Dawson-Hinkler Well
(U3O8 Limited 100%)
-
JORC Compliant Report of Inferred Mineral Resource of 10 million pounds U3O8
Dawson-Hinkler Well is located in the most prospective area in the world for calcrete hosted uranium deposits, situated 40 kilometres north of BHP Billiton's Yeelirrie uranium deposit, the world's largest calcrete hosted deposit (50,000 tonnes of contained U3O8) and 10 kilometres west, and along the same calcrete channel, from Nova Energy Limited's Lake Way-Centipede uranium deposits (Inferred Resource 15.5 million tonnes at 580ppm U3O8). Mega Uranium's Lake Maitland deposit is located 70 kilometres to the south-east (Inferred Resource 32.7 million tonnes @ 330 ppm U3O8).
During October and November 2006, U3O8 Limited undertook a detailed reverse circulation drilling programme on the Dawson-Hinkler Well project. As a follow up to the drilling completed and reported on in the 2006 annual report, the Company drilled four prospects within the Dawson-Hinkler Well project (Dawson West, Dawson East, Hinkler West, Hinkler) in detail, to enable the calculation fo a JORC-compliant resource estimate.
In all 419 reverse circulation drill holes were completed on the four prospects for a total advance of 5406 metres. The table below details the programme.
Following receipt of all drilling data, U3O8 Limited contracted consultant group Hellman & Schofield Pty Ltd to perform the resource estimation of the Dawson-Hinkler Well deposit. The resource estimation is based on both the historical drilling and the two reverse circulation drilling programmes completed by the Company in 2006.
Wire framing of the mineralisation was undertaken in MICROMINE using a 100ppm U3O8 cut-off grade for intervals in excess of 0.2m. This was used to exclude irrelevant samples beneath the main body of mineralisation.
Duplicate radiometric logging of a selection of holes (approximately 1 in 20) and repeat logging of a reference hole (once a day) all indicate that radiometric logging is of a high quality and that data compares within acceptable and expected variation. Corrections for hole diameter and water was conducted on all drilling undertaken by U3O8 Limited. A number of early holes drilled by Western Mining were assumed entirely dry and no water correction for gamma absorption had been conducted at the time of logging. A slight low bias in measured U3O8 at deeper levels on some WMC holes is evident when compared with appropriately corrected data. The impact on the resource is not significant.
Results of the resource estimation were reported using cut-off grades between 100 and 300 ppm U3O8. Estimates were generated using the method of Ordinary Kriging (OK) of uranium grades based on downhole radiometric data.
The table below summarises the resource estimate at the various grades used.
Inferred Resources Dawson-Hinkler
There remains potential at Dawson-Hinkler to increase the resource by completion of further drilling. An additional drilling programme has been planned for the 2007/8 year.
During October and November 2006, U3O8 Limited undertook a detailed reverse circulation drilling programme on the Dawson-Hinkler Well project. As a follow up to the drilling completed and reported on in the 2006 annual report, the Company drilled four prospects within the Dawson-Hinkler Well project (Dawson West, Dawson East, Hinkler West, Hinkler) in detail, to enable the calculation fo a JORC-compliant resource estimate.
In all 419 reverse circulation drill holes were completed on the four prospects for a total advance of 5406 metres. The table below details the programme.
| Project area | Number of holes | Metres | Drill spacing of this programme | Final drill spacing of project area |
| Dawson West | 121 | 1,780 | 400 x 100 m | 200 x 100 m |
| Dawson East | 89 | 952 | 400 x 100 m | 400 x 100 m |
| Hinkler West | 106 | 1,369 | 400 x 100 m | 400 x 100 m |
| Hinkler | 103 | 1,305 | 400 x 100 m | 400 x 100 m 200 x 100 m |
A summary of the most significant drill intersections from this programme has been included in the table below.
Significant intersections from Dawson-Hinkler Well Project reverse circulation drilling
Drill holes were located by high resolution differential GPS. Drill chip recovery is extremely variable, reflecting typically difficult drilling conditions of the calcrete sheets. The definition of eU3O8 can be found under the Wabli Creek project section.
Sampling and chemical assay of reverse circulation drill cuttings was conducted on 1183, 0.5m intervals for the purpose of radiometric grade validation. This represents a checking rate of approximately 10% of composited intervals. Duplicates consisted only of laboratory routine duplications after sample preparation.
| Prospect | Hole | Easting | Northing | From | To | Thickness (m) | eU3O8 (ppm) |
| DAWSON WEST | RCDW167 RCDW168 RCDW169 RCDW170 RCDW171 RCDW172 RCDW176 RCDW177 RCDW181 RCDW191 RCDW192 RCDW200 RCDW216 RCDW217 RCDW218 RCDW225 RCDW226 RCDW227 RCDW228 RCDW236 RCDW237 RCDW238 RCDW239 RCDW240 RCDW241 RCDW248 RCDW249 RCDW251 RCDW252 RCDW253 |
208818 208846 208886 208918 208957 209001 209085 209148 209295 209494 209553 209682 209963 209917 209869 210003 210048 210105 210163 210189 210245 210292 210336 210388 210493 210512 210555 210631 210682 210717 |
7018696 7018594 7018518 7018436 7018354 7018271 7019056 7018968 7018621 7019047 7018963 7019213 7019044 7019130 7019209 7019319 7019234 7019158 7019070 7019367 7019293 7019206 7019119 7019037 7018943 7019706 7019624 7019446 7019353 7019268 |
5.09 7.15 4.36 3.95 3.59 4.26 5.52 5.40 6.65 4.49 6.44 6.75 6.99 6.88 7.31 6.88 7.72 7.14 6.39 5.94 4.68 7.6 6.9 5.4 6.02 5.77 4.28 6.64 6 6.77 6.91 6.37 |
6.65 8.51 6.04 6.81 6.19 7.46 7.18 6.96 10.15 5.85 8.94 10.15 7.93 9.36 10.81 9.02 10.36 8.26 8.21 7.96 6.06 11.70 10.52 6.66 7.52 7.01 5.12 7.92 6.92 8.83 8.39 7.25 |
1.56 1.36 1.68 2.86 2.60 3.20 1.66 1.56 3.50 1.36 2.50 3.40 0.94 2.48 3.50 2.14 2.64 1.12 1.82 2.02 1.38 4.10 3.62 1.26 1.50 1.24 0.84 1.28 0.92 2.06 1.48 0.88 |
290.2 303.7 319.6 336.1 371.6 324.8 330.1 339.2 282.6 389.7 429.4 378.8 441.8 388.4 448.6 367.2 377.5 389.8 298.4 378.9 436.1 366.8 534.7 443.8 622.6 588.2 530.8 560.9 512.2 532.2 562.1 585.6 |
| DAWSON EAST | RCDW341 RCDW342 |
214388 214285 |
7020542 and 7020744 and |
1.54 6.48 3.89 5.65 |
3.62 8.26 5.09 6.97 |
2.08 1.78 1.20 1.32 |
286.5 342.0 390.2 344.4 |
| HINKLER WEST | RCDW360 RCDW362 RCDW371 |
217073 216962 217277 |
7022389 7022648 7022965 |
0.03 3.10 3.78 |
1.47 4.72 5.14 |
1.44 1.62 1.36 |
738.2 306.6 294.8 |
| HINKLER | RCDW449 RCDW461 RCDW494 RCDW552 |
219616 220092 220925 222083 |
7023637 7023863 7024515 7024003 |
4.43 3.44 3.42 0.50 |
5.61 4.74 5.00 1.84 |
1.18 1.30 1.58 1.34 |
424.4 471.2 576.1 557.2 |
Significant intersections from Dawson-Hinkler Well Project reverse circulation drilling
Drill holes were located by high resolution differential GPS. Drill chip recovery is extremely variable, reflecting typically difficult drilling conditions of the calcrete sheets. The definition of eU3O8 can be found under the Wabli Creek project section.
Sampling and chemical assay of reverse circulation drill cuttings was conducted on 1183, 0.5m intervals for the purpose of radiometric grade validation. This represents a checking rate of approximately 10% of composited intervals. Duplicates consisted only of laboratory routine duplications after sample preparation.
Following receipt of all drilling data, U3O8 Limited contracted consultant group Hellman & Schofield Pty Ltd to perform the resource estimation of the Dawson-Hinkler Well deposit. The resource estimation is based on both the historical drilling and the two reverse circulation drilling programmes completed by the Company in 2006.
Wire framing of the mineralisation was undertaken in MICROMINE using a 100ppm U3O8 cut-off grade for intervals in excess of 0.2m. This was used to exclude irrelevant samples beneath the main body of mineralisation.
Duplicate radiometric logging of a selection of holes (approximately 1 in 20) and repeat logging of a reference hole (once a day) all indicate that radiometric logging is of a high quality and that data compares within acceptable and expected variation. Corrections for hole diameter and water was conducted on all drilling undertaken by U3O8 Limited. A number of early holes drilled by Western Mining were assumed entirely dry and no water correction for gamma absorption had been conducted at the time of logging. A slight low bias in measured U3O8 at deeper levels on some WMC holes is evident when compared with appropriately corrected data. The impact on the resource is not significant.
Results of the resource estimation were reported using cut-off grades between 100 and 300 ppm U3O8. Estimates were generated using the method of Ordinary Kriging (OK) of uranium grades based on downhole radiometric data.
The table below summarises the resource estimate at the various grades used.
| Cutoff Grade (ppm U3O8) |
Grade (ppm U3O8) |
Tonnes (millions) |
U3O8 (tonnes) |
U3O8 (million lbs) |
| 100 | 163 | 51.5 | 8,400 | 18.5 |
| 150 | 228 | 20.7 | 4,700 | 10.4 |
| 200 | 293 | 9.5 | 2,800 | 6.2 |
| 250 | 341 | 5.6 | 1,900 | 4.2 |
| 300 | 383 | 3.5 | 1,300 | 2.9 |
Inferred Resources Dawson-Hinkler
There remains potential at Dawson-Hinkler to increase the resource by completion of further drilling. An additional drilling programme has been planned for the 2007/8 year.