REG - Thor Mining PLC - Kapunda Copper Resources - ASX clarification <Origin Href="QuoteRef">THRL.L</Origin> - Part 5
22/02/2018 10:37
- Part 5: For the preceding part double click ID:nRSV6523Fd
No new drillhole data or other exploration results are reported. All information has been compiled from "open file envelopes" available for download through the South
Australian Government's SARIG website-http://minerals.statedevelopment.sa.gov.au/
· easting and northing of the drill hole collar
· elevation or RL (Reduced Level - elevation above sea level in metres) of the drill hole collar
· dip and azimuth of the hole
· down hole length and interception depth
· 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. No new exploration results have been reported, all information is publically available from SARIG.
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. No new exploration results have been reported, all information is publically available from SARIG.
· 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. No metal equivalents are reported.
Relationship between mineralisation widths and intercept lengths · These relationships are particularly important in the reporting of Exploration Results. No new exploration results have been reported, all information is publically available from SARIG.
· 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 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. Figures 5 and 6 in main text.
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. No new exploration results have been reported, all information is publically available from SARIG.
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. The overall copper grade of the Mineral Resource estimate fits within the accepted parameters for copper ISR operations. Initial hydrogeological investigations show that
the en echelon and conjugate fracture systems provide transmissivity values within the range needed for successful ISR operations. The copper mineral species targeted are
considered to be potentially recoverable by ISR but laboratory testing needed to confirm this. The majority of the Mineral Resource sits below the current water table.
Laboratory testing of samples with different lixiviant systems is required to assess the recoverability of the ore and determine the mineral species that will exist in
the pregnant solutions.
Further work · The nature and scale of planned further work (eg tests for lateral extensions or depth extensions or large-scale step-out drilling). Following approvals from the Light Regional Council and regulators, a groundwater sample from the mineralized lode system will be collected and be used in the laboratory
testing of lixiviant systems on core samples to be undertaken by CSIRO. Further hydrogeological investigations including aquifer pump testing and beneficial use studies
will be undertaken. Understanding the hydrogeology of the area is critical to the Kapunda Project. Consequently, detailed hydrogeological investigations will be
undertaken to accurately modelgroundwater parameters. These models will allow ECR to undertake design work to ensure that there is no compromising existing users' water
quality or ability to access water. Groundwater Science has been engaged by ECR to carry out further groundwater studies.
· Diagrams clearly highlighting the areas of possible extensions, including the main geological interpretations and future drilling areas, provided this information is not commercially sensitive. Additional drilling is required to better define and potentially extend the southern limits of the Kapunda mineralisation, Figure 5.
· Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling areas,
provided this information is not commercially sensitive.
Additional drilling is required to better define and potentially extend the
southern limits of the Kapunda mineralisation, Figure 5.
Section 3: Estimation and Reporting of Mineral Resources
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 The 2018 Kapunda Mineral Resource estimate is based on drilling largely undertaken during the 1960's and 1970's and minor drilling undertaken in 2008. Data for the Mineral Resource estimate came from scanned copies of reports that cover all drilling periods available on "South Australian Resources Information Gateway" (SARIG). 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 for their 1992 Resource Estimate.
Resource estimation purposes.
· Data validation procedures used. Drillhole data was extracted from the original reports by Terramin and crossed checked with the digital datasets from Stuart Metals and Copper Range. Where differences
were found between the data contained in the original company reports and the provided Stuart Metals database, the original companies' values were used. The data was then
imported into a Maxwell Geo Services' DataShed and QAQCR were used to validate the data viz; overlapping intervals, excessive drillhole deviation, assay QAQC. Secondary
validation by Maptek's Vulcan software and visual validation.
Site visits · Comment on any site visits undertaken by the Competent Person and the outcome of those visits. The Competent Person has undertaken several site visits to the Kapunda project. These visits have verified that the dimensions of the physical site correspond with dimensions implied by the data sets. Copper oxide in the form of malachite is present in the mullock piles and copper efflorescence visible on many of the historic pit faces. Evidence of previous mining operations is visible with numerous open cuts, shafts and waste dumps still clearly visible. Visits have also been undertaken at the South Australian Drill Core Reference Library where over 100 Kapunda drillholes are stored.
· If no site visits have been undertaken indicate why this is the case. Site visits have been undertaken.
Geological interpretation · Confidence in (or conversely, the uncertainty of) the geological interpretation of the mineral deposit. The extensive surface and underground mining of the Kapunda lodes combined with the large amount of diamond drilling history of the Kapunda projects implies confidence in the current geological interpretation There are no alternative geological models of the secondary copper mineralisation (copper oxides and secondary copper sulphides). The vertical extent of secondary copper mineralisation modelled by Terramin using drillhole data is broadly comparable to the line "approximate lower limit of secondary enrichment" mapped out on a longitudinal section produced by the South Australian Mines Department in 1942 (Plan N2788).
· Nature of the data used and of any assumptions made. The 2018 Kapunda Resource utilized data from 78 diamond and 109 percussion holes with a combined meterage of 22,712.8m. Original lab assays were used. Resampling and lab
analysis of selected diamond core intervals and xrf analysis of drill chips from percussion holes stored at the South Australian Drill Core Reference Library by both
Copper Range Pty and Terramin confirmed the appropriateness and accuracy of historic assay methods. All original density measurements were considered inappropriate as
they did not make allowances for porosity of the rock. ECR and Terramin collected 202 new density measurements from 19 drillholes using a modified Archimedes method.
Historically the assumed density was between 2.0 t/m3 (ACC and Stuart Minerals) and 2.4 t/m3 (BHS and Northland) whereas the average calculated density of the 2018
Mineral Resource estimate is only 1.84 t/m3.
· The effect, if any, of alternative interpretations on Mineral Resource estimation. No alternative interpretations for the secondary copper enrichment have been put forward for serious consideration. Alternative geological interpretations may be
developed with further drilling but in the Competent Person's opinion they would not significantly affect the global resource estimate, but could affect local estimates.
· The use of geology in guiding and controlling Mineral Resource estimation. The 2018 Mineral Resource estimate was focused on defining the extent and nature of secondary (oxide/supergene) copper mineralisation. Important boundaries modelled were
the top and base of copper oxides, top and base of secondary sulphides and top of primary copper sulphides. The lower limit of (significant) weathering corresponds with
the base of secondary copper mineralisation. Detailed geological control has not been attempted at this stage. Primary copper mineralisation was bounded on the east by
the Mine Fault, which dips 65°E. The old workings immediately west of this structure occur principally in sets of en echelon lodes comprising of quartz-sulphide filled
fractures of which 28 were worked at an average width of 45cm.
· The factors affecting continuity both of grade and geology. The main controlling features of the secondary copper are seen to be proximity to primary mineralisation, the water table and the partial replacement of pyritic horizons
by copper within the supergene zone and depth of weathering.
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 The Mineral Resource has a strike length of 1700m, a plan width of 500m and has been limited to a maximum depth of 100m. Copper mineralisation was historically mined from surface and copper efflorescence is visible on many of the pit faces.
limits of the Mineral Resource.
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 Wireframes modelled included; top and base of copper oxide mineralisation, top and base of secondary copper sulphides and top of primary copper sulphides. Compositing of drillhole samples was completed at 2m (downhole) intervals, with composites flagged to identify the copper's mineralogy. The 2m composites were used for statistical analysis and continuity modeling.
parameters and maximum distance of extrapolation from data points. If a computer assisted estimation method was chosen include a description of computer software and Variogram models for copper were developed using Snowden's Supervisor software. Ordinary kriging estimation technique was used for estimation of copper grade. Estimation of blocks was limited to a maximum of three composites per hole from a maximum of three drillholes. Maximum distance of extrapolation was limited to 100m. There are no "extreme grade values" as all copper grades 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 estimate were respectively 6.3% and 17.7% copper. All geological modelling, block model construction, grade interpolation and reporting were completed using Maptek's Vulcan software.
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. Previous Mineral Resource estimates, calculated for mining by open cut are;· BHS (1969) - 5.5Mt @ 0.74% copper for 41,000t of contained metal.· Northland (1978)
- 6.3Mt @ 1.50% copper for 94,000t of contained metal.· ACC (1989) - 7.2 Mt @ 0.83% copper for 60,000 tonnes of contained metal· 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 of economic significance (eg sulphur for acid mine drainage characterisation). No deleterious elements have been estimated. For the majority of drillholes only copper was analysed.
· In the case of block model interpolation, the block size in relation to the average sample spacing and the search employed. The parent block size is 25 m E by 25 mN by 5.0 m RL. Sub blocking of 1mE by 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 control the resource estimates. Geological logs were used to map out the extents of copper oxides, secondary 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 capping. No top cuts were applied. This was considered appropriate as all copper grades 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 comparison of model data to drill hole data, and use of reconciliation data if available. Various visual and statistical checks were undertaken to validate modelling and grade interpolation. The global results are comparable with the reported OK models with
localised differences as expected.
Moisture · Whether the tonnages are estimated on a dry basis or with natural moisture, and the method of determination of the moisture content. The Mineral Resource estimate is based upon dry tonnages. Moisture content has not been included.
Cut-off parameters · The basis of the adopted cut-off grade(s) or quality parameters applied. A cut-off of 0.05% total copper for oxide and transitional is industry 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 mining dimensions and internal (or, if applicable, external) mining dilution. It is always necessary as The proposed use of the ISR method to extract copper from oxide and secondary sulphide copper mineralization was chosen based on several criteria including: the majority of the ore body sitting below the water table; the fractured nature of the host rock providing transmissivity for fluids through the preferentially mineralized fracture systems; the potential amenability of the mineral species to the leaching and recovery process; the relatively low visual and environmental impact of the ISR method (no bulk movement of rock, no open cut pits or waste dumps, little noise or dust pollution) given the proximity of the orebody to the local population.
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.
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 While historic work has shown the mineral species to be targeted are amenable to leaching by a number of lixiviant systems, detailed metallurgical test work has not been completed at this stage.
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