Australian Bauxite Limited (ASX:ABZ) Taralga Bauxite Resource Doubled To 25 Million Tonnes
Sydney, May 12, 2011 AEST (ABN Newswire) - Australian Bauxite Limited (
ASX:ABZ) has 33 bauxite tenements in eastern Australia covering more than 7,500 km2.
To clarify the marketability of the bauxite types found in the Taralga-Goulburn-Crookwell area in southern NSW, detailed drilling was recently conducted at spacings of approximately 100 metres in areas containing easily mined bauxite zones of Direct Shipping Ore ("DSO") grades because Taralga is located near a major railway line leading directly to Port Kembla export terminal.
Two main bauxite types are recognised at Taralga as shown in Figure 1 (see link at the bottom of the release), namely:
1. Gibbsite rich, low silica bauxite that will be the main component of direct shipping ore (DSO);
2. Pisolitic, dehydrated hardcap bauxite, often forming a surface hardcap layer 2 metres thick .
Each bauxite type can have quartz-rich zones where quartz grains have mixed with the bauxite.
Resources at Taralga based on drilling to date can be summarised as follows (see link at the bottom of the release):
This DSO gibbsite ore is considered to be the main type of bauxite in the Goulburn-Taralga-Crookwell district.
2. 10 million Tonnes of Pisolite Ore
In many locations, there is a 2 metre thick surface layer of "Pisolite Ore" above the main gibbsite bauxite.
This is pisolitic (rounded gravels), iron-enriched, dehydrated bauxite which is cemented into a hardcap layer in places.
Note that this material has elevated levels of iron (Fe2O3) and low loss-on-ignition (LOI) which indicates dehydration. Note also that 15% of the alumina (Al2O3) does not report as available Al2O3 at the leach temperatures used here. At moderately higher leach temperatures, it is expected that more of the total alumina would report as being available Al2O3. This will be tested as part of metallurgical testwork scheduled for June-July.
3. 5 million Tonnes of Quartz-Bearing Bauxite
At depth and laterally, both major bauxite types can become quartz-bearing bauxite in the form of sand grains and small layers of quartz-rich gravels mixed with bauxite. In places, this material is peripheral to the main deposits.
The major bauxite deposits in the Darling Ranges bauxite-alumina projects south of Perth, Western Australia are quartz-bearing and there are many similarities between the bauxites of the Eastern Australian Bauxite Province and the WA Darling Ranges bauxites.
Quartz is an inert, non-reactive form of silica (SiO2) which does not affect the processing of the bauxite into alumina and aluminium. However, it does dilute the grades of the bauxite as shown by the following tables (see link at the bottom of the release).
Note that total silica (SiO2) is approximately 20% in these bauxites, but only 1.9% to 3.1% is reactive silica.
RESOURCE ESTIMATE METHOD
Drilling on a random pattern governed by site availability was done predominantly in the northeastern parts of EL 7357 where bauxite plateaus were obvious and some in the southwestern parts of EL 7357 where unexpectedly thick, good quality bauxite was discovered in late 2010.
During August 2010, 98 holes were drilled totalling 710 metres and during September-October 2010, a further 112 holes were drilled totalling 985 metres. Infill drilling done during the first Quarter of 2011 brought the total drilling at Taralga to 577 drillholes totalling 4,575 metres drilled.
Drill samples were collected at 1 metre intervals from the aircore drillholes and analysed at ALS Laboratories in Brisbane including trihydrate (THA) available alumina (Avl Al2O3) and reactive silica (SiO2 Rx) measurements. Leach conditions to measure available Avl Al2O3 and reactive SiO2 Rx were 1g leached in 10ml of 90gpl NaOH at 143 degrees C for 30 minutes Estimation of grades and thicknesses was done by an inverse distance squared modelling method using maximum extrapolations of 100 metres for Indicated Resources category and 150 metres for Inferred Resources. Bauxite density was conservatively assumed at 1.8 dry tonnes per cubic metre in-situ.
For the complete Australian Bauxite Limited announcement including figures and tables, please refer to the following link:
http://www.abnnewswire.net/media/en/docs/634237.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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