Inverell Resource Grade Improvement - 38 Million Tonnes Resource
Sydney, May 8, 2012 AEST (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
About ABx Group Limited
ABx Group Limited (ABx) (ASX:ABX) started as a bauxite miner in Tasmania in 2014 & controls the Eastern Australian Bauxite Province. In 2020 to 2023, ABx also discovered Australia’s only true ionic adsorption clay Rare Earth Elements resource at Deep Leads in pine plantations 40km west of Launceston with a JORC-compliant resource of 89 million tonnes from only 29% of the mineralised outline, averaging 844 ppm total rare earth oxides that is the most enriched in the critically important rare earths, Dy and Tb, of any Australian REE deposit.
ABx has also developed a proprietary technology to produce fluorine chemicals from an aluminium smelter waste product and return the fluorine back into the smelters, thus reducing reliance on imported aluminium fluoride.
ABx has committed a large proportion of its expenditure into Research and Development and has found ways to capitalise on the main strengths of its bauxite type which is very clean, free of all deleterious elements and can be separated into different product streams using physical, chemical and geophysical methods. It has produced and marketed specialist bauxite products for the manufacturers of fertiliser, cement with high late strength for major infrastructure such as bridges and is in the advanced stages of approvals for production of metallurgical bauxite from its Binjour Bauxite deposit with JORC-compliant resources of 37 million tonnes of bauxite, in a joint development with a Chinese-focussed Australian trading company Good Importing International.
ABx is also preparing to produce fertiliser grade and cement grade bauxite from its DL130 bauxite quarry in northern Tasmania, 40km west of Launceston. This quarry is sited in the middle of the large Deep Leads REE deposit and may one day be a site for heap leaching of the REE using a low-cost, benign leachate with the same acidity as apple juice or tea.
ABx endorses best practices on agricultural land, strives to leave land and environment better than we find it. We only operate where welcomed.
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