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ENERGY METALS LTD — Capital/Financing Update 2017
Dec 13, 2017
64845_rns_2017-12-13_67cc9647-caa9-42b3-b648-e9c6a730e83c.pdf
Capital/Financing Update
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ABN 63 111 306 533
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ASX ANNOUNCEMENT
14[th] December 2017
ASX Code - EME
For further information, contact:
Dr Weidong Xiang Energy Metals Limited
Telephone: 61 8 9322 6904 Facsimile: 61 8 9321 5240 Email:[email protected] Level 2, 28 Kings Park Road West Perth WA 6005
PO Box 1323 West Perth WA 6872
This report and further information are available on Energy Metals’ website at:
www.energymetals.net
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542 TONNES U3O8 MAIDEN JORC RESOURCE: MALAWIRI DEPOSIT (NT)
HIGHLIGHTS
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Inferred resource of 542 tonnes U3O8 at 1,288 ppm (100ppm cut-off) obtained for the historic Malawiri uranium deposit, eastern Ngalia Basin, NT.
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High grade deposit hosted in Mt Eclipse Sandstone buried by 80 to 100 m of younger cover.
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Mineralisation style similar to EME’s Bigrlyi deposit.
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Uranium potential of the undercover eastern Ngalia Basin (NT) highlighted.
Significant historic drill-hole intercepts from reprocessed gamma logs include:
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12.1m at 3,409 ppm eU3O8 from 164.6m in GCRD9
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6.1m at 2,105 ppm eU3O8 from 183.1m in GCRD9
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4.7m at 1,594 ppm eU3O8 from 189.0m in GCRD6
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11.9m at 946 ppm eU3O8 from 229.8m in GCRD21
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12.8m at 583 ppm eU3O8 from 126.2m in GCRD8
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12.4m at 577 ppm eU3O8 from 189.2m in GCRD3
Energy Metals Limited (ASX: EME) is pleased to advise that a uranium resource estimate has been obtained for the historic Malawiri deposit, located 30 km by road from Tilmouth Well in the eastern Ngalia Basin, Central Australia (Figure 1). The deposit lies on granted tenement ELR41 which is a joint venture between EME (52.1%) and Northern Territory Uranium Pty Ltd (NTU: 47.9%) with EME as operator of the JV.
The Malawiri deposit was discovered in 1980 by Central Pacific Minerals (CPM) following the discovery of the adjacent Minerva deposit by AGIP in 1978. Historical exploration work, including the drilling of 22 exploration holes, was carried out by CPM in the period 1980 to 1982. EME acquired CPM’s interest in the project in 2005, including all historical exploration records and drill core materials.
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The Ngalia Basin, which is some 12,600 km[2] in size, is recognised as one of the Northern Territory’s significant and most prospective uranium provinces (JSU Ngalia Basin Uranium Mineral System Project, Northern Territory Geological Survey, Record 2012-003) . In 2014, EME began a program of systematic documentation and evaluation of historical uranium deposits and prospects located on its Ngalia Basin tenure. Because of CPM’s meticulously kept historical exploration records, it was recognised that these data would be of sufficient quality for JORC-compliant resource estimation purposes provided certain geological criteria were met. In 2016, EME drilled a rotary mud/ diamond core hole at Malawiri, MARD004, between CPM drill lines where mineralisation was previously encountered. The purpose of the hole was to confirm the continuity and tenor of historically known mineralisation as well as provide core materials for geochemical and geotechnical test-work including bulk density. The results of the 2016 drilling program, which were consistent with historical results, were announced to the ASX on 27[th] September 2016. A review of available data by EME’s resource consultants CSA Global Ltd confirmed that appropriate criteria were met to permit resource estimation work at Malawiri to proceed.
No mineral resource estimate has previously been undertaken for the Malawiri deposit.
Exploration Results
The Malawiri deposit is a tabular, sandstone-hosted, uranium deposit located in the eastern Ngalia Basin. It is broadly similar in mineralisation style to EME’s Bigrlyi deposit in the western Ngalia Basin. Mineralisation is hosted in the Carboniferous Mt Eclipse Sandstone, which at Malawiri consists dominantly of coarse arkose and arkosic sandstone, with lesser conglomerate and shale. At Malawiri the Mt Eclipse Sandstone is unconformably overlain by 80 to 100m of relatively unconsolidated gravelly sands, silts and clays of the Cenozoic Whitcherry Basin (Figure 1). The Palaeozoic-Cenozoic unconformity is marked by a silcrete cap and an underlying zone of kaolinised sandstone (weathered Mt Eclipse). Mineralisation is stratiform in nature and occurs within a number of sub-vertically oriented, stacked, tabular lenses confined by conglomerate marker beds. Uranium mineralisation tends to be variably distributed along strike and at depth due in part to the effects of a late, oxidative uranium remobilisation event that also caused hematite overprinting.
The dimensions of the Malawiri mineralised domain (Figure 2) are approximately 400m along strike with an average plan width of 10-15m and a maximum modelled plan width of 35m. Stratigraphy and mineralisation dips sub-vertically and the width of the mineralised intervals varies from 0.3m to 12.6m, averaging 3.2m thickness. The mineralisation model extends from beneath the kaolinised sandstone unit at approx. 100m depth to 250m below surface. Drill-hole collar locations and other drilling details for historical CPM drill-holes are provided in Annexure 1.
Uraninite is the dominant uranium mineral in the sub-surface and it occurs in close association with pyrite and detrital-origin phyllosilicate minerals including biotite, clays and chlorite. Carbonate cement is pervasive in mineralised zones.
All historic CPM drill-holes were logged by independent geophysical contractors Geoex, Adelaide, using downhole gamma probe tools (for further details see the commentary regarding JORC reporting in Appendix 1). The downhole gamma probe was used as the primary analytical tool to measure eU3O8 grade. Drill core samples were assayed for uranium, however, these data were not considered to be sufficiently representative to be used in the resource estimation.
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Open file data from two historical AGIP holes were used to help constrain the along strike extension of mineralisation to the east.
Historically over 100 core samples were assayed by the so-called ‘closed can’ method at AMDEL laboratories, Adelaide, to determine the extent of possible radiometric disequilibrium; the results provide evidence for the existence of radium mobility relative to uranium and indicate the deposit is not in radiochemical equilibrium. This observation is has been confirmed by examination of comparative assay U3O8 data and gamma log eU3O8 data. Application of a disequilibrium correction (known as the Radioactive Equilibrium Factor or REF) is considered necessary to convert measured eU3O8 to actual U3O8 values (refer to JORC reporting commentary in Appendix 1 for further details).
Drill-hole information and gamma log data for all drill holes, including associated metadata and probe calibration records, were compiled from EME’s archives. Historical gamma logs were archived as a compilation of analogue printouts on paper charts; these were scanned at high resolution, digitised and converted to counts per second (cps) data at 10 cm intervals downhole. Using the calibration data and hole information the cps data were reprocessed to yield deconvolved eU3O8 values according to well established methods. Significant intercepts (minimum width 0.3m, maximum internal dilution 0.3m, cut-off grade 100ppm eU3O8, and grade x thickness value >100) are detailed in Annexure 2. Intercepts from EME’s 2016 drill-hole MARD004 have previously been reported. All relevant drilling data, gamma logging data and geological data including lithological logs have been converted to digital format, verified and loaded into EME’s database (a summary of the information is provided in Table 1 below).
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Figure 1. Map showing the location of the Malawiri Project on ELR41 in relation to EME’s surrounding exploration licence 24451 (green hatch), Ngalia Basin outline (dark blue), overlying Cenozoic basins (light blue). The Bigrlyi uranium deposit, towns, main roads (red) and drainages (blue) are also shown.
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Table 1. Database Summary of information used in the Resource Estimation
| Category | Total |
|---|---|
| Number of drill holes | 25* |
| Total metres drilled | 5,550.05 |
| Number of downhole surveyrecords | 106 |
| Number ofgamma logged intervals(at 10 cm) | 50,289 |
| Number of mineralised intervals based on 10 cm gamma-logging |
36 |
| Number of closed can assays used for REF estimationpurposes |
102 |
| Number of intervals with lithological data | 671 |
| Number of samples with measured bulk density | 217 |
*22 CPM drill-holes, 2 AGIP drill-holes and 1 EME drill-hole. The AGIP holes, drilled to the east of Malawiri, do not have available gamma logs and were used to constrain lithological continuity and the extent of mineralisation only.
Land Tenure
The Malawiri deposit is located on granted joint venture tenement ELR41 (EME: 52.1%, NTU: 47.9%). ELR applications 27 to 32 adjoin ELR41 and are owned 100% by NTU; they largely cover the adjacent Minerva prospect which lies about 1 km to the ESE. However, a small proportion of the Malawiri deposit extends on to neighbouring tenement ELR28 to the immediate south of ELR41; accordingly, the resource has been truncated at the boundary so that only the portion of the resource residing on ELR41 is reported here. The ELRs are embedded within surrounding Exploration Licence 24451, which is part of EME’s 100% owned Ngalia Regional Project (Figure 1).
The Malawiri deposit is located on the Napperby pastoral lease over which a Native Title claim was determined by consent in 2013. Currently, resource areas are not affected by any Aboriginal heritage or cultural sites.
Resource Estimation Procedure
Mineralised envelopes were interpreted and wireframed using downhole gamma log data. The downhole eU3O8 data was converted to U3O8 grade by application of REF corrections to account for radiochemical disequilibrium associated with radium mobility. The wireframes were constructed on the basis of a sectional interpretation in which the boundaries were extrapolated to half the nominal section spacing beyond the extents of current drilling. Using the digital lithological logs, digital models were also generated for the unconformity surfaces (Figure 2).
The downhole U3O8 data were composited over mineralised intervals of 0.5 m width; and statistical and geostatistical analyses were then performed. The block model was created and filled following application of a coordinate transformation to provide a constant orientation (flattening) of mineralised bodies for interpolation purposes. Because the distribution of uranium grades consists of several populations, the Multiple Indicator Kriging (MIK) method was used for interpolation of grades in the block model. The dimensions of the parent blocks were set at 2 х 0.125 х 2 m without sub-celling. An average bulk density of 2.45 t/m[3] , as measured from Malawiri core samples, was used. The distribution of U3O8 grade values obtained is shown in Figure 3 and the resulting resource estimate, which is classified as inferred, is provided in Table 2 for 100 ppm U3O8 cut-off grade.
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Figure 2. Wireframe models showing the mineralised domain and unconformity-related surfaces together with drill-hole traces.
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Figure 3. Distribution of U3O8 grade for the Malawiri deposit.
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Summary
The Mineral Resources are summarised in Table 2 for a 100ppm U3O8 cut-off grade:
Table 2. Estimate of Mineral Resources for the Malawiri Deposit as at 14 December 2017
| Category | Volume, '000 m3 |
Kilotonnes | Bulk Density, t/m3 |
Grade U3O8 ppm |
U3O8 tonnes |
U3O8 Mlb | U% | U, t |
|---|---|---|---|---|---|---|---|---|
| Inferred | 172.0 | 421.3 | 2.45 | 1,288 | 542 | 1.20 | 0.109 | 460 |
Notes:
1. The Mineral Resources are for a 100% interest in the associated joint venture and not the Mineral Resources attributable to the individual joint venture partners.
2. Mineral Resources are based on 100 ppm cut-off grade per resource block.
3. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
4. Mineral Resources are based on JORC-2012 definitions.
5. Mineral Resources are based on a bulk density of 2.45 t/m[3] .
6. Calculations and unit conversions may not yield exact figures due to rounding.
The Mineral Resources have been classified and reported in accordance with JORC (2012) requirements. The resource classification is based on the assessed level of confidence in sample methods used, geological interpretation, drill spacing and geostatistical measures.
Because the resource is based on a relatively small number of drill holes compared with other deposits, Energy Metals believes there is scope for expansion of the resource particularly by along strike extensional drilling to the west and at depth where mineralisation is open. Additionally, the deposit geology could be repeated in folded Mt Eclipse strata within synclinal and anticlinal structures to the north of the current resource area.
Although Malawiri is a small deposit, it is relatively high grade. Due to the proximity of the larger Minerva deposit located approx. 1km to the ESE and determined by AGIP to be of similar grade, there is a possibility of a combined future mining development. However, little work has been done at Malawiri or Minerva since 1982; modern investigations of deposit metallurgy, hydrology, rock properties and additional uranium series equilibrium and drill test work will be required to advance the project in the medium term. Although current uranium market conditions are difficult, Energy Metals remains committed to its strategy of data compilation, resource evaluation and drill testing of historical uranium deposits on its Ngalia Basin tenure.
For and on behalf of the Board.
Weidong Xiang Managing Director 14[th] December 2017
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Competent Persons Statement
The information in this report that relates to Mineral Resource estimation is based on information compiled by Mr Dmitry Pertel, Principal Consultant Geologist, CSA Global Ltd and Dr Maxim Seredkin, Principal Consultant Geologist, CSA Global Ltd. Information in this report relating to the interpretation and determination of gamma probe results is based on information compiled by Mr Evgeny Sirotenko, consultant geophysicist, under supervision of Dr Maxim Seredkin, Principal Consultant Geologist, CSA Global Ltd. Mr Pertel is a member of the Australian Institute of Geoscientists (MAIG) and is an employee of CSA Global. Dr Seredkin is a Fellow of the Australasian Institute of Mining and Metallurgy (FAusIMM), a member of the Australian Institute of Geoscientists (MAIG), and is an employee of CSA Global. Mr Pertel and Dr Seredkin have sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which they are undertaking to qualify as Competent Persons as defined by the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves – The JORC Code (2012)”, and Mr Pertel and Dr Seredkin both consent to the inclusion in this report of the matters based on the information in the form and context in which it appears.
Information in this report relating to exploration results, data, cut-off grades and QAQC analysis is based on information compiled by Dr Wayne Taylor and Mr Daniel Jordan. Dr Taylor and Mr Jordan are both members of the AIG and full time employees of Energy Metals Ltd. They both have sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which they are undertaking to qualify as a Competent Person as defined in the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves – The JORC Code (2012)”. Dr Taylor and Mr Jordan both consent to the inclusion of the information in the report in the form and context in which it appears.
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Annexure 1. Collar coordinates and drill-hole details for historical CPM drilling at the Malawiri deposit, GDA94 datum, Zone 53.
| HOLE ID | DRILL TYPE* |
PRE- COLLAR DEPTH (m) |
TOTAL DEPTH (m) |
DIP Degrees |
AZI- MUTH Magnetic |
NORTHING (MGA53) |
EASTING (MGA53) |
HEIGHT (RL) m |
|---|---|---|---|---|---|---|---|---|
| GCRD1 | RM/DH | 110.87 | 219.15 | -90 | 180 | 7,491,689.89 | 232,429.36 | 569.36 |
| GCRD2 | RM/DH | 147.00 | 188.40 | -69 | 189 | 7,491,238.81 | 231,320.09 | 568.95 |
| GCRD3 | RM/DH | 151.00 | 284.20 | -70 | 197 | 7,491,265.57 | 231,264.12 | 569.06 |
| GCRD4 | RM/DH | 156.00 | 263.30 | -70 | 197 | 7,491,259.14 | 231,327.48 | 569.05 |
| GCRH5 | RM | 88.00 | 88.00 | -90 | 180 | 7,491,459.20 | 230,061.75 | 568.11 |
| GCRD6 | RM/DH | 150.00 | 216.80 | -65 | 197 | 7,491,285.72 | 231,337.97 | 569.13 |
| GCRD7 | RM/DH | 156.00 | 250.70 | -65 | 197 | 7,491,319.39 | 231,283.47 | 569.16 |
| GCRD8 | RM/DH | 150.00 | 240.00 | -65 | 190 | 7,491,265.00 | 231,187.00 | 569.16 |
| GCRD9 | RM/DH | 171.00 | 257.00 | -65 | 190 | 7,491,290.56 | 231,193.65 | 569.03 |
| GCRD10 | RM/DH | 123.00 | 255.00 | -65 | 190 | 7,491,308.51 | 231,075.08 | 568.86 |
| GCRD11 | RM/DH | 162.00 | 183.00 | -65 | 190 | 7,491,328.05 | 231,017.66 | 568.68 |
| GCRD12 | RM/DH | 156.00 | 219.00 | -75 | 190 | 7,491,321.86 | 230,953.96 | 568.54 |
| GCRD13 | RM/DH | 144.00 | 211.50 | -65 | 190 | 7,491,357.23 | 231,025.04 | 568.79 |
| GCRD14 | RM/DH | 150.00 | 156.80 | -65 | 190 | 7,491,347.35 | 231,084.96 | 568.91 |
| GCRH15 | RM | 184.00 | 184.00 | -75 | 190 | 7,491,352.20 | 231,086.03 | 568.89 |
| GCRH16 | RM | 36.00 | 36.00 | -75 | 190 | 7,491,285.95 | 231,192.17 | 568.82 |
| GCRD17 | RM/DH | 157.00 | 298.20 | -65 | 190 | 7,491,319.41 | 231,200.64 | 569.04 |
| GCRD18 | RM/DH | 150.00 | 294.80 | -75 | 190 | 7,491,313.56 | 231,076.35 | 568.88 |
| GCRD19 | RM/DH | 148.00 | 261.00 | -65 | 190 | 7,491,298.42 | 231,195.19 | 568.93 |
| GCRD20 | RM/DH | 143.40 | 292.80 | -70 | 190 | 7,491,362.13 | 230,849.10 | 568.46 |
| GCRD21 | RM/DH | 138.40 | 255.00 | -70 | 197 | 7,491,276.08 | 231,333.03 | 569.18 |
| GCRD22 | RM/DH | 136.30 | 181.60 | -65 | 197 | 7,491,244.48 | 231,255.76 | 569.03 |
*RM/DH = Rotary Mud/Diamond Core
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Annexure 2. Significant eU3O8 (Deconvolved Gamma Log) intercepts from the Malawiri deposit based on the criteria: Minimum width 0.3m, maximum internal dilution 0.3m, 100ppm eU3O8 cut-off grade; Grade x Thickness >100. Grade x Thickness (GT) values >1000 are highlighted in bold italics.
| Hole ID | From | To | Width (m) * |
Grade eU3O8 (ppm) |
Cut-off (ppm) | Grade x Thickness |
|---|---|---|---|---|---|---|
| GCRD2 | 137.40 | 139.20 | 1.80 | 1,514 | 100 | 2,726 |
| incl. | 138.20 | 139.20 | 1.00 | 2,498 | 500 | 2,498 |
| GCRD2 | 140.80 | 141.50 | 0.70 | 150 | 100 | 105 |
| GCRD2 | 142.40 | 147.00 | 4.60 | 460 | 100 | 2,114 |
| incl. | 144.20 | 145.30 | 1.10 | 1,267 | 500 | 1,394 |
| GCRD2 | 148.60 | 151.50 | 2.90 | 395 | 100 | 1,145 |
| incl. | 150.60 | 151.20 | 0.60 | 1,100 | 500 | 660 |
| GCRD2 | 180.50 | 183.40 | 2.90 | 605 | 100 | 1,755 |
| incl. | 181.20 | 182.30 | 1.10 | 1,264 | 500 | 1,391 |
| GCRD3 | 183.90 | 185.10 | 1.20 | 135 | 100 | 162 |
| GCRD3 | 189.20 | 201.60 | 12.40 | 577 | 100 | 7,158 |
| incl. | 191.40 | 193.50 | 2.10 | 1,036 | 500 | 2,175 |
| incl. | 199.60 | 200.90 | 1.30 | 2,099 | 500 | 2,728 |
| GCRD3 | 214.70 | 216.50 | 1.80 | 182 | 100 | 328 |
| GCRD3 | 218.60 | 224.10 | 5.50 | 695 | 100 | 3,824 |
| incl. | 219.30 | 221.50 | 2.20 | 1,525 | 500 | 3,355 |
| GCRD3 | 226.40 | 230.00 | 3.60 | 143 | 100 | 516 |
| GCRD4 | 172.80 | 177.50 | 4.70 | 1,231 | 100 | 5,787 |
| incl. | 173.80 | 177.10 | 3.30 | 1,631 | 500 | 5,384 |
| GCRD4 | 190.80 | 192.30 | 1.50 | 342 | 100 | 513 |
| incl. | 191.50 | 191.90 | 0.40 | 1,035 | 500 | 414 |
| GCRD4 | 202.50 | 205.20 | 2.70 | 505 | 100 | 1,363 |
| incl. | 203.30 | 204.50 | 1.20 | 797 | 500 | 956 |
| GCRD6 | 189.00 | 193.70 | 4.70 | 1,594 | 100 | 7,493 |
| incl. | 190.40 | 193.40 | 3.00 | 2,380 | 500 | 7,141 |
| GCRD6 | 207.60 | 209.00 | 1.40 | 254 | 100 | 356 |
| GCRD8 | 122.90 | 123.90 | 1.00 | 105 | 100 | 105 |
| GCRD8 | 126.20 | 139.00 | 12.80 | 583 | 100 | 7,467 |
| incl. | 126.70 | 127.20 | 0.50 | 595 | 500 | 298 |
| incl. | 127.30 | 131.90 | 4.60 | 1,058 | 500 | 4,869 |
| incl. | 136.50 | 137.80 | 1.30 | 797 | 500 | 1,036 |
| GCRD9 | 164.60 | 176.70 | 12.10 | 3,409 | 100 | 41,243 |
| incl. | 165.90 | 168.90 | 3.00 | 11,774 | 500 | 35,322 |
| incl. | 174.20 | 176.30 | 2.10 | 2,343 | 500 | 4,921 |
| GCRD9 | 179.40 | 181.30 | 1.90 | 153 | 100 | 290 |
| GCRD9 | 183.10 | 189.20 | 6.10 | 2,105 | 100 | 12,838 |
| incl. | 186.20 | 188.70 | 2.50 | 4,792 | 500 | 11,979 |
| GCRD11 | 116.70 | 118.90 | 2.20 | 190 | 100 | 419 |
| GCRD11 | 125.40 | 126.80 | 1.40 | 123 | 100 | 172 |
| GCRD11 | 134.30 | 135.40 | 1.10 | 137 | 100 | 150 |
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| GCRD19 | 219.70 | 220.50 | 0.80 | 170 | 100 | 136 |
|---|---|---|---|---|---|---|
| GCRD21 | 229.80 | 241.70 | 11.90 | 946 | 100 | 11,261 |
| incl. | 231.60 | 237.50 | 5.90 | 1,154 | 500 | 6,807 |
| incl. | 239.00 | 241.00 | 2.00 | 1,751 | 500 | 3,502 |
| GCRD22 | 123.90 | 129.40 | 5.50 | 210 | 100 | 1,155 |
*Note: true widths of mineralised zones are approximately 30-50% of intercept width depending on inclination of hole.
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Appendix 1: JORC Table 1
The following commentary is provided to ensure compliance with the JORC (2012) requirements for the reporting of Mineral Resource Estimates as discussed above for the Malawiri Deposit located on tenement ELR41.
JORC Table 1 Section 1 – Key Classification Criteria
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Sampling techniques |
Nature and quality of sampling (e.g. cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as downhole 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 (e.g. ‘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 (e.g. submarine nodules) may warrant disclosure of detailed information |
The primary sampling instrument at the Malawiri was the downhole gamma tool (or ‘probe’) which was used to obtain a total gamma count reading down each drill-hole. Drilling was by rotary mud (RM) and diamond core (DD) drilling methods with NNE-SSW oriented drill lines on 60 - 120 m spacing and closer 30 m spacing within the primary mineralised zones. Drill holes were sub-vertical (due to unconsolidated overburden & unconformity at 100m depth) to optimally intersect steeply-dipping mineralisation. Original analogue gamma log data was digitised at 10 cm intervals downhole and converted to standard format LAS files followed by calculation of equivalent U3O8 (eU3O8) grades (see below for further information on gamma log processing procedures). The total count gamma logging method used here is a common method used to estimate uranium grade where the radiation contribution from thorium and potassium is small (as is the case for sandstone-hosted deposits of the Bigrlyi- type considered here). Gamma radiation is measured from a volume surrounding the drill hole that has a radius of approximately 35 cm. Therefore the gamma probe samples a much larger volume than drill spoil or drill core samples recovered from a drill-hole of normal diameter; gamma logging is considered to provide a more representative sample of the mineralised body and is preferred over geochemical assay of drill samples for resource estimation purposes. Estimates of uranium concentration determined from gamma ray measurements are based on the initial assumption that the uranium is in secular equilibrium with its daughter products (radionuclides), which are the principal gamma ray emitters along the U-series decay chain. If uranium is in disequilibrium as a result of the redistribution (depletion or enhancement) of uranium relative to its daughter radionuclides, then the true uranium concentration in the holes logged using the gamma probe will differ from that reported by gamma measurements. For the present resource estimation work at Malawiri an analysis of historical closed can measurements indicates that a disequilibrium correction (known as the Radioactive Equilibrium Factor or REF) is necessary (see below). |
| Drilling techniques |
Drill type (e.g. core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc.) and details (e.g. 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.). |
Rotary mud (RM) and diamond drilling (DD) methods were used by Central Pacific Minerals (CPM) between the years 1979 – 1982. The programs primarily consisted of RM pre- collars to approximately 150m depth (unconformity) with BQ and/or NQ DD tails. Three pure RM holes were drilled from surface to target depth one of which included a water bore. RM drilling used blade & tri-cone roller bits. Holes were cased with 100-150mm PVC as well as NQ and or NW casing to pre-collar depths. NQ, BW & BQ casing was run >150 m depths. No orientation marks were observed on historical core, however, geotechnical features were logged and recorded by CPM. Modern drilling by EME used the RM method to the unconformity followed by NQ2 DD coring. RM pre-collar was drilled with 4 3/4” roller bits, 3 7/8” PCD bits and cased off with HQcasing. NQ2 DD tails were drilled to target depth. All |
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| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| DD cores were orientated using a NQ2 orientation tool set. | ||
| 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. |
Drill spoil & core recovery is not relevant to the sampling method used (i.e. downhole gamma logging). However, pre- collar RM drill cuttings were collected by a timed interval method factoring in mud density & viscosity, annulus size and up-hole velocity of the fluids from depth. It should be noted that the RM drilling method does not necessarily provide an accurate sample due to loss of fines and potential for up-hole contamination. Core sampling recoveries in the DD tails were determined by comparison of recovered core to the run drilled and this information was recorded on the geological logging sheets. CPM recorded core recoveries of >94% whilst EME’s modern drill core recoveries were 100%. To achieve maximum core recoveries CPM and EME both cased off the pre-collars to avoid collapse of the overlying unconsolidated Cenozoic units. No relationship exists between sample recovery and grade due to the type of sampling method applied (i.e. downhole gamma logging). |
| 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. |
RM drill cuttings were logged at the time of drilling by CPM geologists and the hard copy lithological logs were converted to digital format by EME geologists using EME’s standard codes. Seventeen historical DD core holes were re-logged by EME geologists for lithology, colour, grain-size, stratigraphic unit, oxidation state, alteration, cementation, weathering and other features; data was recorded digitally and core was photographed. Additionally core was logged for structure using a goniometer to obtain alpha/beta measurements, dip & dip direction of varying structure types where possible. The coded data was verified according to EME’s standard logging look-up tables. The re-logs were found to be in good agreement with previous logging records, which provided confidence in the quality of original CPM logging. Scintillometer and Niton portable XRF measurements were undertaken on historical and modern core at 20 cm intervals through mineralised zones to confirm the width of mineralisation. EME geologists logged the modern RM cuttings and drill core from hole MARD004 using in-house lithological and structural templates. In addition, core was photographed and mineralised intervals were later scanned by the hylog method to determine spectral mineralogy. Scintillometer measurements were undertaken over mineralised zones to confirm the width of mineralisation. The coded data was verified according to EME’s standard logging look-up tables 100% of relevant intersections have been logged. |
12
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Subsampling 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 subsampling 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. |
For historical holes core was originally split into samples of half core for assay work. Half core was quartered for duplicate checks. Historically, CPM assayed for uranium as well as V, Cu, Cr and Au. The uranium assay data were not used for the resource estimation work as they are not considered sufficiently robust nor representative in comparison with the gamma logging measurements. Historical closed can assay data undertaken by AMDEL on 102 samples was used to evaluate uranium series disequilibrium and determine the Radioactive Equilibrium Factor (i.e. the disequilibrium correction). For modern hole MARD004, mineralised intervals were sampled at 0.4m spacing and assayed for a complete range of elements at ALS laboratories, Perth. Standard EME and laboratory QAQC procedures were applied. Interval matched uranium assay data was used to confirm the Radioactive Equilibrium Factor but this data was not used directly for mineral resource estimation purposes. |
| 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 (e.g. standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy (i.e. lack of bias) and precision have been established. |
The gamma tools used for downhole gamma ray measurements were calibrated and operated by geophysical contractors Geoex Pty Ltd of South Australia during the period 1980-1982. Calibration information including k-factors and deadtime corrections and hole information including hole diameter, casing depths/type and fluid levels/type were recorded for each hole. The accuracy and reproducibility of the probe data were monitored using two on-site standard radioactive sources (a low-level and a high-level source) and the monitoring data was included on each paper log and deemed satisfactory. Historic drill holes were logged with two different gamma ray tools depending on grade. The initial run was undertaken with the L1 or lithology gamma probe which employed a sensitive 4 x 1 inch NaI detector crystal. Intervals of significant mineralisation (off-scale on the L1 probe) were re- probed with the O1 or ‘ore’ gamma probe which employed the less sensitive 1 x ¾ inch NaI detector crystal. Eight of the 22 drill holes were logged with a neutron probe for the purposes of downhole stratigraphic comparison. This data has not been digitised or used for resource estimation purposes. The counts per second (cps) downhole gamma data were recorded on paper charts with an analogue pen recorder; for some holes the cps data was also recorded in digital printout form for the O1 probe and CPM determined eU3O8 values using a polynomial calibration equation. This data however was not used for the present resource estimation work, instead the original paper logs were scanned, digitised and re-processed. Logging parameters including the time constant, logging speed and chart scale were recorded. Both L1 and O1 paper logs were digitised by EME’s geophysical contractor and converted into digital standard-format LAS files. LAS file data were converted to equivalent U3O8 values (eU3O8 in ppm) using the specified probe calibration factors and taking into account drill hole size, fluid levels and other parameters. The eU3O8 data was filtered (deconvolved) to correct for smearing of the gamma signal at mineralised interfaces so that true grades and thicknesses more closely reproduce actualgrade. The eU3O8 grades were calculated |
13
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| by consultant geophysicist Mr Evgeny Sirotenko under the supervision of Dr Maxim Seredkin using the well-established methodology of Khaikovich and Shashkin, widely tested and upheld in the evaluation of uranium deposits in Kazakhstan and the former USSR. Modern downhole gamma measurements on hole MARD004 were performed with a 33mm Auslog probe, serial number S937. The probe was calibrated at the Adelaide test pits, South Australia. The calibration data were evaluated by consultant geophysicist Mr David Wilson of 3D Exploration Pty Ltd and judged to be satisfactory. The MARD004 downhole gamma log was recorded by EME staff using Auslog equipment and software, and employing standard, documented procedures. Hole information including hole diameter, casing depths and type, and fluid levels were recorded. The gamma log was output as a standard-format LAS file, which was processed to yield eU3O8 values by consultant geophysicist Mr David Wilson of 3D Exploration Pty Ltd. |
||
| 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. |
A LAS file from one historical hole with significant uranium intersections was independently reprocessed by consultant geophysicist Mr David Wilson of 3D Exploration Pty Ltd. Comparison of eU3O8 grade composites between the Wilson and Sirotenko datasets indicates that agreement is within 1% which is deemed more than satisfactory. No twinned holes are available from the historical dataset. However, hole MARD004 was sited between two lines of historical drill holes spaced 65m apart and provides confirmation of the continuity and grade of historically defined mineralised zones. Historical data including paper gamma logs, assay certificates and lithological logs were stored in archive boxes in EME’s library. The data is a complete record of CPM’s exploration works conducted from 1979 through 1983. Historically, CPM undertook ‘closed can’ eU3O8 and uranium assay measurements at The Australian Mineral Development Laboratories (AMDEL), Adelaide, on 96 core samples (plus additional repeats) in order to investigate potential uranium series disequilibrium in the prospect. An evaluation of this data, combined with check data from interval-matched assay and eU3O8 values from hole MARD004, indicates mineralised zones are affected by radium mobility and REF corrections are deemed necessary. Relative to eU3O8grade the following REF corrections have been determined: 50-250 ppm – 0.86, 250- 500 ppm – 1.08, >500 ppm – 1.27. The correction results in an increase in U3O8 grade relative to the eU3O8 measurements for all mineralisation >250ppm eU3O8. The eU3O8 assay data was deconvolved and corrected for radiochemical disequilibrium by application of a REF value as discussed above. |
| Location of data points |
Accuracy and quality of surveys used to locate drillholes (collar and downhole surveys), trenches, mine workings and other locations used in Mineral Resource estimation. Specification of the grid system used. Quality and adequacy of topographic control. |
Historical hole collar locations were determined using three independent datasets. The primary dataset comprised CPM’s original exploration drill hole plans, which were scanned at high resolution and carefully geo-referenced to allow extraction of MGA hole coordinates. Drill collars locations were compared with drill sites identifiable from Google Earth imagery, with the same drill sites converted from CPM’s original local coordinate grid. Agreement between the three data-sets was found to be excellent and historic drillhole locations were accurately identified. After initial identification Energy Metals technicians surveyed all drill holes at the deposit as well as the ERL corner boundary pegs usingan Altus APS-3 RTK base receiver & rover(RTK |
14
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| DGPS). The precision quoted by Altus is 0.6cm in the horizontal plane and 1cm in the vertical plane. A local base station was established at a Survey Control Point via the AUSPOS system. Elevations are derived AHD heights computed using the AUSGeoid09. The centre of the drill collar was measured. The coordinates are located on the MGA94 grid, Zone 53 using the GDA94 datum (refer Annexure 2). All holes were drilled sub-vertically between -65° & -75° inclination with downhole deviation surveys undertaken in the diamond tails at 30 m to 50 m intervals. Dip and azimuth measurements were attained using a Pajari single shot tool or occasionally by acid etch. Surveys of modern drillholes were conducted using a Pathfinder multishot tool at 50 m intervals. Magnetic declination is 005° NNW and this value was applied to azimuths to convert to Grid North for modelling. Topographic control was provided by a digital terrain model (DTM) generated from radiometric and magnetic helicopter survey data flown in 2014. Since surface relief is subdued and the deposit is buried at an unconformity below 80 - 100 m of cover sequences, the topography has a negligible effect on the deposit modelling. |
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| 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. |
The Malawiri deposit was drilled on NNE (010-020°) panels spaced at 60 - 120 m. Within strongly mineralised zones infill drilling was conducted on 30 m spaced panels with 10 – 20 m step-outs (due to sub vertical body) to test down dip continuity. EME and CSA Global consider the spacing sufficient to establish continuity of geology and grade for the purposes of estimation of an inferred mineral resource. Historical downhole gamma logs were digitised at 10 cm intervals and were composited for resource reporting purposes. |
| 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. |
In general, Bigrlyi-style (tabular stratiform sandstone-hosted) uranium mineralisation, of which Malawiri is an example, exhibit no significant structural control. Mineralisation is controlled by physical and chemical characteristics of the host rock such as permeability and redox state and is influenced by primary depositional and sedimentological features. In the case of Malawiri a late oxidative overprint has affected the distribution of mineralisation. The deposit occurs in steeply dipping beds and was sampled by mostly sub-vertical drill holes. The downhole gamma probe data was subsequently corrected for mineralised zone boundary effects by deconvolution. There is therefore no bias of sampling related to orientation of the mineralised zones. |
| Sample security |
The measures taken to ensure sample security. |
Historic drill-core was geologically logged and sampled by CPM geologists and field technicians in the period 1979 and 1982. Historical core was archived at the NTGS core storage facility, Alice Springs, before being transported and securely stored at EME’s Bigrlyi core storage facility in 2006. EME geologists have verified the completeness of core materials for each hole. EME has ensured that historically sampled intervals match the lithological logs, and that core taken from those intervals, match historical sample tables, dispatches and receipts. Since 2005 EME has securely maintained a complete set of CPM documentation from this period in its archives including original gamma log traces. EME geologists managed the chain of custody of samples using well established internal procedures: sample preparation, dispatch and tracking is managed by the project geologist, the Radiation Safety Officer and database administrator. The secure transport of all samples is documented according to the company’s Radiation Management Plan. |
15
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Audits or reviews |
The results of any audits or reviews of sampling techniques and data. |
A review of gamma-ray logging reprocessing procedure was undertaken by a third party consultant. The aim was to check if there was a difference between modern and reprocessed historical gamma-ray log results using the different processing techniques. The results are in agreement with less than 1% difference in the outcomes providing a high level of confidence in the data. |
JORC 2012 Table 1 Section 2 – Key Classification Criteria
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| 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 security of the tenure held at the time of reporting along with any known impediments to obtaining a licence to operate in the area. |
Granted joint venture tenement ELR41 covers the Malawiri deposit which is a joint venture between EME (52.1%) and Northern Territory Uranium Pty Ltd (NTU: 47.9%). EME is the operator of the joint venture. ELR applications 27 to 32 adjoin ELR41 and are owned 100% by NTU; they largely cover the adjacent Minerva prospect, however a small proportion of the Malawiri resource extends on to ELR28 which is located immediately to the south of ELR41. The ELRs are embedded within surrounding EL24451 which is part of EME’s 100% owned Ngalia Regional Project. A Native Title Claim covering the Napperby pastoral lease on which the Malawiri deposit is located, was granted by consent on 2-July-2013. The Alherramp Ilewerr Mamp Arrangkey Tywerl Aboriginal Corporation is the relevant Registered Native Title Body Corporate and holds the native title interests on behalf of the traditional owners. ELR41 is covered by AAPA Authority Certificate C2014/116 issued on 29th August 2014. No significant heritage or sacred site issues were identified on ELR41. ERL41 is located on the northern margin of the Lake Lewis Site of Conservation Significance (SOCS Site No. 54). At the time of reporting there are no known impediments which could affect an application for a licence to operate in the area. |
| Exploration done by other parties |
Acknowledgment and appraisal of exploration by other parties. |
Most of the exploration data used for resource estimation purposes is the result of drilling programs undertaken by CPM over the period 1979 to 1982. EME acquired CPM’s interest in the project in 2005 including all historical data and archived drill core |
| Geology | Deposit type, geological setting and style of mineralisation. |
The Malawiri deposit is a Bigrlyi–style, tabular, stratiform, sub vertical, sandstone-hosted uranium deposit of Carboniferous age located within the Ngalia Basin in the Northern Territory. The deposit is unconformably overlain by Cenozoic cover sequences of between 80-100m thickness |
16
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Drillhole Information |
A summary of all information material to the understanding of the exploration results including a tabulation of the following information for all Material drillholes: Easting and northing of the drillhole collar Elevation or RL (Reduced Level – elevation above sea level in metres) of the drillhole collar Dip and azimuth of the hole Downhole 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. |
Refer to Annexure 1. All information relevant to hole MARD004 has previously been reported to the ASX (see announcement of 27-Sept-2016). |
| Data aggregation methods |
In reporting Exploration Results, weighting averaging techniques, maximum and/or minimum grade truncations (e.g. 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. |
Exploration results, i.e. mineralised intercepts, are reported as equivalent U3O8 values (eU3O8) from processed gamma logs. For reporting purposes (see Annexure 2) significant gamma log intersections have been composited from 10 cm deconvolved eU3O8 values using the following criteria: a cut- off grade of 100 ppm U3O8, a minimum thickness of 0.3 m, a maximum internal dilution of 0.3 m, no external dilution and a grade x thickness value of >100. |
| 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 drillhole angle is known, its nature should be reported. If it is not known and only the downhole lengths are reported, there should be a clear statement to this effect (e.g. ‘downhole length, true width not known’). |
Based on structural measurements from geological logging of drill core by CPM & EME geologists, sandstone beds hosting mineralisation are steeply dipping (broadly between 70° and 88° degrees) toward the north. All CPM & EME holes have been drilled toward the south at between -65° to - 75° and true widths of intersections are within the range 30 to 50% of the reported downhole widths. |
17
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| 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 drillhole collar locations and appropriate sectional views. |
. |
| 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. |
All significant results have been reported. Historical results have previously been reported by CPM and are available as open file reports from the NTGS. |
| 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. |
Bulk density measurements were undertaken on historical and modern core samples (see below for further details). Petrographic work was conducted by the CSIRO in 2015 and has shown a close association between uranium and detrital- origin phyllosilicate minerals including biotite, clays and chlorite. It was found that uranium minerals (uraninite) typically occur at the grain-to-grain contacts between K feldspar and quartz and as replacement of pyrite along cleavage planes within biotite and chlorite. Exposure to oxidising fluids after uranium precipitation resulted in K- feldspar dissolution, removal of uranium and precipitation of hematite. Uranium is preserved in patches where detrital grain contacts were not exposed to the late fluids and where uranium was protected within low permeable micas and clays. Measurements of Pb-isotope ratios in mineralised core from MARD004 indicate substantial disturbance of the Pb-U isotopic system likely reflecting mobility and re-distribution of U and Pb on the metre to decimetre scale within the deposit. |
| Further work | The nature and scale of planned further work (e.g. 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. |
Subject to economic conditions, future exploration activities are proposed to test for extensions of mineralisation along strike to the west and within potential stratigraphic repeats associated with adjacent folded units of the Mt Eclipse Sandstone. |
JORC 2012 Table 1 Section 3 – Key Classification Criteria
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| 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. |
Historical data used in the Mineral Resource estimate was sourced from the original hardcopy. Hardcopy data was converted to digital format and collated, tabulated and verified before being validated upon importation into EME’s Geobank database. CSA Global were provided with a validated Micromine database by EME. Relevant tables from the database were exported to Micromine .DAT format for import into Micromine 2013 software prior to use in the Mineral Resource estimation. |
18
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Validation of all imported data included checks for missing, duplicated and/or incorrectly recorded collar locations, survey data, sample data, gamma log data and lithological log data. Original historical gamma logs were reprocessed to yield eU3O8 (ppm) values which correlated well with the historical information stored in EME’s archives. |
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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 were undertaken by the Competent Person (Mineral Resource Estimation) or CSA Global staff. CSA has relied on EME for all data regarding the deposits, and given the current stage of the project, considers this appropriate. |
| 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. |
There is a reasonable level of confidence in the geological interpretation of the Malawiri deposit. Although steeply dipping, the host sandstone stratigraphy is traceable and continuity between drill holes and sections can be demonstrated. Geological controls such as the dip of the sedimentary units and the identified conglomerate and siltstone marker beds have been used to constrain the extrapolation of mineralisation within stratigraphic bounds. Geological structure and gamma logging have formed the basis for the geological interpretation. REF corrections have been determined and applied as discussed above. Further work may be required to better define the limits of the mineralisation, particularly along strike, but no significant downside changes to the currently interpreted mineralised volume are anticipated. Mineralisation is mainly hosted in partially oxidised coarse to very coarse (sometimes pebbly) arkose and arkosic sandstone. A common characteristic is that uranium mineralisation is closely associated with a late hematitic (oxidative) overprint. The hematitic mineralised zones are often carbonate rich. Grade continuity is controlled by redox zonation within the partially oxidised sandstones and siltstones. The deposit is hosted along the southern margin of the Ngalia Basin, which is a deformed, elongate intracratonic depression about 300 km long (east-west) and 40 km wide (north- south) on average. This basin is filled with late Proterozoic to Palaeozoic aged sedimentary rocks, predominantly continental-marine arkosic sandstone, and Neoproterozoic glacigene deposits and quartzite. |
| 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. |
Mineralisation is present in a series of multiply stacked lenses that are variably distributed along strike and at depth due to probable epigenetic modification. The dimensions of the Malawiri mineralised domain is approximately 400 m along- strike with an average plan width of 10-15 m and maximum modelled plan width of 35 m.. The mineralised interval varies from 0.3 m to 12.6 m, averaging 3.2 m. The model extends from the unconformity surface at approx. 80m depth to 250 m below surface. |
| 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, |
Gamma logging has been used for the definition of mineralised intervals and interpretation (wireframing) of mineralisation. The model consists of 36 mineralised domains defined by wireframe models. Grade estimation was carried out using the Multiple Indicator Kriging (MIK) method using Micromine 2013 software. Downhole and directional indicator semivariograms have been used to define the distance of interpolation. No top cut of extreme grade values was undertaken. No previous resource estimation has been undertaken for the Malawiri deposit. |
19
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| 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 (e.g. 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 drillhole data, and use of reconciliation data if available. |
No assumptions have been made regarding recovery of by- products. No other elements were estimated. The block model was constructed using a 2 m E by 0.125 m N by 2 m RL parent block size, without sub-celling for domain volume resolution. The parent cell size was chosen on the basis of the morphology of mineralised lenses and in order to avoid the generation of unrealistically large blocks. The search ellipse radii were determined from the ranges of semivariograms: the main direction being along strike of mineralised bodies (range 44 m), the second direction being down dip of mineralised bodies (range 20 m) and the range of the third direction was set at 12 m. Search ellipsoid parameters are in the table No selective mining units were assumed in this estimate. Geological boundaries were used to guide the interpretation of mineralised lenses. Specifically, mineralisation is hosted by steeply dipping (approx. 80°) Mt Eclipse Sandstone. Grade envelopes at 100 ppm U3O8 were defined for interpretative purposes. A 100 ppm U3O8 cut-off grade was applied to mineralisation inside envelopes. No top cut has been applied. Validation of the block model consisted of a comparison between the block model volume and the wireframed volumes. Grade estimates were validated by visual comparison with the drill data. Grade estimation was verified by IDW2 without a top cut applied and with a top cut of 10,000 ppm U3O8 applied. The block model compared favourably with grade composites for a series of sections in different directions (east). No reconciliation data is available at this early stage of the project. Runs Search radius Coefficient to search radius Minimum no. ofpoints Maximum no. ofpoints Minimum no. of drillholes 1 5 x 5 x 1 1 1 20 1 2 35 x 35 x 1 0.667 3 20 2 3 70 x 70 x 1 0.667 3 20 2 4 70 x 70 x 1 1 3 20 2 5 140 x 140 x 2 1 1 20 1 6 210x 210x 3 2 1 20 1 7 280 x 280 x 4 3 1 20 1 8 350 x 350 x 5 4 1 20 1 9 700 x 700 x 10 5 1 20 1 |
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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. |
The tonnages are estimated on a dry basis. |
| Cut-off parameters |
The basis of the adopted cut-off grade(s) or quality parameters applied. |
A cut-off grade of 100 ppm U3O8 (116 ppm eU3O8) has been used for interpretation and a cut-off grade of 100 ppm U3O8 has been used for resource reporting. Based on CSA’s experience with this type of deposit, this is considered a reasonable cut-off grade which could result in eventual economic extraction. |
| 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 |
At this stage of resource development it is assumed that mining would be by underground methods. Future hydrogeological investigations and leaching tests would be useful in determining whether solution mining may be possible. |
20
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| with an explanation of the basis of the mining assumptions made. |
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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. |
Metallurgical and hydrological test work is required to determine if the deposit is amenable to solution mining. There is a requirement for a certain level of natural permeability and for mineralisation to occur below the water table if in-situ recovery is to be considered. Hydrological pumping cluster tests would need to be undertaken if the deposit is found to be amenable to in-situ extraction processes. |
| 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 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. |
No detailed assumptions regarding possible waste and process residue options have been made at this early stage. |
| 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. |
Bulk density testing was carried out on both mineralised and un-mineralised drill core. The dataset comprises 146 in-house bulk density measurements of historical core from 16 holes and 38 bulk density measurements of mineralised core from hole MARD004 undertaken by ALS laboratories, Perth. The main rock types found at Malawiri are pebble conglomerate, arkose, arkosic sandstone and shale, all of which may be mineralised. Density estimates were obtained using the Archimedes method. For the in-house measurements the balance was calibrated using two standard weights. Hairspray was used to seal the exterior to account for natural porosity (voids) when necessary. Average bulk densities are as follows: pebble conglomerate: 2.48 +/- 0.07; arkose: 2.42 +/- 0.06; mineralised arkose: 2.45 +/- 0.06; arkosic sandstone 2.44 +/- 0.06; shale: 2.52 +/- 0.06 (1sd) t/m3 The average bulk density of mineralised core is 2.45 t/m3 and this value has been applied to all material in the models. |
21
| Criteria | JORC Code explanation | Commentary |
|---|---|---|
| Classification | The basis for the classification of the Mineral Resources into varying confidence categories. Whether appropriate account has been taken of all relevant factors (i.e. 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. |
CSA Global has considered several factors in the classification of the Mineral Resources such as search ellipse dimensions, geological data and exploration drill-hole grids. The Malawiri deposit has been classified as Inferred due to consideration of: exploration grid density; structural disposition of ore bodies relative to host units; variability of mineralised lenses; search ellipse dimensions relative to semi-variogram ranges; and radiochemical disequilibrium. The Inferred classification has taken into account all available geological and sampling information, and the classification level is considered appropriate. The Mineral Resource estimate appropriately reflects the views of the Competent Persons. |
| Audits or reviews |
The results of any audits or reviews of Mineral Resource estimates. |
Internal audits were completed by CSA Global which verified the technical inputs, methodology, parameters and results of the estimate. No external audit of the MRE has been undertaken |
| 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 of the Mineral Resource estimate is reflected in the reporting of the Mineral Resource as Inferred as per the guidelines contained in the 2012 JORC Code. The resource statement refers to global estimation of tonnes and grade. No production data is available for comparison. |
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