent Persons for this
outcome of those visits. report as until recently, access to the area has been impossible due to
COVID19 travel restrictions. However, Mr. Queen has over 30 years of
· If no site visits have been undertaken indicate why this is the case. experience in PNG and has served as Competent Person for the similar Ramu
Nickel Laterite and the Sewa Bay Nickel Laterite. Mr Queen has reviewed all
the documentation from the previous work and is confident Wowo Gap is broadly
similar to other tropical laterites in PNG.
Geological interpretation · Confidence in (or conversely, the uncertainty of ) the geological · The grade and lithological interpretation forms the basis for the
interpretation of the mineral deposit. modelling. Grades have all been estimated constrained within the lateritic
layers (rock types).
· Nature of the data used and of any assumptions made.
· Based on experience at other nickel laterites in PNG and the
· The effect, if any, of alternative interpretations on Mineral drill log and geochemical interpretation there is strong confidence in the
Resource estimation. geological interpretation of the lateritic layers (rock types) of the deposit.
The upper layers, especially the limonite layer, are usually continuous, with
· The use of geology in guiding and controlling Mineral Resource the absence of the limonite layer always due to erosion especially around the
estimation. incised streams. The grades including cobalt, are usually continuous and show
little lateral variability.
· The factors affecting continuity both of grade and geology.
· Core recording, sample analysis and ground penetrating radar
(GPR) were applied to interpret the geological domains of deposit. The
overburden/limonite boundary was created using grade composites based on
aluminium and nickel percentage. Samples with greater than 20% Al(2)O(3) were
classified limonite. GPR data was used to define of the bottom of
limonite/saprolite top of rocky saprolite.
· The Wowo Gap deposit has been the subject of several previous
resource estimates, the most recent dated December 2011
(https://resmin.com.au/wp-content/uploads/docs/asx_announcements/2011/20111214%20Wowo%20Gap%20Resource%20Upgrade.pdf
(https://resmin.com.au/wp-content/uploads/docs/asx_announcements/2011/20111214%20Wowo%20Gap%20Resource%20Upgrade.pdf)
). All the resource models have been similar (i.e. the laterite occurs as a
layer-cake like deposit that drapes over the topography.) and vary mostly in
the amount of supporting data (drill holes and GPR)
· The GPR data was used to interpret and define a bottom of
Limonite-non rocky Saprolite and a bottom of rocky Saprolite surface. In the
stream incised areas where there was little, or no GPR data low laterite
thicknesses were used as defaults. This was done as it was assumed the
laterite profile would be largely removed along the streams.
· The logged lithology and the geochemistry was also used to define the
zone of Quaternary overburden (mainly volcanic ash, "Qva"), the logged zone of
limonite-non rocky saprolite and rocky saprolite.
· The Qva zone was used to define the bottom of overburden. Thus three
geological zones/layers were defined, overburden (Qva), limonite-non rocky
saprolite and rocky saprolite which in turn were used to guide and control the
mineral resource estimate.
· The interpreted overburden/Qva thickness ranges between 0 and 10m and
averages 0.5m, the limonite-non rocky saprolite between 0 and 23m and averages
3m, and the rocky saprolite between 0 and 20m and averages 3.8m
Dimensions · The extent and variability of the Mineral Resource expressed as · The drilled laterite covers an area of 8700 metres N-S by 3300 to
length (along strike or otherwise), plan width, and depth below surface to the 4000 meters E-S. The average thickness of the laterite above the rocky
upper and lower limits of the Mineral Resource. saprolite is roughly 7 metres with maximum thickness of 19 metres
Estimation and modelling techniques · The nature and appropriateness of the estimation technique(s) applied · Nickel and cobalt grades were estimated with using the ordinary
and key assumptions, including treatment of extreme grade values, domaining, kriging (OK) estimation technique in Micromine software. Samples from each
interpolation parameters and maximum distance of extrapolation from data hole were used and composited to the full width of the layer, making 1
points. If a computer assisted estimation method was chosen include a composite per layer for each of the three layer; the mineralised domains were
description of computer software and parameters used. limited to the three interpreted geological layers as noted above. The grade
distributions for nickel and cobalt are not strongly skewed so OK was an
· The availability of check estimates, previous estimates and/or mine appropriate estimation method; there are no extreme values requiring grade
production records and whether the Mineral Resource estimate takes appropriate cutting.
account of such data.
The three layers were estimated separately, i.e., with hard boundaries.
· The assumptions made regarding recovery of by-products.
A two pass search strategy was used for OK estimation:
Search axis 1 axis 2 axis 3 max samples min total min hole
· Estimation of deleterious elements or other non-grade variables of radians (m) radians (m) radians (m) per quadrant samples count
economic significance (eg sulphur for acid mine drainage characterisation). 1 40 1000 1000 6 4 4
2 40 1200 1200 6 4 4
· In the case of block model interpolation, the block size in relation
to
· the average sample spacing and the search employed. · The block model was setup as a 'grade thickness model' where both
grade and thickness are estimated for each of the 3 layers. Due to the steep
· Any assumptions behind modelling of selective mining units. and widely undulating terrain, the block model and input grade and thickness
data from drilled was 'flattened' to a common dummy RL. This allowed a common
· Any assumptions about correlation between variables. search orientation to be used during the OK estimation routine.
· Description of how the geological interpretation was used to control · The orientation of the search ellipsoid and variogram models was
the resource estimates. isotropic in the horizontal plane of the flattened block model.
· Discussion of basis for using or not using grade cutting or capping. · The maximum extrapolation distance would be close to the maximum
search radii of 900m.
· The process of validation, the checking process used, the comparison
of model data to drill hole data, and use of reconciliation data if available. · There is a previous estimate (Ravensgate, 2011) that is broadly
compatible with the current MREs, but substantial differences in the
interpretation and modelling of mineralisation, as well as additional drilling
and more extensive and more detailed GPR technique, make detailed comparisons
to the 2011 MRE meaningless. The current MREs take appropriate account of
previous estimates, while acknowledging substantial differences in methodology
and data. H&SC also ran a non-grade thickness model, still using OK, but
with set block heights and on a block fraction basis. This block definition is
more common in gold or base metal models. The overall results of the check
model were closely comparable and gives confidence in the grade- thickness
methodology.
· The deposits remain unmined so there are no production records
for comparison.
· Only nickel and cobalt were estimated, so no potential
by-products or deleterious elements were assessed; consequently, no
assumptions are made regarding the correlation of variables.
· Dry bulk density was assigned by geological layer zone, based on
average values for available measurements quoted by Ravensgate (2011)
· The block size for the model is a constant 10x10 in Easting and
Northing with a variable block height for each of the 3 geological layers. In
this way the block model is three blocks high at each 10x10 cell. A 10x10 cell
size was chosen as this considers the steep and undulating terrain, thus
largely avoiding the need for block proportions or sub-blocking.
· The new model was validated in several ways - visual comparison
of block and drill hole grades, statistical analysis (summary statistics),
examination of grade-tonnage data, and comparison with previous estimates and
the check model.
· Average estimated grades are lower than average composite grades,
reflecting clustering in the drill hole data and slightly skewed grade
distributions.
· All the validation checks suggest that the grade estimates are
reasonable when compared to the composite grades, allowing for data
clustering.
Moisture · Whether the tonnages are estimated on a dry basis or with natural · All tonnes reported in the Mineral Resource are
moisture, and the method of determination of the moisture content.
estimated on a dry basis.
The moisture and dry bulk density were measured using a cylinder of core. The
volume of the sample was determined by measuring the length and diameter of
the sample. The wet sample is weighed first, the sample is then dried in a
drying oven under a constant temperature of 105°C, and then the dry weight is
determined. Moisture is given by (Wet Weight - Dry Weight)/Wet Weight). The
average moisture content was 39%
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters · A nominal cut-off grade of 0.7% Ni has been applied, based on
applied. similar open-pit operations.
Mining factors or assumptions · Assumptions made regarding possible mining methods, minimum mining · The large, relatively flat and shallow nature of this type of
dimensions and internal (or, if applicable, external) mining dilution. It is deposit dictates any mining would be by open pit methods. It has been assumed
always necessary as part of the process of determining reasonable prospects that the full strike length, width and depth of the modelled mineralisation
for eventual economic extraction to consider potential mining methods, but the above the 0.7% Ni cut-off can be economically mined.
assumptions made regarding mining methods and parameters when estimating
Mineral Resources may not always be rigorous. Where this is the case, this
should be reported with an explanation of the basis of the mining assumptions
made.
Metallurgical factors or assumptions · The basis for assumptions or predictions regarding metallurgical · Some information relating to nickel recovery from the
amenability. It is always necessary as part of the process of determining 'saprolite',
reasonable prospects for eventual economic extraction to consider potential
metallurgical methods, but the assumptions regarding metallurgical treatment material is known as some of this material has been processed and undergone
processes and parameters made when reporting Mineral Resources may not always preliminary test work. Similar test work is required to be carried out for
be rigorous. Where this is the case, this should be reported with an each of the project areas. At this stage of the project no overall recoveries
explanation of the basis of the metallurgical assumptions made. have been assumed for all the Wowo Gap Project Area deposits.
· For resource modelling no assumptions were made about process
methods or nickel recovery.
Environmen-tal factors or assumptions · Assumptions made regarding possible waste and process residue · The current proposal is to produce a bulk product suitable for
disposal options. It is always necessary as part of the process of determining smelting that will be transported offsite for processing. It has
reasonable prospects for eventual economic extraction to consider the
potential environmental impacts of the mining and processing operation. While been assumed that mine waste will be relatively low in total volume and
at this stage the determination of potential environmental impacts, comprise the 1 m to 5 m soil and volcanic ash overburden layer. This material
particularly for a greenfields project, may not always be well advanced, the is likely to be used for rehabilitation purposes after mining is complete.
status of early consideration of these potential environmental impacts should Low-grade material, mostly limonitic in composition, may be stockpiled, in
be reported. Where these aspects have not been considered this should be mined-out areas.
reported with an explanation of the environmental assumptions made.
Bulk density · Whether assumed or determined. If assumed, the basis for the · Density data was adopted from the Ravensgate 2011 report as it
assumptions. If determined, the method used, whether wet or dry, the frequency appears this is the only source of determined density information. In their
of the measurements, the nature, size and representativeness of the samples. report they indicate the representative and preferred in-situ bulk density for
resource modelling is 1.0 t/m3 for the "clay profile" (limonite-saprolite
· The bulk density for bulk material must have been measured by methods layer), and 2,0 t/m3 for the rocky Saprolite profile.
that adequately account for void spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within the deposit.
Queen & H&SC have, based on their experience, used an assumed default
density 0.9 t/m3 for the volcanic ash. This assumed density is unlikely to
· Discuss assumptions for bulk density estimates used in the evaluation have a large impact on the overall MRE tonnage as the volcanic ash layer has
process of the different materials. less overall volume compared to the other layers and does not contribute
tonnage at cut-off grades above about 0.7% Ni.
Classification · The basis for the classification of the Mineral Resources into · Resource classification is based on both the overall footprint of
varying confidence categories. the GPR coverage and drilling. A polygon that encompasses this was used to
flag the block model as follows:
· Whether appropriate account has been taken of all relevant factors
(ie relative confidence in tonnage/grade estimations, reliability of input · any Qva or Limonite-Saprolite blocks within it are classified as
data, confidence in continuity of geology and metal values, quality, quantity Indicated.
and distribution of the data).
· Rocky saprolite blocks classified as Inferred regardless of the
· Whether the result appropriately reflects the Competent Person's view polygon.
of the deposit.
· any blocks outside of classification polygon are Inferred
· This classification scheme is considered to take appropriate
account of all relevant factors, including the relative confidence in tonnage
and grade estimates, confidence in the continuity of geology and metal values,
and the quality, quantity and distribution of the drilling and GPR data
· The classification appropriately reflects the Competent Person's
view of the deposit.
Audits or reviews · The results of any audits or reviews of Mineral Resource estimates. · The current model has not been audited by an independent third
party
· This Mineral Resource estimate has been reviewed by Queen and
H&SC personnel and the resource report was internally peer reviewed by
H&SC. No material issues were identified because of these reviews.
Discussion of relative accuracy/ confidence · Where appropriate a statement of the relative accuracy and confidence · The relative accuracy and confidence level in the Mineral
level in the Mineral Resource estimate using an approach or procedure deemed Resource estimates are in line with the generally accepted accuracy and
appropriate by the Competent Person. For example, the application of confidence of the nominated JORC Mineral Resource categories. This has been
statistical or geostatistical procedures to quantify the relative accuracy of determined on a qualitative, rather than quantitative, basis, and is based on
the resource within stated confidence limits, or, if such an approach is not the estimator's experience with similar deposits elsewhere. The main factors
deemed appropriate, a qualitative discussion of the factors that could affect that affect the relative accuracy and confidence of the estimate are the drill
the relative accuracy and confidence of the estimate. hole spacing, the style of mineralisation and bulk density measurements.
· The statement should specify whether it relates to global or local · The estimates are local, in the sense that they are localised to
estimates, and, if local, state the relevant tonnages, which should be model blocks of a size considered appropriate for local grade estimation. The
relevant to technical and economic evaluation. Documentation should include tonnages relevant to technical and economic analysis are those classified as
assumptions made and the procedures used. Indicated Mineral Resources.
· These statements of relative accuracy and confidence of the estimate · This deposit remains unmined so there are no production records
should be compared with production data, where available. for comparison.
· Independent consultant Larry Queen conducted a review of the
various drilling and sample types to confirm that they are suitable to form
the basis of the Mineral Resource Estimates (MREs).
Site visits
· Comment on any site visits undertaken by the Competent Person and the
outcome of those visits.
· If no site visits have been undertaken indicate why this is the case.
· No site visits have been made by the Competent Persons for this
report as until recently, access to the area has been impossible due to
COVID19 travel restrictions. However, Mr. Queen has over 30 years of
experience in PNG and has served as Competent Person for the similar Ramu
Nickel Laterite and the Sewa Bay Nickel Laterite. Mr Queen has reviewed all
the documentation from the previous work and is confident Wowo Gap is broadly
similar to other tropical laterites in PNG.
Geological interpretation
· Confidence in (or conversely, the uncertainty of ) the geological
interpretation of the mineral deposit.
· Nature of the data used and of any assumptions made.
· The effect, if any, of alternative interpretations on Mineral
Resource estimation.
· The use of geology in guiding and controlling Mineral Resource
estimation.
· The factors affecting continuity both of grade and geology.
· The grade and lithological interpretation forms the basis for the
modelling. Grades have all been estimated constrained within the lateritic
layers (rock types).
· Based on experience at other nickel laterites in PNG and the
drill log and geochemical interpretation there is strong confidence in the
geological interpretation of the lateritic layers (rock types) of the deposit.
The upper layers, especially the limonite layer, are usually continuous, with
the absence of the limonite layer always due to erosion especially around the
incised streams. The grades including cobalt, are usually continuous and show
little lateral variability.
· Core recording, sample analysis and ground penetrating radar
(GPR) were applied to interpret the geological domains of deposit. The
overburden/limonite boundary was created using grade composites based on
aluminium and nickel percentage. Samples with greater than 20% Al(2)O(3) were
classified limonite. GPR data was used to define of the bottom of
limonite/saprolite top of rocky saprolite.
· The Wowo Gap deposit has been the subject of several previous
resource estimates, the most recent dated December 2011
(https://resmin.com.au/wp-content/uploads/docs/asx_announcements/2011/20111214%20Wowo%20Gap%20Resource%20Upgrade.pdf
(https://resmin.com.au/wp-content/uploads/docs/asx_announcements/2011/20111214%20Wowo%20Gap%20Resource%20Upgrade.pdf)
). All the resource models have been similar (i.e. the laterite occurs as a
layer-cake like deposit that drapes over the topography.) and vary mostly in
the amount of supporting data (drill holes and GPR)
· The GPR data was used to interpret and define a bottom of
Limonite-non rocky Saprolite and a bottom of rocky Saprolite surface. In the
stream incised areas where there was little, or no GPR data low laterite
thicknesses were used as defaults. This was done as it was assumed the
laterite profile would be largely removed along the streams.
· The logged lithology and the geochemistry was also used to define the
zone of Quaternary overburden (mainly volcanic ash, "Qva"), the logged zone of
limonite-non rocky saprolite and rocky saprolite.
· The Qva zone was used to define the bottom of overburden. Thus three
geological zones/layers were defined, overburden (Qva), limonite-non rocky
saprolite and rocky saprolite which in turn were used to guide and control the
mineral resource estimate.
· The interpreted overburden/Qva thickness ranges between 0 and 10m and
averages 0.5m, the limonite-non rocky saprolite between 0 and 23m and averages
3m, and the rocky saprolite between 0 and 20m and averages 3.8m
Dimensions
· The extent and variability of the Mineral Resource expressed as
length (along strike or otherwise), plan width, and depth below surface to the
upper and lower limits of the Mineral Resource.
· The drilled laterite covers an area of 8700 metres N-S by 3300 to
4000 meters E-S. The average thickness of the laterite above the rocky
saprolite is roughly 7 metres with maximum thickness of 19 metres
Estimation and modelling techniques
· The nature and appropriateness of the estimation technique(s) applied
and key assumptions, including treatment of extreme grade values, domaining,
interpolation parameters and maximum distance of extrapolation from data
points. If a computer assisted estimation method was chosen include a
description of computer software and parameters used.
· The availability of check estimates, previous estimates and/or mine
production records and whether the Mineral Resource estimate takes appropriate
account of such data.
· The assumptions made regarding recovery of by-products.
· Estimation of deleterious elements or other non-grade variables of
economic significance (eg sulphur for acid mine drainage characterisation).
· In the case of block model interpolation, the block size in relation
to
· the average sample spacing and the search employed.
· Any assumptions behind modelling of selective mining units.
· Any assumptions about correlation between variables.
· Description of how the geological interpretation was used to control
the resource estimates.
· Discussion of basis for using or not using grade cutting or capping.
· The process of validation, the checking process used, the comparison
of model data to drill hole data, and use of reconciliation data if available.
· Nickel and cobalt grades were estimated with using the ordinary
kriging (OK) estimation technique in Micromine software. Samples from each
hole were used and composited to the full width of the layer, making 1
composite per layer for each of the three layer; the mineralised domains were
limited to the three interpreted geological layers as noted above. The grade
distributions for nickel and cobalt are not strongly skewed so OK was an
appropriate estimation method; there are no extreme values requiring grade
cutting.
The three layers were estimated separately, i.e., with hard boundaries.
A two pass search strategy was used for OK estimation:
Search axis 1 axis 2 axis 3 max samples min total min hole
radians (m) radians (m) radians (m) per quadrant samples count
1 40 1000 1000 6 4 4
2 40 1200 1200 6 4 4
· The block model was setup as a 'grade thickness model' where both
grade and thickness are estimated for each of the 3 layers. Due to the steep
and widely undulating terrain, the block model and input grade and thickness
data from drilled was 'flattened' to a common dummy RL. This allowed a common
search orientation to be used during the OK estimation routine.
· The orientation of the search ellipsoid and variogram models was
isotropic in the horizontal plane of the flattened block model.
· The maximum extrapolation distance would be close to the maximum
search radii of 900m.
· There is a previous estimate (Ravensgate, 2011) that is broadly
compatible with the current MREs, but substantial differences in the
interpretation and modelling of mineralisation, as well as additional drilling
and more extensive and more detailed GPR technique, make detailed comparisons
to the 2011 MRE meaningless. The current MREs take appropriate account of
previous estimates, while acknowledging substantial differences in methodology
and data. H&SC also ran a non-grade thickness model, still using OK, but
with set block heights and on a block fraction basis. This block definition is
more common in gold or base metal models. The overall results of the check
model were closely comparable and gives confidence in the grade- thickness
methodology.
· The deposits remain unmined so there are no production records
for comparison.
· Only nickel and cobalt were estimated, so no potential
by-products or deleterious elements were assessed; consequently, no
assumptions are made regarding the correlation of variables.
· Dry bulk density was assigned by geological layer zone, based on
average values for available measurements quoted by Ravensgate (2011)
· The block size for the model is a constant 10x10 in Easting and
Northing with a variable block height for each of the 3 geological layers. In
this way the block model is three blocks high at each 10x10 cell. A 10x10 cell
size was chosen as this considers the steep and undulating terrain, thus
largely avoiding the need for block proportions or sub-blocking.
· The new model was validated in several ways - visual comparison
of block and drill hole grades, statistical analysis (summary statistics),
examination of grade-tonnage data, and comparison with previous estimates and
the check model.
· Average estimated grades are lower than average composite grades,
reflecting clustering in the drill hole data and slightly skewed grade
distributions.
· All the validation checks suggest that the grade estimates are
reasonable when compared to the composite grades, allowing for data
clustering.
Moisture
· Whether the tonnages are estimated on a dry basis or with natural
moisture, and the method of determination of the moisture content.
· All tonnes reported in the Mineral Resource are
estimated on a dry basis.
The moisture and dry bulk density were measured using a cylinder of core. The
volume of the sample was determined by measuring the length and diameter of
the sample. The wet sample is weighed first, the sample is then dried in a
drying oven under a constant temperature of 105°C, and then the dry weight is
determined. Moisture is given by (Wet Weight - Dry Weight)/Wet Weight). The
average moisture content was 39%
Cut-off parameters
· The basis of the adopted cut-off grade(s) or quality parameters
applied.
· A nominal cut-off grade of 0.7% Ni has been applied, based on
similar open-pit operations.
Mining factors or assumptions
· Assumptions made regarding possible mining methods, minimum mining
dimensions and internal (or, if applicable, external) mining dilution. It is
always necessary as part of the process of determining reasonable prospects
for eventual economic extraction to consider potential mining methods, but the
assumptions made regarding mining methods and parameters when estimating
Mineral Resources may not always be rigorous. Where this is the case, this
should be reported with an explanation of the basis of the mining assumptions
made.
· The large, relatively flat and shallow nature of this type of
deposit dictates any mining would be by open pit methods. It has been assumed
that the full strike length, width and depth of the modelled mineralisation
above the 0.7% Ni cut-off can be economically mined.
Metallurgical factors or assumptions
· The basis for assumptions or predictions regarding metallurgical
amenability. It is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider potential
metallurgical methods, but the assumptions regarding metallurgical treatment
processes and parameters made when reporting Mineral Resources may not always
be rigorous. Where this is the case, this should be reported with an
explanation of the basis of the metallurgical assumptions made.
· Some information relating to nickel recovery from the
'saprolite',
material is known as some of this material has been processed and undergone
preliminary test work. Similar test work is required to be carried out for
each of the project areas. At this stage of the project no overall recoveries
have been assumed for all the Wowo Gap Project Area deposits.
· For resource modelling no assumptions were made about process
methods or nickel recovery.
Environmen-tal factors or assumptions
· Assumptions made regarding possible waste and process residue
disposal options. It is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider the
potential environmental impacts of the mining and processing operation. While
at this stage the determination of potential environmental impacts,
particularly for a greenfields project, may not always be well advanced, the
status of early consideration of these potential environmental impacts should
be reported. Where these aspects have not been considered this should be
reported with an explanation of the environmental assumptions made.
· The current proposal is to produce a bulk product suitable for
smelting that will be transported offsite for processing. It has
been assumed that mine waste will be relatively low in total volume and
comprise the 1 m to 5 m soil and volcanic ash overburden layer. This material
is likely to be used for rehabilitation purposes after mining is complete.
Low-grade material, mostly limonitic in composition, may be stockpiled, in
mined-out areas.
Bulk density
· Whether assumed or determined. If assumed, the basis for the
assumptions. If determined, the method used, whether wet or dry, the frequency
of the measurements, the nature, size and representativeness of the samples.
· The bulk density for bulk material must have been measured by methods
that adequately account for void spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within the deposit.
· Discuss assumptions for bulk density estimates used in the evaluation
process of the different materials.
· Density data was adopted from the Ravensgate 2011 report as it
appears this is the only source of determined density information. In their
report they indicate the representative and preferred in-situ bulk density for
resource modelling is 1.0 t/m3 for the "clay profile" (limonite-saprolite
layer), and 2,0 t/m3 for the rocky Saprolite profile.
Queen & H&SC have, based on their experience, used an assumed default
density 0.9 t/m3 for the volcanic ash. This assumed density is unlikely to
have a large impact on the overall MRE tonnage as the volcanic ash layer has
less overall volume compared to the other layers and does not contribute
tonnage at cut-off grades above about 0.7% Ni.
Classification
· The basis for the classification of the Mineral Resources into
varying confidence categories.
· Whether appropriate account has been taken of all relevant factors
(ie relative confidence in tonnage/grade estimations, reliability of input
data, confidence in continuity of geology and metal values, quality, quantity
and distribution of the data).
· Whether the result appropriately reflects the Competent Person's view
of the deposit.
· Resource classification is based on both the overall footprint of
the GPR coverage and drilling. A polygon that encompasses this was used to
flag the block model as follows:
· any Qva or Limonite-Saprolite blocks within it are classified as
Indicated.
· Rocky saprolite blocks classified as Inferred regardless of the
polygon.
· any blocks outside of classification polygon are Inferred
· This classification scheme is considered to take appropriate
account of all relevant factors, including the relative confidence in tonnage
and grade estimates, confidence in the continuity of geology and metal values,
and the quality, quantity and distribution of the drilling and GPR data
· The classification appropriately reflects the Competent Person's
view of the deposit.
Audits or reviews
· The results of any audits or reviews of Mineral Resource estimates.
· The current model has not been audited by an independent third
party
· This Mineral Resource estimate has been reviewed by Queen and
H&SC personnel and the resource report was internally peer reviewed by
H&SC. No material issues were identified because of these reviews.
Discussion of relative accuracy/ confidence
· Where appropriate a statement of the relative accuracy and confidence
level in the Mineral Resource estimate using an approach or procedure deemed
appropriate by the Competent Person. For example, the application of
statistical or geostatistical procedures to quantify the relative accuracy of
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 of the estimate.
· The statement should specify whether it relates to global or local
estimates, and, if local, state the relevant tonnages, which should be
relevant to technical and economic evaluation. Documentation should include
assumptions made and the procedures used.
· These statements of relative accuracy and confidence of the estimate
should be compared with production data, where available.
· The relative accuracy and confidence level in the Mineral
Resource estimates are in line with the generally accepted accuracy and
confidence of the nominated JORC Mineral Resource categories. This has been
determined on a qualitative, rather than quantitative, basis, and is based on
the estimator's experience with similar deposits elsewhere. The main factors
that affect the relative accuracy and confidence of the estimate are the drill
hole spacing, the style of mineralisation and bulk density measurements.
· The estimates are local, in the sense that they are localised to
model blocks of a size considered appropriate for local grade estimation. The
tonnages relevant to technical and economic analysis are those classified as
Indicated Mineral Resources.
· This deposit remains unmined so there are no production records
for comparison.
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