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Sydney, May 8, 2012 (ABN Newswire) - Emerging bauxite exploration and development company, Australian Bauxite Limited (
ASX:ABZ) discovered a thick layer of good quality bauxite in 2008-09 at its Inverell project in northern NSW (see Figure 1). Parts of that bauxite lie beneath a clay horizon and required further investigation. ABx conducts thorough evaluation programmes and results from 37 new holes into the concealed bauxite are generally consistent with previous Inferred resource estimates for those zones.
A rigorous selection of the bauxite intercept thicknesses and grades has been applied so that the grades of the resources better reflect the nature of the deposit, with A/S ratios increasing from 6.7 to 8.5 and Al2O3 increasing from 37.8% to 40.2%.
The Inverell deposit lies near the top of a plateau north of the city of Inverell, which has been widely cleared for farming and grazing.
The bauxite in the resource area is consistently medium quality, low silica gibbsite bauxite suitable for low temperature bauxite-alumina refineries.
New areas of bauxite in the Inverell-Stannifer-Guyra area of northern NSW have been discovered in recent months and are currently being explored to expand resource extent and to identify resource drilling targets.
Logistical Setting
The Inverell bauxite project is located approximately 430kms inland from Newcastle port and is not serviced by a heavy duty rail line. Therefore, this bauxite project is not considered a candidate for early development for direct export. However Inverell may form part of a sizeable bauxite province in northern NSW that has potential to justify a bauxite processing facility, possibly even a new bauxite-alumina refinery.
Further Work Planned
The bauxite deposit is open in many locations and many other deposits have been identified. New tenements containing high-grade bauxite outcrops have been secured in the region, especially at Stannifer halfway between Inverell and Guyra. These will be the next areas evaluated in northern NSW.
RESOURCE ESTIMATE METHOD
Reconnaissance and follow-up exploration drilling was done on a semi-random but systematic pattern governed by site availability across Inverell EL 6997 to test several of the many bauxite targets. By 30 November 2011, 233 holes had intersected a moderate quality bauxite layer, concealed in many places beneath a surface clay and soil layer 1 to 3 metres thick.
Drill samples were collected at 1 metre intervals from the aircore drillholes and analysed at ALS Laboratories in Brisbane including trihydrate (THA) available alumina ("Al2O3 Avl") and reactive silica ("Rx SiO2") measurements. Leach conditions to measure available alumina "Al2O3 Avl" and reactive silica "Rx SiO2" were 1g leached in 10ml of 90gpl NaOH at 143 degrees C for 30 minutes.
Estimation was done by geostatistical block modelling of bauxite intercepts, constrained within geological boundaries using Gemcom resource estimation software. The block size is 25m x 25m and drill spacing within the bauxite zones was typically at 75 to 150 metres spacings. Data interpolation of up to 350 metres was done, based on statistical assessments of continuity.
A tight boundary was drawn around bauxite intercepts in the new areas and the resources within these new areas were classified as Indicated because of the close-spaced drilling inside those boundaries. No Inferred Boundary has been drawn because of the high proportion of concealment. In the areas drilled in the past, blocks with less than 6 datapoints within that 350 metre search ellipse were classified as Inferred Resources and the more heavily drilled blocks were classified as Indicated Resources.
Bauxite density was conservatively assumed at 1.85 dry tonnes per cubic metre in situ even though this bauxite layer is generally unweathered due to protection from the overlying clay layer.
To view the full announcement including charts and tables, please visit:
http://media.abnnewswire.net/media/en/docs/ASX-ABZ-677907.pdf
ASX:ABZ) discovered a thick layer of good quality bauxite in 2008-09 at its Inverell project in northern NSW (see Figure 1). Parts of that bauxite lie beneath a clay horizon and required further investigation. ABx conducts thorough evaluation programmes and results from 37 new holes into the concealed bauxite are generally consistent with previous Inferred resource estimates for those zones. A rigorous selection of the bauxite intercept thicknesses and grades has been applied so that the grades of the resources better reflect the nature of the deposit, with A/S ratios increasing from 6.7 to 8.5 and Al2O3 increasing from 37.8% to 40.2%.
The Inverell deposit lies near the top of a plateau north of the city of Inverell, which has been widely cleared for farming and grazing.
The bauxite in the resource area is consistently medium quality, low silica gibbsite bauxite suitable for low temperature bauxite-alumina refineries.
New areas of bauxite in the Inverell-Stannifer-Guyra area of northern NSW have been discovered in recent months and are currently being explored to expand resource extent and to identify resource drilling targets.
Logistical Setting
The Inverell bauxite project is located approximately 430kms inland from Newcastle port and is not serviced by a heavy duty rail line. Therefore, this bauxite project is not considered a candidate for early development for direct export. However Inverell may form part of a sizeable bauxite province in northern NSW that has potential to justify a bauxite processing facility, possibly even a new bauxite-alumina refinery.
Further Work Planned
The bauxite deposit is open in many locations and many other deposits have been identified. New tenements containing high-grade bauxite outcrops have been secured in the region, especially at Stannifer halfway between Inverell and Guyra. These will be the next areas evaluated in northern NSW.
RESOURCE ESTIMATE METHOD
Reconnaissance and follow-up exploration drilling was done on a semi-random but systematic pattern governed by site availability across Inverell EL 6997 to test several of the many bauxite targets. By 30 November 2011, 233 holes had intersected a moderate quality bauxite layer, concealed in many places beneath a surface clay and soil layer 1 to 3 metres thick.
Drill samples were collected at 1 metre intervals from the aircore drillholes and analysed at ALS Laboratories in Brisbane including trihydrate (THA) available alumina ("Al2O3 Avl") and reactive silica ("Rx SiO2") measurements. Leach conditions to measure available alumina "Al2O3 Avl" and reactive silica "Rx SiO2" were 1g leached in 10ml of 90gpl NaOH at 143 degrees C for 30 minutes.
Estimation was done by geostatistical block modelling of bauxite intercepts, constrained within geological boundaries using Gemcom resource estimation software. The block size is 25m x 25m and drill spacing within the bauxite zones was typically at 75 to 150 metres spacings. Data interpolation of up to 350 metres was done, based on statistical assessments of continuity.
A tight boundary was drawn around bauxite intercepts in the new areas and the resources within these new areas were classified as Indicated because of the close-spaced drilling inside those boundaries. No Inferred Boundary has been drawn because of the high proportion of concealment. In the areas drilled in the past, blocks with less than 6 datapoints within that 350 metre search ellipse were classified as Inferred Resources and the more heavily drilled blocks were classified as Indicated Resources.
Bauxite density was conservatively assumed at 1.85 dry tonnes per cubic metre in situ even though this bauxite layer is generally unweathered due to protection from the overlying clay layer.
To view the full announcement including charts and tables, please visit:
http://media.abnnewswire.net/media/en/docs/ASX-ABZ-677907.pdf
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About Australian Bauxite Limited
Australian Bauxite Limited (ABx) (ASX:ABZ) holds the core of the newly discovered Eastern Australian Bauxite Province. Its 37 bauxite tenements in Queensland, NSW and Tasmania covering 8,500 km2 were rigorously selected on 3 principles: 1. good quality bauxite; 2. proximity to infrastructure connected to export ports; and, 3. free of socio-environmental or native title land constraints.
All tenements are 100% owned and free of obligations for processing and third-party royalties. ABx has already discovered many bauxite deposits and new discoveries are still being made as knowledge and expertise grows.
The company's bauxite is high quality and can be processed into alumina at low temperature – the type that is in short-supply globally. Global resources declared to date are 68 million tonnes. At the company's first drilling prospect in Inverell, northern NSW, an interim resource of 35 million tonnes has been reported from drilling 15% to 20% of the area prospective for bauxite and a resource of 25 million tonnes of bauxite has been reported at the Taralga project in southern NSW. 6 million tonnes maiden resource was declared at Guyra. Results from the Binjour Plateau in central QLD confirm that ABx has discovered a significant bauxite deposit including some bauxite of outstandingly high quality. Australian Bauxite Limited aspires to identify large bauxite resources in the Eastern Australian Bauxite Province which is emerging as one of the world's best bauxite provinces.
ABx has the potential to create significant bauxite developments in three states - Queensland, New South Wales and Tasmania. Its bauxite deposits are favourably located for direct shipping of bauxite to both local and export customers.
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