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| Date | 17 May 2022 |
| Time | 07:00:09 |
| Category | Miscellaneous |
| ID | 6895L |
/
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
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 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 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 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
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).
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.
(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 specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc). These examples should not be taken as limiting the broad meaning of sampling. · Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used. · Aspects of the determination of mineralisation that are Material to the Public Report. · In cases where 'industry standard' work has been done this would be relatively simple (eg 'reverse circulation drilling was used to obtain 1 m 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 is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (eg submarine nodules) may warrant disclosure of detailed information. |
· All the samples used in this Mineral Resource Estimate are from drill core. The core was obtained over three main drill campaigns. o Wacker drilling - 153 holes totaling 731 m. 3 cm diameter core- (nominal AQ). Only tested the non-rocky laterite. o Diamond core- (2003-2008 and 2014-201 5)161 holes totaling 3174.2 m. HQ or NQ core. o Tungsten carbide coring (2010-2011)- 297 holes totaling 1745.8 m. Only tested the non-rocky laterite. o Auger core (2014-2015)- 125 holes totaling 944.5 m. Only tested the non-rocky laterite. · The drill methods were chosen to provide a sample of the friable laterite that was relatively undisturbed. |
|
Drilling techniques |
· Drill type (eg core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc). |
· This Mineral Resource Estimate is based on results diamond core drilling (2003 - 2008), tungsten carbide-tipped core drilling (2010-2011), and (2014-2015) diamond core and custom auger core drilling. All holes are vertical. |
|
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. |
· As the core is recovered from the triple tube (NQ3), core recoveries are typically very good. The recoveries were logged and recorded in the database. · Core is recovered from the triple tube (NQ3) drilling to ensure good recovery. · Overall recoveries are>90% and there are no significant sample recovery problems. |
|
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. |
· Logging of the core recorded lithology, mineralogy, weathering, colour and other features of the samples. The core from each core run were placed in plastic core trays for logging and photographed, then sampled. Geotechnical logging was not conducted for mineralization purposes as there is no structural control to the mineralization. · 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 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. |
· Core samples were collected from half core, on typical 1 metre lengths through the laterite profile. · No non-core samples were taken. · The samples were submitted to Intertek Laboratory in Lae, Papua New Guinea (PNG) for preparation. All samples received were weighed and wet 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 split taken for fine pulverising to 95% passing -200 μm, with the remainder 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 Laboratory in Jakarta, Indonesia for assay of Ni, Co, Al2O3, CaO, Cr2O3, Fe2O3, K2O, LOI, MgO, MnO, Na2O, P2O5, SiO2 and LOI by fusion XRF. The sample preparation technique is considered appropriate for the style of mineralisation under consideration. · 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 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. |
· The 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. This method is considered a total assay. · No portable XRF machines were used to determine any element concentrations used in the grade determinations. · Sample preparation checks for fineness were carried out by the 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 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. |
· No verification was carried out. · In 2010 - 2011, a second twin hole was drilled within one metre of the original hole for every fourth or fifth hole drilled. These samples were sent to Ultratrace Laboratories for fusion XRF analysis. Comparison of the twin hole data was used to estimate short range variance (0.52). · Logging data was collected using a set of standard paper logging 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 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. |
· Diamond holes from both the 2003 - 2004 and 2007 drilling programs were surveyed by Arman Larmer Surveys Ltd Consulting Surveyors (PNG) 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 metres. 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. · 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. |
· Nominal drilling spacing for most of the area is 300 metres x 200 metres. For the areas covered by the 2014-2015 drilling the nominal drill hole spacing is 200 metres on 100 metres spaced east - west lines. · 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 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. |
· Lateritic nickel mineralisation develops broadly parallel to the topographic surface and vertical drilling orientation is generally unbiased. · No sampling bias from drillhole orientation is expected. The drillholes are vertical, with mineralisation generally horizontal and not obviously related to structure. |
|
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. |
(Criteria listed in the preceding section also apply to this section.)
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Criteria |
JORC Code explanation |
Commentary |
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Mineral tenement and land tenure status |
· Type, reference name/number, location and ownership including agreements or material issues with third parties such as joint ventures, partnerships, overriding royalties, native title interests, historical sites, wilderness or national park and environmental settings. · The security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area. |
· The Wowo Gap nickel laterite project is located near Embessa in the Oro Province of Papua New Guinea. The project is contained within EL 1165, which is owned by Niugini Nickel Limited, a wholly owned subsidiary of Corcel 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 government. There are no native title, historical, national park, or other impediments. · The tenement is currently in good standing pending renewal. |
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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, |
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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%) 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. |
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Drill hole Information |
· A summary of all information material to the understanding of the 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. |
· All the drill holes used for this Resource estimate were completed prior to the end of 2015. Details for those holes were reported in ASX announcements that can be found on the Resource Mining Corporation website (https://resmin.com.au/investor-centre/asx-announcements/) |
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Data aggregation methods |
· In reporting Exploration Results, weighting averaging techniques, 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. |
· Only Mineral Resources are being reported. As no exploration results are being reported, this section is not considered applicable. |
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Relationship between mineralisation widths and intercept lengths |
· These relationships are particularly important in the reporting of Exploration Results. · 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'). |
· Only Mineral Resources are being reported. As no exploration results are being reported, this section is not considered applicable. |
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Diagrams |
· Appropriate maps and sections (with scales) and tabulations of 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. |
· Only Mineral Resources are being reported. As no exploration results are being reported, this section is not considered applicable. |
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Balanced reporting |
· Where comprehensive reporting of all Exploration Results is not practicable, representative reporting of both low and high grades and/or widths should be practiced to avoid misleading reporting of Exploration Results. |
· Only Mineral Resources are being reported. As no exploration results are being reported, this section is not considered applicable. |
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Other substantive exploration data |
· Other exploration data, if meaningful and material, should be reported including (but not limited to): geological observations; geophysical 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. |
· Only Mineral Resources are being reported. As no exploration results are being reported, this section is not considered applicable. |
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Further work |
· The nature and scale of planned further work (eg tests for lateral extensions or depth extensions or large-scale step-out drilling). · Diagrams clearly highlighting the areas of possible extensions, including the main geological interpretations and future drilling areas, provided this information is not commercially sensitive. |
· The portion of the Mineral Resource corresponding to the area of the 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 and further resource modelling subdividing the laterite into limonite and saprolite layers may be sufficient to allow this portion of the Resource to be reclassified |
(Criteria listed in section 1, and where relevant in section 2, also apply to this section.)
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Criteria |
JORC Code explanation |
Commentary |
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Database integrity |
· Measures taken to ensure that data has not been corrupted by, for example, transcription or keying errors, between its initial collection and its use for Mineral Resource estimation purposes. · Data validation procedures used. |
· Logging data was collected using a set of standard paper logging 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. · 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:
· 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). |
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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. |
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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% Al2O3 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). 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 |
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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 |
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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 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. |
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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% |
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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. |
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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. |
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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. |
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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. |
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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. |
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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. |
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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. |
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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. |