Authors / CoAuthors
Owen, H.B.
Abstract
Pisolitic bauxite containing between 40 and 50 per cent available alumina was discovered on islands off the north-east coast of Arnhem Land in 1949, and after preliminary reconnaissance in 1951 a thorough exploration of the deposits on Marchinbar Island, Wessel group was undertaken by the Australian Aluminium Production Commission. The island is composed of a gently titled alternating sequence of sandstone, siltstone and shale of upper Proterozoic age bearing remnants of a lateritized surface which includes the bauxite occurrences. Bauxite has developed by lateritization of a sericite-quartz siltstone containing rather more than 50 per cent sericite. The rock contains 65 per cent total silica, 19 per cent alumina and 6 per cent potash. Economic bauxite is mainly confined to the Pisolitic zone which has a maximum depth of 16.5 feet and rests upon red or red and black tubular and massive laterite. Over limited areas high alumina values persist downwards into the red tubular zone for a few feet. The deposits were proved by sampling pits sunk at intersections of rectangular grids spaced at 400 feet by 200 feet, except for one deposit (Fox), which was tested on a wider scale. Proved reserves are given in the following table, but the figures for Fox deposits are of a lower order of accuracy and should be regarded as indicated reserves. [See record for full details]. The total is equivalent to 4,500,000 tons of available alumina or 2,380,000 tons of aluminium metal.
Product Type
document
eCat Id
9258
Contact for the resource
Custodian
Owner
Custodian
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GA PublicationRecord
- ( Theme )
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- mineral deposits
- ( Theme )
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- geology
- ( Theme )
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- resource assessment
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- AU-NT
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1953-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Record 1953/039
Lineage
Legacy product, lineage not available
Parent Information
Extents
[-12.5, -10.5, 135.5, 137.0]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Legacy product, source data not available.