Melbourne, July 8, 2008 AEST (ABN Newswire) - The board of A-Cap Resources Limited (ASX:ACB) is delighted to advise of an updated Inferred Resource estimate based on recent drilling at its Letlhakane Project in north east Botswana.
The updated resource at a cut off grade of 100ppm comprises 280 Million tonnes at a grade of 158ppm U3O8 for 98 million pounds of U3O8 (44,500 tonnes). Mineralisation at Letlhakane remains open along strike and drilling will continue during 2008.
The new resource, prepared in compliance with the JORC Code, covers approximately 9km by 3km to a maximum depth of 70m and has been calculated by SRK Consulting as part of the Letlhakane Project scoping study. The scoping study is now anticipated to be finalised in the 3rd quarter 2008.
HIGHLIGHTS
- At a cut off grade of 100ppm the Inferred Mineral Resource is estimated at 280 million tonnes of ore at a grade of 158ppm of U3O8 for a contained 44,500 tonnes of U3O8 (98 million lbs U3O8 )
- These figures represent an 330% increase in tonnes and an 13 % increase in grade leading to an 390% increase in contained metal at the same cut-off (100ppm) when compared to the previous resource estimate.
- The Letlhakane Global Inferred Resource at a range of cut off grades is presented in the following table.
-------------------------------------------------------Cut off Contained Av grade Contained Contained U3O8U3O8 Tonnes (M) U3O8ppm U3O8 Tonnes lbs (Millions)-------------------------------------------------------100 280 158 44,690 98125 231 166 38,380 85150 140 184 25,720 57175 71 204 14,560 32200 31 228 7,110 16225 14 249 3,410 8250 5 277 1,290 3-------------------------------------------------------
- Significant areas of the resource remain open along strike and regional diamond drilling has confirmed the presence of similar styles of mineralisation up to 10km outside the boundary of the resource.
Geology
As part of Letlhakane Scoping Study a detailed review of the Geology and the threedimensional (3D) spatial distribution of mineralisation was completed.
Regionally the deposit occurs within the basal units of the Karoo Supergroup (Ecca Group) immediately above a major regional unconformity between the Karoo and the underlying Proterozoic Limpopo Mobile Belt.
In this area the sedimentary rocks of the Karoo Supergroup dip gently (<5*) towards the west and comprises a broadly upward fining fluviatile sedimentary sequence.
Mineralisation
Three different styles of mineralisation have been noted in the Mokobaesi, Gorgon and Kraken prospect areas. These are calcrete hosted secondary mineralisation, Karoo hosted secondary - oxide mineralisation and Karoo hosted primary mineralisation.
Calcrete Hosted Secondary Mineralisation:
The calcrete hosted mineralisation was previously identified by earlier explorers and, given its widespread surface exposure in the Mokobaesi area, constituted the initial exploration target. This mineralisation style is limited to the occurrence of calcrete in the immediate Mokobaesi area. The calcrete occurs as nodules, coatings on Karoo sediment fragments and as fracture fill. It is predominantly within the first two metres of the Karoo but can extend up into the base of the unconsolidated sand and clay that now cover the Karoo.
The calcrete hosted uranium mineralisation is all secondary in nature and is composed entirely of canary yellow uranium vanadates which have precipitated on the outside of the calcrete nodules and within fractures.
Karoo Hosted Secondary Mineralisation:
The Karoo secondary uranium mineralisation occurs in fractures and coating bedding planes within the finer mudstone/shale. There is also a spatial correlation between uranium mineralisation and iron oxides (haematitic horizons) in the upper profiles.
As with the calcrete mineralisation the bulk of the uranium occurs in uranium vanadates such as Carnotitie and Francevellite.
Primary Karoo Hosted Mineralisation:
Examples of primary uranium mineralisation have been noted in drill core returned from the Mokobaesi, Kraken and Gorgon prospects. Primary mineralisation is broadly strata bound within fine-grained sandstones and mudstones and often in close proximity to carbonaceous units. Uranium mineralogy is typically dominated by coffinite and uraninite.
INFERRED RESOURCE
The Board of A-Cap Resources is pleased to announce the Inferred Mineral Resource from the Mokobaesi, Kraken and Gorgon prospects which form part of the larger Letlhakane Project in North Eastern Botswana.
-------------------------------------------------------Cut off Contained Av grade Contained Contained U3O8U3O8 Tonnes (M) U3O8ppm U3O8 Tonnes lbs (Millions)-------------------------------------------------------100 280 158 44,686 98125 231 166 38,377 85150 140 184 25,718 57175 71 204 14,557 32200 31 228 7,112 16225 14 249 3,412 8250 5 277 1,286 3-------------------------------------------------------
Table 1 shows the Global Inferred Mineral Resource estimates at a range of cut off grades.
The numbers in this table are rounded to reflect the accuracy of estimates and as a consequence exhibit rounding errors. Both Contained Tonnes U3O8 and Contained Pounds U3O8 are based on contained metal in the ground and do not consider any mining, metallurgical or economic parameters at this stage.
The resource calculation is based on 1,390 Reverse Circulation (RC) and 48 diamond holes drilled by A-Cap during 2006 -2008 and includes assays for 18,312 one meter samples as well as radiometric logging data for each hole. The Mokobaesi and Kraken areas are drilled out on a 200m (east-west) by 50m (north-south) grid with minor infilling to 50m by 50m spacing. The Gorgon prospect is drilled to 200m by 200m with limited infill at closer spacing. Figures 2 and 3 show the collar locations of all holes used in the Resource calculations.
Using information collected from the drill hole logging important geological features were wireframed to create robust 3D geological models, the following surfaces were constructed:
Topography, Top of Calcrete, Base of Calcrete, Base of Oxidation, Base of Karoo and the principal bounding faults. Complementing these geological domains the ore horizons were wireframed into 100ppm, 150ppm and 200ppm grade shells
Resources were estimated from an Ordinary Kriged (OK) model generated from a stratigraphic block model. The model used two metre downhole composites of the U3O8 grades obtained from the radiometric logging data. Statistical comparisons between chemical assays and down-hole radiometrics revealed a positive bias in the probe data. Consequently the probe results were multiplied by 0.85 to address this issue, additionally an upper cut of 800ppm was used on all data. The model was constrained within the 100ppm grade shell and separate estimates were made for three different geological domains created during the 3D modelling:
1. Mokobaesi -calcretemineralisation
2. Oxide mineralisation
3. Primary mineralisation
The Inferred Resource figures for all these domains are presented below.
LETLHAKANE (MOKOBAESI) INFERRED CALCRETE RESOURCE
-------------------------------------------------------Cut off Contained Av grade Contained Contained U3O8U3O8 Tonnes (M) U3O8ppm U3O8 Tonnes lbs (Millions)-------------------------------------------------------100 9 171 1,560 3125 8 176 1,410 3150 5 187 1,020 2175 3 207 530 1200 1 233 280 1225 1 266 140 <1250 0 305 90 <1-------------------------------------------------------
LETLHAKANE INFERRED SECONDARY REOURCE
-------------------------------------------------------Cut off Contained Av grade Contained Contained U3O8U3O8 Tonnes (M) U3O8ppm U3O8 Tonnes lbs (Millions)-------------------------------------------------------100 96 162 15,480 34125 78 172 13,490 30150 53 188 9,910 22175 31 207 6,380 14200 15 228 3,460 8225 7 247 1,780 4250 2 268 670 1-------------------------------------------------------
LETLHAKANE INFERRED PRIMARY RESOURCE
-------------------------------------------------------Cut off Contained Av grade Contained Contained U3O8U3O8 Tonnes (M) U3O8ppm U3O8 Tonnes lbs (Millions)-------------------------------------------------------100 179 154 27,520 61125 150 161 24,120 53150 84 180 15,240 34175 40 201 7,950 18200 16 226 3,510 8225 6 248 1,530 3250 2 277 530 1-------------------------------------------------------
The total of these three domains give the Global Inferred Resource.
The numbers in all resource tables in this report are rounded to reflect the accuracy of estimates and as a consequence exhibit rounding errors. Both Contained Tonnes U3O8 and Contained Pounds U3O8 are based on contained metal in the ground and do not consider any mining, metallurgical or economic parameters at this stage.
Further Resource Work
Further work has been suggested by consultants at SRK to improve the robustness of the current Inferred resource and progress towards estimation of Indicated resources.
1. Increased diamond drilling across the prospect to develop a better understanding on the controls and distribution of mineralisation.
2. Extra diamond holes twinned adjacent to RC holes to examine the potential for bias between the chemical assays and radiometric logging and as a check on the RC sampling methods.
3. Close the spacing of drilling in the Gorgon area to improve confidence in the continuity of mineralisation.
4. Collection of further bulk density data to increase accuracy of estimation of tonnes across the deposit.
Scope To Grow
The Inferred Resource documented in this release and reported in compliance with the JORC code is an exciting milestone A-Cap's quest to become Botswana's first uranium producer.
However, the Board of A-CAP believe that these estimates are only the early stages of discovery of a potentially much largermineralised field. For example:
1. Regional diamond drill holes up to 10km outside the current resource area reflect the potential for further resource increases with more exploration.
2. Recently the company has commenced drilling at the Serule prospect (near Serule Village) and will be announcing results from this new area over the coming weeks.
In light of the current resource upgrade the Exploration team in Botswana will be revaluating the potential of the field and will update the Exploration Target in the coming months.
Future Exploration
Exploration drilling will continue on the Letlhakane project over the coming months. The initial focus is the Serule area some 10km south of the current resource. Drilling for extensions on the current resource is also being planned and should commence in the third quarter 2008.
Scoping Study
The new Inferred Resource statement was developed as an integral part of the scoping study. With the resource work now complete, the focus of the scoping study will turn to the completion of the metallurgical testwork. Based on the Inferred Resource and metallurgical results the scoping study will progress to initial design of open pits and process options culminating in preliminary financial modelling. It is expected the results of the scoping study will be available to themarkets in the third quarter 2008.
About A-Cap Resources Limited
A-Cap holds six prospecting licences covering a total area of over 4,400km2 and three licences under application covering a further 3,000km2. All of the ground held by A-Cap has been previously explored by major companies such as Falconbridge, BCL, Urangesellchaft and Union. All of A-Cap’s tenements have significant radiometric anomalies and indications of Uranium mineralisation exposed at surface. Significant discoveries have been made at the Letlhakane Project resulting in an Inferred Resource of 30 Million lb Uranium (at an 80ppm cut-off) that has been defined in accordance with the JORC code.
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