KAOLIN NOT JUST FOR INDIGESTION…. Sue Border
COMMERCIAL KAOLIN • White (white firing) non-swelling clay- Also called “China Clay” • Dominantly kaolinite • World Production 30mtpa (US$3b) • Export markets 9mtpa
USES OF KAOLIN • Papermaking Pigment/Filler/Coating • Pigment in paint/inks High • Plastics/Rubber Value • Ceramics • Mineral Filler Low Value Products • Source of Al2O3 • Refractories
Commercial EconomicsPREMIUM GRADE CRITERIA A high priced Kaolin has : • Superior Brightness • Superior Whiteness • Desired particle size • High opacity (good hiding power) • Chemical purity • Low viscosity (for paper markets) • Other properties - abrasivity, conductivity, etc
Pigment markets - Brightness Competitors Pigment Price per tonne (A$) • 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
KOREA JAPAN CHINA TAIWAN CANADA West Coast THAILAND MALAYSIA USA INDONESIA EUROPE AND MIDDLE EAST PROJECT LOCATION AUSTRALIA TASMANIA NEW ZEALAND
KAOLIN FORMATION • Economic deposits mainly weathering related • Associated with laterite and bauxite • Formed in wet/dry tropical climate • Over 1500m rain pa • Leaching process
LATERITIC WEATHERING BAUXITE IRONSTONE MOTTLED PALLID BEDROCK --- Highest water --- Lowest water Leaching of cations
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 • Feldspars & clays kaolinite • 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 • 1986 - Drilled 93 holes - geology only • 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 • Moving goal posts • Rolls Royce plant • Major cost over-runs • No coordination of consultants/contractors
GEOLOGICAL HISTORY….. Cretaceous - Marine Shale
Uplift and Weathering... Claystone Rolling Downs Formation
Tertiary Sheet Fluvials Bulimba Formation
Fluvial Channel Develops Namaleta Creek Floodplain
Further Weathering…... K3 Fluvial Claystone
Wet Plant ML and Drilling DRILLHOLES AND OUTLINE OF FLUVIAL CHANNEL Green – RC holes Black – AKL grade control holes
RESOURCES Purple – inferred claystone Grey – measured claystone Blue – inferred fluvial
Resource Summary Total 100 years at 75,000tpa.
Hydrous Kaolins Plant capacity 75,000 tpa Wide range of industrial applications Represents the bulk of world supply Target of paint & rubber markets Calcined Kaolins Plant capacity 75,000 tpa Higher performance Better brightness, opacity Competes with TiO2 Premium price Limited number of producers Paint, rubber, paper Skardon Product Range
Stage 1 Processing: Wet Plant Kaolin Ore Blunger Degritting Centrifuge Sand Decanter Centrifuge Delaminating Mill, Leaching circuit Disc-nozzle Centrifuge Tailings Dam High Gradient Magnet Separator Membrane Filter Pipeline to Dry Plant
Stage 2 Processing: Dry Plant Pipeline from Wet Plant Spray Dryer Pulveriser Calcining Kiln HYDROUS KAOLIN Pulveriser CALCINED KAOLIN
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 • Exposed just south of Fall Line • Cap bentonite • Cretaceous 60% -2micron • Tertiary 85% -2micron
ADVANTAGES Two types of kaolin Expertise Reputation Transport for E USA & Europe DISADVANTAGES Older updated plants Mine locations High stripping ratios Transport to Asia Georgia - Economics
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.
ADVANTAGES Fine Kaolin Modern plant DISADVANTAGES Pipeline distance Transport to Asia Amazon Economics
Summary of the Skardon River Kaolin Project • Long mine life • Growing international demand • Premium products • Exceedingly low CAPEX entry price • Best logistics for Asia • Marketing and distribution agreements • Technical Management Expertise