CRC LEME OPEN FILE REPORT 186
A PRELIMINARY ASSESSMENT OF KAOLIN FROM BODDINGTON GOLD MINE
B Singh and R R Anand
Kaolin has a wide range of commercial applications as a pigment, coater, filler, extender, raw material for ceramics, source of Al and Si, catalyst base, electrical insulator and as an inert base in pharmaceuticals. Some of the most common uses include paper coating and filling, and as a raw material for porcelain and dinnerware. Although kaolin occurs widely, only those deposits that have critical optical properties, purity, and proximity to infrastructure can be exploited commercially.
Boddington Gold Mine (BGM) processes large volumes of kaolin in extracting gold from the weathered zone. A field examination of the white patches on the pit walls suggests BGM kaolins to be of good industrial quality. Proximity to a port, minimal exploration, mining and processing costs add to the feasibility of kaolin mining at BGM.
The aim of this preliminary study was to test a limited number of BGM kaolins for a few of the most critical characteristics to make an initial assessment of their industrial value. Five samples were taken from various pit faces of BGM. The samples were analysed for their kaolin content, mineralogical purity, brightness, and morphology.
The following conclusions are made from the study:
The BGM samples contain 50-70% kaolin, most of which (70-90%) can be separated into a <5 µ m fraction. The kaolin content is better than many commercial kaolin deposits.
There are minimal Fe- and Ti-oxides impurities in the <5 µ m fraction of most samples. Most of the quartz is coarser than 5 µ m and can be separated by a low-cost sedimentation process.
The brightness of untreated BGM kaolins is comparable with the brightness of operating kaolin deposits, and is acceptable for use in ceramics and as a filler in paper, paint, and plastics without beneficiation.
A paper coating-grade product may be produced from BGM kaolins using appropriate beneficiation processes common in the kaolin industry.
The brightness of calcined BGM kaolins is remarkably high, and matches that of calcined products of beneficiated kaolins from other deposits. It is expected that calcination of BGM kaolins, after appropriate beneficiation, would result in exceptionally high brightnesses.
Both halloysite and kaolinite-type kaolins can be produced from the BGM deposit.