REG - Thor Mining PLC - Kapunda Copper Resource <Origin Href="QuoteRef">THRL.L</Origin> - Part 3
12/02/2018 07:05
- Part 3: For the preceding part double click ID:nRSL5160Eb
· Stuart Metals (1992) - 4.3 Mt @ 1.10% copper for 47,000 tonnes of
contained metal.
·
· The assumptions made regarding recovery of by-products. No assumptions made. Potential by-products have not been modelled.
· Estimation of deleterious elements or other non-grade variables No deleterious elements have been estimated. For the majority of drillholes
of economic significance (eg sulphur for acid mine drainage characterisation). only copper was analysed.
· In the case of block model interpolation, the block size in The parent block size is 25 m E by 25 mN by 5.0 m RL. Sub blocking of 1mE by
relation to the average sample spacing and the search employed. 1mN by 1mRL was required to honour wireframe boundaries of the historic
underground workings. Sub blocks used parent block's grade.
Drilling is typically on 50m spaced sections with drillholes on sections
variably spaced 10m to 60m.
· Any assumptions behind modelling of selective mining units. The selective mining unit reflects ISR as the proposed extractive technique.
· Any assumptions about correlation between variables. No correlation between variables assumptions is made.
· Description of how the geological interpretation was used to Geological logs were used to map out the extents of copper oxides, secondary
control the resource estimates. and primary copper sulphides which were validated against Hylogger results and
core inspections undertaken by Terramin.
Surfaces generated included; base of copper oxides, top and base of secondary
copper sulphides and top of primary copper sulphides.
Estimation and modelling techniques (continued) · Discussion of basis for using or not using grade cutting or No top cuts were applied. This was considered appropriate as all copper grades
capping. of the 2m composites were below the average historic production grade of 19%
copper. The maximum assay from the oxide and secondary sulphide portions of
the Resource were respectively 6.3% and 17.7% copper.
· The process of validation, the checking process used, the Various visual and statistical checks were undertaken to validate modelling
comparison of model data to drill hole data, and use of reconciliation data if and grade interpolation. The global results are comparable with the reported
available. OK models with localised differences as expected.
Moisture · Whether the tonnages are estimated on a dry basis or with natural The Mineral Resource estimate is based upon dry tonnages. Moisture content has
moisture, and the method of determination of the moisture content. not been included.
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters A cut-off of 0.05% total copper for oxide and transitional is industry
applied. standard for ISR of copper projects.
Both Excelsior Mining Corp and Cirus Resources Ltd both use a resource cut-off
of 0.05% copper in their economic studies for their respective Gunnison Copper
Project and Florence Copper Project located in Arizona, USA.
Mining factors or assumptions · Assumptions made regarding possible mining methods, minimum The proposed use of the ISR method to extract copper from oxide and secondary
mining dimensions and internal (or, if applicable, external) mining dilution. sulphide copper mineralization was chosen based on several criteria including:
It is always necessary as part of the process of determining reasonable the majority of the ore body sitting below the water table; the fractured
prospects for eventual economic extraction to consider potential mining nature of the host rock providing transmissivity for fluids through the
methods, but the assumptions made regarding mining methods and parameters when preferentially mineralized fracture systems; the potential amenability of the
estimating Mineral Resources may not always be rigorous. Where this is the mineral species to the leaching and recovery process; the relatively low
case, this should be reported with an explanation of the basis of the mining visual and environmental impact of the ISR method (no bulk movement of rock,
assumptions made. no open cut pits or waste dumps, little noise or dust pollution) given the
proximity of the orebody to the local population.
Metallurgical factors or assumptions · The basis for assumptions or predictions regarding metallurgical While historic work has shown the mineral species to be targeted are amenable
amenability. It is always necessary as part of the process of determining to leaching by a number of lixiviant systems, detailed metallurgical test work
reasonable prospects for eventual economic extraction to consider potential has not been completed at this stage.
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.
Environmental factors or assumptions · Assumptions made regarding possible waste and process residue ISR allows the extraction of minerals with little physical disturbance to the
disposal options. It is always necessary as part of the process of determining environment. Since there is no physical movement of rock, there are no open
reasonable prospects for eventual economic extraction to consider the cut pits, shafts or dumps to manage on surface. ISR is a closed loop system
potential environmental impacts of the mining and processing operation. While that generates much smaller volumes of mining and hydrometallurgical effluents
at this stage the determination of potential environmental impacts, that require management than conventional operations. While little current
particularly for a greenfields project, may not always be well advanced, the environmental work has been carried out on the project to date, it is assumed
status of early consideration of these potential environmental impacts should that waste will be minimal and will be disposed of at an EPA licenced
be reported. Where these aspects have not been considered this should be facility.
reported with an explanation of the environmental assumptions made.
Bulk density · Whether assumed or determined. If assumed, the basis for the Historic density measurements were considered inappropriate as they did not
assumptions. If determined, the method used, whether wet or dry, the frequency make allowances for porosity of the rock.
of the measurements, the nature, size and representativeness of the samples.
ECR and Terramin collected 202 new density measurements from 19 drillholes
using a modified Archimedes method.
Previous Resource estimates used an averaged density. was between and BHS and
Northland used a density of 2.4 t/m(3) and ACC and Stuart Minerals 2.0
t/m(3). While the average interpolated density for the 2018 Mineral Resource
estimate is 1.84 t/m(3).
· The bulk density for bulk material must have been measured by The modified Archimedes method is considered an appropriate method as it
methods that adequately account for void spaces (vugs, porosity, etc), allows for water absorption, there was no slaking of the samples and no vugs
moisture and differences between rock and alteration zones within the deposit. were present.
· Discuss assumptions for bulk density estimates used in the Bulk density was modelled using the same domains and search parameters used
evaluation process of the different materials. for the copper mineralisation.
There is slight negative correlation with copper grade, presumed due to
increased kaolinization of the metasediments..
Classification · The basis for the classification of the Mineral Resources into The whole Kapunda Mineral Resource has been classified as Inferred.
varying confidence categories.
It is the view of the Competent Person that additional hydrological studies
and leaching tests are required before any portion of the Mineral Resource can
be classified at a higher confidence category than Inferred.
· Whether appropriate account has been taken of all relevant Historic data input is well documented and considered reliable.
factors (ie relative confidence in tonnage/grade estimations, reliability of
input data, confidence in continuity of geology and metal values, quality, Within the Resource the distribution of data and continuity is good.
quantity and distribution of the data).
· Whether the result appropriately reflects the Competent Person's The result appropriately reflects the Competent Person's view of the deposit.
view of the deposit.
Audits or reviews · The results of any audits or reviews of Mineral Resource The 2018 Mineral Resource Estimate has been reviewed Terramin Australia.
estimates.
Discussion of relative accuracy/ confidence · Where appropriate a statement of the relative accuracy and This Kapunda Mineral Resource estimate relates to copper oxide and secondary
confidence level in the Mineral Resource estimate using an approach or copper sulphide mineralisation within 100m of surface.
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 The Mineral Resource estimate is considered robust and representative. This
that could affect the relative accuracy and confidence of the estimate. model is intended only for use in aiding scoping study investigations into the
use if ISR.
The Mineral Resource estimate has been classified in accordance with the JORC
Code, 2012 Edition using a qualitative approach. All factors that have been
considered have been sufficiently documented in Section 1 and Section 3 of
this Table.
· The statement should specify whether it relates to global or The Kapunda Mineral Resource estimate relates to the copper oxide and
local estimates, and, if local, state the relevant tonnages, which should be secondary copper sulphide mineralisation where it is likely to have local
relevant to technical and economic evaluation. Documentation should include variability. The global assessment is more of a reflection of the average
assumptions made and the procedures used. tonnes and grade estimate.
· These statements of relative accuracy and confidence of the Historic production data is not relevant for the proposed ISR extraction
estimate should be compared with production data, where available. method as the ISR method will target the low grade halo to the historically
mined mineralisation.
Mining of the high grade supergene from 1844 to 1866, largely from underground
produced 13,500t of copper from 68,000t of ore at an average grade of 19.8%
copper. From 1867 to 1878 approximately 300,000t of tailings, waste rock and
low grade copper mineralisation mined from open cuts were leached to produce
1,600t of copper at an average grade of 0.5%.
This information is provided by RNS
The company news service from the London Stock Exchange
Utah's KD005 which returned from 45m, 27m @ 1.18% copper was resampled by Copper Range in 2007. Copper Range's resampling returned from 45m, 27m @ 1.20% copper. Utah's
deep intercept of primary copper sulphide in KD011 returned from 426m, 11m @ 2.00% copper was resampled by Terramin returned from 426m, 11m @ 1.89% copper and 0.1g/t
gold. Terramin's samples were a quarter cut of the remaining half core sample. (TZN ASX announcement - 1st Quarter Report, 29/4/2016) Other significant intersections from
drill core have been visually reviewed by Terramin and ECR staff. Terramin has also utilised a hand held XRF to validate copper assays of percussion holes stored at the
South Australian Drill Core Reference Library.
· The use of twinned holes. There were two sets of planned twin holes: KD001 twinned drillhole K015 and KD0019 twinned drillholes KP046 and K076. There are a further 6 pairs of drillholes that are close enough to be considered twins. As part of compiling data for the Kapunda Mineral Resource estimate it was deemed necessary to be comfortable with the wide variety of drilling and sampling methods used on the Kapunda Project over a number of years.In order to look at the issue it was decided to; · Compare summary statistics for the different drillhole series.· Compare a selection of twined holes.· Compare poor recovery core holes with good recovery drillholes · Compare rotary drilling with diamond drilling within a specific, geologically constrained spatial area.· The process entailed creating a 2m downhole composite set of drill assays and splitting these into their component drill series types for statistical analysis.Results;· The results in general show no significant bias due to drilling type.· Twin holes Q-Q plots indicate there is little bias.· There appears to be very little difference between holes with poor core recovery versus those with good core recovery.· While there are some individual difference between rotary and diamond holes, looking at a larger sample they appear to give relatively consistent results.
· Documentation of primary data, data entry procedures, data verification, data storage (physical and electronic) protocols. Primary data was recorded on paper log sheets, photocopies of originals were submitted as part of statutory reporting. These have subsequently been scanned to PDF and made available online at South Australian Resources and Information Gateway (SARIG)in the Resource and Energy Georeference Database. Terramin was also able to obtain digital data sets of the drill data from Copper Range Ltd and the digital data set used by Stuart Metals NL (Stuart Metals) for their 1992 Kapunda Resource estimate. Where differences were found between the data contained in the original company reports and the data provided by Stuart Metals database, the original companies' values were used. The data was entered into Excel spreadsheets before being imported into a Maxwell Geo Services' DataShed and QAQCR which was used to validate the data viz; overlapping intervals, excessive drillhole deviation, assay QAQC. Secondary validation by Maptek's Vulcan software and visual validation was also undertaken.
· Discuss any adjustment to assay data. No adjustments are made to reported summary intersections. The Mineral Resource estimate makes an allowance for core loss with lost intervals assumed to have a zero grade.
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. Mines Exploration established the original grid baseline parallel to main strike of mineralization with grid north at 335 degrees magnetic. All subsequent companies,
except for Copper Range used this grid. Initial survey control was by licensed surveyor using theodolite. Collars were fixed by theodolite surveys and metal pin bench
marks. Coordinate position 1000N 00E (collar of drillhole KV002). The majority of drill collar locations were recorded in company reports and in Stuart Metals digital
database. A few remaining drillhole collar locations were obtained from georeferenced maps. Originally drillhole collar RL's were calculated relative to drillhole KV002
but Northland in 1972 had the site resurveyed relative to the State Datum. To allow for the incorporation of drillhole data from Copper Range an affine transformation was
used to convert the earlier drillhole coordinates to MGA Zone 54 (GDA 94).
· Specification of the grid system used. The data is reported in grid system MGA Zone 54 (GDA94).
· Quality and adequacy of topographic control. In 1972 Northland Minerals contracted surveying consultants Alex & Symonds Pty Ltd to survey the site and locate drill collars. The level datum used throughout the grid and drillhole levelling is based upon a Lands Department Bench Mark Number 6921. A digital terrain model was created by Terramin from the survey's 528 survey points collected across the deposit. Drillhole collar RL's not picked up during this survey were then assigned a value from this surface.With the exception of the historic workings, the area has low relief. The site has a gentle slope to the south, over the 1,500m of strike length there is just a maximum difference of 25m in collar RLs.
Data spacing and distribution · Data spacing for reporting of Exploration Results. Drillhole spacings and sample interval lengths are considered appropriate.
· 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. The data spacing and the characteristics of the Kapunda mineralisation determined from reviewing historical drilling results, and visual inspections of the core are suitable for the defined Mineral Resource to be classified as Inferred for ISR. However, the protocol for estimation and reporting of Mineral Resources for exploitation using ISR has a number of additional steps compared to conventional mining and processing. Before any portion of the Kapunda Mineral Resource can be classified as Indicated or Measured pump testing and hydrogeological modeling will be required.
· Whether sample compositing has been applied. Field sample compositing was not undertaken on any of the diamond or percussion drill samples. Sample sizes are considered appropriate.
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. The orientation of the drilling is considered to be appropriate for the oxide copper and secondary copper sulphide mineralisation.
· 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. Drilling orientation is not deemed to have introduced any significant sampling bias.
Sample security · The measures taken to ensure sample security. Chain of custody management was not documented.
Audits or reviews · The results of any audits or reviews of sampling techniques and data. Prior to acquiring the Kapunda Project from Maximus Resources Ltd (Maximus), Terramin audited the Stuart Metals database against original reports and viewed drill core at
the South Australian Drill Core Reference Library. Historical density techniques were considered inappropriate and discarded. New measurements collected by TZN and ERC
show that density had previously been overcalled by over 10%. All data was loaded into a DataShed database and validated. Mineralisation was then visually checked and
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