REG - Thor Mining PLC - Kapunda Copper Resources - ASX clarification <Origin Href="QuoteRef">THRL.L</Origin> - Part 6

Thor EnergyAnnouncement

22/02/2018 10:35

- Part 6: For the preceding part double click  ID:nRSV6523Fe 

                                        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.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
 Environmental 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  ISR allows the extraction of minerals with little physical disturbance to the environment. Since there is no physical movement of rock, there are no open cut pits, shafts or dumps to manage on surface. ISR is a closed loop system that generates much smaller volumes of mining and hydrometallurgical effluents that require management than conventional operations. While little current environmental work has been carried out on the project to date, it is assumed that waste will be minimal and will be disposed of at an EPA licenced facility.                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                         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.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
 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,   Historic 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. Previous Resource estimates used an averaged density. was between and BHS and Northland used a density of 2.4 t/m3 and  ACC and Stuart Minerals 2.0 t/m3. While the average interpolated density for the 2018 Mineral Resource estimate is 1.84 t/m3.                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                         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.                                              The modified Archimedes method is considered an appropriate method as it allows for water absorption, there was no slaking of the samples and no vugs were present.       
 ·      Discuss assumptions for bulk density estimates used in the evaluation process of the different materials.                                                                                                                                                        Bulk density was modelled using the same domains and search parameters used 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 varying confidence categories.                                                                      The whole Kapunda Mineral Resource has been classified as Inferred.  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 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).       Historic data input is well documented and considered reliable.                                                                                                           
                                                                                                                                                                                                                                                                          Within the Resource the distribution of data and continuity is good.                                                                                                     
 ·      Whether the result appropriately reflects the Competent Person's view of the deposit.                                                                                                                                                                            The result appropriately reflects the Competent Person's view of the deposit.                                                                                             
 Audits or reviews                                                                                                                                                                                                                                                       ·      The results of any audits or reviews of Mineral Resource estimates.                                                                                                The 2018 Mineral Resource Estimate has been reviewed Terramin Australia.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
 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  This Kapunda Mineral Resource estimate relates to copper oxide and secondary copper sulphide mineralisation within 100m of surface. The Mineral Resource estimate is considered robust and representative. This 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 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.  The Kapunda Mineral Resource estimate relates to the copper oxide and secondary copper sulphide mineralisation where it is likely to have local variability. The global   
                                                                                                                                                                                                                                                                         assessment is more of a reflection of the average tonnes and grade estimate.                                                                                              
 ·      These statements of relative accuracy and confidence of the estimate should be compared with production data, where available.                                                                                                                                   Historic production data is not relevant for the proposed ISR extraction 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%.                                                                                                                                                    
 
 
·      These statements of relative accuracy and confidence of the estimate
should be compared with production data, where available. 
 
Historic production data is not relevant for the proposed ISR extraction
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