KAOLIN NOT JUST FOR INDIGESTION….
COMMERCIAL KAOLIN White (white firing) non-swelling clay - Also called “China Clay” World Production 30mtpa (US$3b) Export markets 9mtpa
USES OF KAOLIN
Commercial Economics PREMIUM GRADE CRITERIA A high priced Kaolin has : Superior Brightness Superior Whiteness Desired particle size High opacity (good hiding power) Chemical purity Low viscosity (for paper markets) Other properties - abrasivity, conductivity, etc
Pigment markets - Brightness Competitors Pigment Price per tonne (A$) TiO2 $3500 - $6000 CaCO3 $350 - $500 Kaolin $200 - $1200 Kaolin gives good performance for the price
Markets - Paper Demand Paper demand increases with GDP Asian paper production to overtake USA by 2010* Asia imports Kaolin from: Georgia Brazil UK * Source: Pulp and Paper Magazine
KAOLIN FORMATION Associated with laterite and bauxite Formed in wet/dry tropical climate Over 1500m rain pa Leaching process
LATERITIC WEATHERING
MORE EFFECTIVE LEACHING More water flow (fresh water & permeability) More time More bugs Acid groundwater (oxidising organics) - Parent is only important if time is short or leaching is slow.
REMOVAL OF IRON Ferrous leached more easily than ferric. Least iron just below lowest water table But leaching is slow below the water table Organic grey kaolins formed here.
DIAGENESIS OF KAOLIN Kaolinite increases in grain size The perfect kaolin recipe - Formed below water table then raised above it
SEDIMENTARY KAOLINS? Cannot separate kaolinite from other clays by sedimentation. All commercial kaolins are formed in situ (Pickering & Hurst 1997) Ball clays? (70% disordered kaolin).
SKARDON RIVER KAOLIN - discovery…. Andrew White in 1985 19 holes 2 in lease Target of “Bulimba” kaolin found; Older weathering kaolin noted. Samples to CSIRO
SKARDON RIVER KAOLIN - exploration history pre SRK 1987 - 1990 Bulk sampling & testwork 1993 - 188 RC holes - geology & ‘clay’ 1994 - 10 DD holes 1994 - 97 - Testing selected drill samples 1997 - 207 RC holes - poor control
MISTAKES….. No initial raw values Did not relate metallurgy to geology Poor technical knowledge at board level Rolls Royce plant Major cost over-runs No coordination of consultants/contractors
GEOLOGICAL HISTORY…..
Uplift and Weathering...
Tertiary Sheet Fluvials
Weathering to bauxite
Fluvial Channel Develops
Further Weathering…...
Claystone Mining
Conchoidal claystone
Fluvial in exploration pit
RESOURCES
Resource Summary
Skardon Kaolin Properties
Skardon Product Range Hydrous Kaolins - Plant capacity 75,000 tpa
- Wide range of industrial applications
- Represents the bulk of world supply
- Target of paint & rubber markets
Stage 1 Processing: Wet Plant
Stage 2 Processing: Dry Plant
MAJOR WORLD DEPOSITS Georgia, USA Amazon, Brazil Cornwall, UK ……….the odd one out - Hercynian granite 280mA
- Debate weathering vs hydrothermal
- Coarse grained well crystallised kaolin
- Very limited available resources
- Product yield 15-20%
Georgia - Geology Cretaceous and Tertiary bedded kaolins Cap bentonite Cretaceous 60% -2micron Tertiary 85% -2micron
Georgia - Economics ADVANTAGES Two types of kaolin Expertise Reputation Transport for E USA & Europe
Amazon Geology Under bauxite exposed on slopes. Rio Jari – Pliocene, very fine grained 75% -2 micron. 36m thick deposit. Rio Capim – also Tertiary. Coarser than Jari. Thinner and some grit.
Amazon Economics ADVANTAGES Fine Kaolin Modern plant
Summary of the Skardon River Kaolin Project Long mine life Premium products Exceedingly low CAPEX entry price Best logistics for Asia Marketing and distribution agreements Technical Management Expertise
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