This document provides an overview of nickel laterite deposits, including: 1. Laterites form through chemical weathering of ultramafic rocks under tropical conditions, which leaches silica and magnesium and concentrates iron and other elements like nickel. 2. A laterite profile develops distinct zones from top to bottom with varying iron, nickel, magnesium, and other element concentrations based on the degree of weathering. 3. Major nickel resources are found in laterites, which make up 69% of the world's nickel resources compared to 31% in sulphide deposits. The top five countries by contained nickel in laterites are New Caledonia, Indonesia, Australia, Philippines, and Cuba.

1. Red Laterite
Yellow
Laterite
Saprolite
zone
Bedrock pinnacle

2. 1. Overview of Nickel and its deposits
2. What are nickel laterites
3. Description of a laterite profile
4. Chemical weathering of ultramafic rocks
5. Factors that influence laterite formation
6. Role of various elements during laterisation
7. Minerals associated with ultramafics and laterites
8. Physical and chemical properties of nickel laterites
relevant to their exploitation
9. Processing of Nickel Laterites
10. Exploration strategy and Management of Nickel Laterite

4.  Nickel was first discovered in 1751
 Derived from German “kupfernickel”  false copper
 Major uses of nickel:
 Stainless steel 65%
 Specialty alloys 12%
 Plating 8%
 Other uses 15%
 Addition of nickel imparts corrosion resistance, and ability
to withstand high temperatures and pressures
 Primary nickel supply comes from newly mined ores
 Secondary nickel supply comes from recycling scrap

5.  Major Nickel producing companies:
1. Norilsk 243,000 t (19%)
2. CVRD Inco 221,000 t (17%)
3. BHP-Billiton 146,000 t (11%)
4. Falconbridge 114,000 t (9%) [Now Exstrata]
5. Jinchuan 93,000 t (7%)
6. Eramet 59,000 t (5%)
7. Sumitomo 51,000 t (4%)
 Major Nickel producing countries:
1. Russia (Norilsk Nickel group)
2. Canada (CVRD Inco, Falconbridge, Sheritt)
3. Australia (BHP-B, Minara, Cawse, LionOre)

6.  Sulphide nickel deposits
 Nickel as nickel sulphide  pentlandite, millerite
 Nickel ores processed through milling and smelting
 Laterite nickel deposits
 Oxide Ni deposits: Ni as hydroxide in the ferruginous zone
 Clay silicate deposits: Ni as clay silicate
 Hydrous silicate deposits: Ni as hydrous-silicate in
saprolite
 Nickel ores processed through pyro-metallurgy (smelting)
or hydro-metallurgy (leaching)

7. Mt
Ore
%
Ni
Contained
Nickel
Mt
Relative
%
SULPHIDES 10,594 0.58 62 31%
LATERITES 10,382 1.32 140 69%
TOTAL 20,976 0.96 202 100%
Excluding sea-based manganese nodules

8. PRIMARY Ni PRODUCTION WORLD Ni RESOURCES
SULPHIDE
SULPHIDE
LATERITE
LATERITE
60%
40% 30%
70%

9. Cuba Dominican
Republic
Brazil
Columbia
Guatemala
Albania
Greece
Philippines
Indonesia
PNG
New
Caledonia
Australia
Venezuela
Burma
India
Madagascar
Producing Countries
Non Producing Countries
Ivory Coast
Zimbabwe
Ethiopia
Burundi

10. CUBA
INDONESIA
AUSTRALIA
LATERITES SULPHIDES
NEW CALEDONIA
PHILIPPINES

11. Mt Resource %Ni Mt Ni %
Caribbean 2785 1.26 35.0 25
New Caledonia 1890 1.52 28.7 20
Indonesia 1401 1.63 22.8 16
Philippines 1162 1.30 15.1 11
Australia 1144 0.95 10.9 8
Africa 800 1.33 10.7 8
C. & S. America 661 1.60 10.6 8
Other 539 1.08 5.8 4
Total 10382 1.34 140 100

12. Caribbean
25%
New
Caledonia
20%
Indonesia
16%
Philippines
11%
Australia
8%
Africa
8%
C. & S.
America
8%
Other
4%

14.  Buchanan Hamilton introduced the term for the “brick
stones” used by people in South India that hardened on
exposure to the sun (Latin word “later” means brick)
 Current use of the term “laterite” does not require this
hardening characteristic
 Nickel laterites are:
 Residual soils
 Rich in sesquioxides of iron with some nickel enrichment
 Have developed over mafic/ultramafic rocks
 Through processes of chemical weathering and supergene
enrichment
 Under tropical climatic conditions

15.  A soil is a naturally occurring body made up of
layers which differ from the parent material in
their physical, chemical, mineralogical,
biological and textural characteristics.
 Soils are formed through several processes that
include:
 Addition through transportation
 Removal at the top of the profile through erosion
 Removal from the soil profile through leaching
 Migration of elements through the soil profile
(through leaching)

16. TEMPERATURE
HUMIDITY / RAINFALL
TUNDRA
Gray
Desert
and Sierozem
Brown
Chestnut
Degraded
Chernozem
Brunizem
PODZOL
Brown Podzolic
Gray-Brown Podzolic
Red Desert
Redd
ish
Bro
wn
Reddish
Chestnut Reddish
Prairie
Red-Yellow Podzolic
LATERITE
Reddish brown Latosolic
Yellowish brown Latosolic
TUNDRA
PODZOL
Red
Desert
Degraded
Chermozem
Brunizem
Brown Podzolic
Gray-Brown
Podzolic
Reddish
Prairie
Red-Yellow
Podzolic
Yellow-brown
Latsolic
Reddish-brown
Latsolic
LATERITE
Gray
Desert
&
Sierozem
Brown
Chestnut
Chemozem
Reddish
Brown
Reddish
Chestnut
Dry
Dry
Wet
Wet
Cold Cold
Hot Hot
GREAT SOIL GROUPS OF THE WORLD

17.  In stratigraphy, laterites represent
unconformities (break in stratigraphic sequence)
 Laterites make poor soils for agriculture
 Laterites are source of metals:
 Ni, Co, Cr, Fe (from laterites derived from ultramafic
rocks)
 Al (from laterites derived from aluminous rocks)

19. P.T. INCO
Development of weathering crust on
a peridotite boulder (Sorowako)

20. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock pinnacle

21. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
Hematite zone
Limonite zone
Zone of altered bedrock
(clayey matrix + boulders)
Fresh bedrock Ferruginous
Zone
Intermediate zone

22. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
• Fresh bedrock
• Joints and fractures opening up as
hydrostatic pressure is removed
• Percolating rain water circulating along
joint and fracture surfaces
• Signs of incipient weathering
• Original rock composition and texture
fully preserved

24. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
• Rock fragments + saprolised boulders +
precipitated silica + garnierite
• Chemical weathering proceeding actively
along joints and fractures
• Silica and magnesia being leached out
• Rock porosity increasing with time
• Bulk density decreasing with time
• Zone still not collapsed
• Original rock texture still preserved
• Upper part more ferruginous than lower
part
• High SiO2 and MgO contents
• Low Fe content
• Zone of supergene Ni enrichment

27. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
• Soft smectite clays + silica
• Chemical weathering (silica & magnesia
leaching) extremely advanced
• Rock porosity at its maximum
• Bulk density at its lowest
• Zone is ready to collapse
• Moisture content at its highest
• Original rock texture barely discernible
• Upper part more ferruginous than lower
part
• Often the preferred location for Mn and
Co enrichment

28. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
• Zone rich in hydrated Fe oxides +
• Chemical weathering near complete
• Silica and magnesia fully leached out
• Residual concentrations of other
elements at near maximum
• Rock porosity decreasing with time
• Bulk density increasing with time
• Zone is collapsed
• Original rock texture obliterated

29. Red Laterite
Yellow Laterite
Saprolite zone
Bedrock
• Zone rich in hematite and less hydrated
Fe oxides (goethite)
• Chemical weathering complete
• Silica and magnesia fully leached out
• Residual concentrations of other
elements at maximum
• Rock porosity decreasing with time
• Bulk density increasing with time
• Zone is completely collapsed
• Original rock texture obliterated
• Further changes include formation of
duricrust (ferricrete or silcrete)

30. 0
5
10
15
20
DEPTH (m)
WEST BLOCK
UNSERPENTINISED
EAST BLOCK
SERPENTINISED
Limonite
Overburden
Iron cap
Limonite ore
Saprolite Ore
Bedrock

31. 0
20
40
DEPTH (m)
SILICATE
(eg New Caledonia)
CLAY
(eg Murrin Murrin)
OXIDE
(eg Moa Bay)
Cuirasse
Red
limonite
Yellow
limonite
Earthy
ore
Ore with
boulders
Rocky
ore
Bedrock
Bedrock
Saprolite
(Serpentine,
chlorite,
smectite)
Smectite
zone
Ferruginous
zone
Colluvium
Bedrock
Saprolite
Limonite
Limonite
overburden
Iron cap

32. Ferricrete
Limonite
Nontronite
Saprolite
%Ni
.2 -.5
.6-1.4
1.2
.4
%Co
.02
.1-.2
.08
.02
%Mg
.6
1-2
3.5
12.0
%Fe
35+
45
18
9
Ferricrete
Limonite
Nontronite
Saprolite
Altered Peridotite
WA
Laterite
Profile
Dryer Climate
(Western Australia)
Humid Climate
(Indonesia hills)
%Ni
.2 -.5
1.2-1.7
1.5 -3
%Co
.02
.1-.2
.05-.1
%Mg
.6
1-2
10-20
%Fe
35+
45
10-25
%Ni
.2 -.5
1.2-17
1.5-3
%Co
.02
.1-.2
.05-.1
%Mg
.6
1 -4
10-30
%Fe
35+
45
10-20
Humid Climate
(Goro Plateau)

33. BEDROCK
SAPROLITE
Supergene
Nickel
enrichment
Supergene
Cobalt
enrichment

35. TERMINOLOGY
 Rich in mafic (ferro-magnesian) minerals
 Generally contain less than 45% SiO2 (except pyroxenite)
 Colour indices of more than 70
 Generally lack any feldspar
 No exact counterpart among lavas (extrusive rocks)
 The density of ultramafic magma is too high to rise through the sialic
portion of the crust
FORMATION
 Crystal settling (by gravity) in a magma chamber (layered intrusions)
 Intrusion of hot, semi-solid, crystalline mass (dykes, lenses, stocks)
 Through obduction of oceanic crust upon continental landmass in
orogenic belts

36. DUNITE
 Monomineralic rock composed entirely of olivine. Originally seen at Dun
Mountain in New Zealand
PYROXENITE
 Monomineralic rock composed entirely of pyroxene
 Orthopyroxenites: Bronzitites
 Clinopyroxenites: Diopsidites; diallagites
HORNBLENDITES
 Monomineralic rocks composed entirely of hornblende
SERPENTINITE
 Monomineralic rock composed entirely of serpentine
PERIDOTITE
 Ultramafic rocks containing olivine and other mafic minerals
 Pyroxene peridotite / Hornblende peridotite / Mica peridotite

37. OLIVINE
PYROXENE HORNBLENDE
Dunite
Peridotites
Pyroxenites
Hornblendites
Harzburgite
Lherzolite
Wehrlite
Orthopyroxenite
Websterite
Clinopyroxenite
90% OL.
40% OL.
Classification
In terms of
Oliv.-Pyrox.-Hnde

38. OLIVINE
ORTHO-
PYROXENE
CLINO-
PYROXENE
Dunite
Clino-
Pyroxenite
Ortho-
Pyroxenite
Olivine
Websterites
OL+OPX+CP
Websterites
Wehrlite
Harzburgite
Olivine
Orthopyroxenite
Olivine
Clinopyroxenite
40% OL
Classification
In terms of
Olivine-Opx-Cpx
Lherzolite
OL+OPX+CP

40.  Ni in ultramafic rocks is primarily in mafic minerals
 High in olivines (0.2 – 0.3% Ni)
 Low in orthopyroxenes (0.05 – 0.1% Ni)
 Very low in clinopyroxenes (< 0.05% Ni)
 Thus, decrease in the olivine content of the ultramafic
reduces the overall nickel content of the rock:
 Highest Ni grades in dunites
 Lower Ni grades in peridotites
 Lowest Ni grades in pyroxenites
 Ni in mafic minerals is largely as a replacement of Mg
 Ni in mafic minerals falls with the order of crystallisation
 Some Ni may exist as replacement of the larger Fe atoms
 Primary chromite and magnetite may contain minor Ni

41. Four major processes under which rocks change their physical or chemical
properties:
 Melting (at very high temperatures)
 Metamorphism (high temperatures / pressure / addition)
 Hydrothermal alteration (through high-temperature fluids)
 Weathering (at ordinary temperatures and pressure)
Types of weathering:
 Physical (mechanical breakdown of rocks)
▪ erosion, thermal expansion/contraction, action of plants
 Chemical (breakdown of rocks through chemical processes)
▪ contact with water, oxygen, carbon dioxide, etc.

42. Unserpentinised
Ultramafic
Rocks
Serpentinised
UM Rocks
Chemical
weathering
under
tropical
conditions
Nickel
Laterites

43. “The process in which rocks react to atmospheric, hydrospheric and biologic agencies to
produce mineral phases that are more stable”
1. Hydrolysis
Oxygen, carbon dioxide, ground water, dissolved acids attack the minerals in
the rock
2. Oxidation
Elements released by chemical weathering are oxidised
3. Hydration
Reaction with water adds the hydroxyl ion to newly formed minerals
4. Solution
The more soluble products of weathering are dissolved and removed
And the cycle continues .....

44. RAIN AND THUNDER STORMS
Nitrous oxides, CO2
HUMOUS (Organic) LAYER
WATER TABLE
ZONE OF OXIDATION
(Reducing conditions)
(Reducing conditions)
Acidic
Rain
Acidic
Rain

45.  The sum of negative and positive charges are equal
within a crystal (Pauling’s Rule)
 However, exposed atoms and ions on crystal surfaces
possess unsaturated valencies and are thus charged
 Water molecules are attracted to the charged surfaces
 Attractive forces cause polarisation of water into H+
and OH- ions
 Hydroxyl (OH)- ions then bond to exposed cations
 Hydrogen ions (H)+ bond to exposed oxygen and other
negative ions
 In the case of silicates, H+ attacks the Si-O-Si bonds
and releases silica as orthosilicic acid (H4SiO4)

46.  Common oxidising agent in the soil is oxygen dissolved in ground water
 Much of ferrous ions in the weathering profile are converted to ferric
state under highly oxidising conditions.
 Oxidising conditions exist only above the water table
 Below the water table, conditions are generally reducing
 Organic matter at the very top may also create reducing conditions
 Hot, well-drained environment favours oxidation through the
destruction of organic matter and lowering of water table
 Cool, poorly-drained environment promotes accumulation of organic
matter and reducing conditions

47.  In the presence of Hydroxyl ion (OH)-, freshly created oxides are converted to
hydroxides
 The more common hydroxides found in lateritic soils include:
 Hydrated iron oxides: Goethite / Limonite
 Hydrated Aluminum oxides:Boehmite / Bauxite / Gibbsite
 Hydrated manganese oxides: Pyrochroite / Manganite /
Psilomelane
 Many new secondary mafic minerals are formed due to hydration:
 Serpentine /Talc / Chlorite
 Hydration also results in the formation of clay minerals:
 Kaolinite; Halloysite; Illite; Smectites; Saponite

48.  For chemical weathering to continue, broken down constituents
must be removed
 Solution of broken down constituents exposes new surfaces
 Dissolved constituents are removed by percolating ground waters
 Ground waters generally travel from top to bottom in a
weathering profile
 Dissolved constituents are eventually drained out to rivers, lakes
and the ocean
 The relative proportions of dissolved constituents in ground water
confirm the relative solubilities of various oxides in the laboratory
 Dissolved CO2 in ground water is a very strong leaching agent

49.  Solubilities of some minerals:
 Halite (NaCl): 3005 g/litre
 Gypsum (CaSO4.2H2O): 1.8 g/litre
 Silica gel: 0.12 g/litre
 Quartz (SiO2): 0.007 g/litre
 Relative solubilities of some minerals (Paul Golightly):
 Forsterite
 Enstatite
 Serpentine
 Talc
 Amorphous silica
 NickelTalc (Kerolite)
 Gibbsite
 Goethite
Highly soluble
Highly insoluble

50.  Polynov’s estimate of elemental mobilities:
 Hudson’s estimate of elemental mobilities
Cl > SO4 > Na > Ca > Mg > K > Si > Fe+++ > Al
 Berger’s estimate of hydroxide mobilities:
Cl SO4 Ca++ Na+ Mg++ K+ SiO2 Fe2O3 Al2O3
100 57.0 3.0 2.4 1.3 1.25 0.2 0.04 0.02
Soluble Supergene Residual
Mg Mn++ Co++ Ni++ Al+++ Cr+++ Fe+++
3.1 1.3 -1.7 -3.2 -15.3 -16.4 -18.1

51.  Highly soluble and highly mobile
 Easily leached out of the laterite profile
 Taken to lakes, rivers and the sea
Ca, Na, Mg, K, Si
 Limited solubility –— Supergene enrichment
 Partly soluble in acidic ground water
 Insoluble in the presence of more soluble elements (Si,
Mg)
Ni++, Co++, Mn++
 Non soluble and residual
 Insoluble in ground waters at ordinary pH / Eh conditions
 Make up bulk of the residual soil
Al+++, Fe+++, Cr+++,Ti, Mn+++

52. Forsterite: 2MgO.SiO2 (MgO = 57.3%)
 Highly unstable in weathering
environment
 Individual SiO4 tetrahedra are
weakly bonded by cations
 Magnesia is highly soluble in ground water
 Release of magnesia breaks down the Olivine structure
 Breakdown of Olivines releases various cations:
 Mg, Fe, Al, Ni, Mn
Sorowako Olivine:
• FeO = 9.0%
• Al2O3 = 0.4%
• NiO = 0.37%
• MnO = 0.12%
• Cr2O3 = 0.02%
• TiO2 = 0.02%
Replacements

53. Enstatite: MgO.SiO2 (MgO = 40.2%)
 Relatively unstable in weathering
environment (but < Olivine)
 Individual SiO4 tetrahedra are
bonded by shared Oxygen
 Magnesia is highly soluble in
ground water
 Release of magnesia breaks down the Pyroxene
 Breakdown of Pyroxenes releases various cations:
 Mg, Fe, Al, Ca, Cr, Mn, Ni
Sorowako Pyroxene:
Opx Cpx
• FeO = 6.0 2.5
• Al2O3 = 3.2 3.5
• CaO = 1.9 21.7
• NiO = 0.08 0.05
• MnO = 0.13 0.08
• Cr2O3 = 0.58 0.86
• TiO2 = 0.05 0.09
Replacements

54.  Serpentine: 3MgO.2SiO2.2H2O [H4Mg3Si2O9]
 Magnesia is leached out first, leaving behind a silica
enriched phase or montmorillonite and chlorite
 Ni can replace the magnesium being leached.This results
in the formation of:
 Nickeliferous serpentine
 Through a similar process, nickel is also fixed inTalc,
Chlorite, and Smectite
 Eventually, montmorillonite and chlorite also break down,
releasing remaining magnesia and silica and forming iron
sesquioxides

55. Course of Laterisation
MgO
SiO2
FeO or F2O3
Bedrock
Soft
Saprolite
Hard
Saprolite
All compositions are shown
in terms of the three oxides
PATH OF
LATERISATION
Limonite

56. Highly Mobile
Ca, Na, K, Mg
Less Mobile
Si
Non-Mobile
Fe, Al, Cr, Ti
Olivine
Opx
Cpx
Montmorillonite
Illite
Nontronite
Goethite
Siliceous
Nontronite
Ultramafic
Rocks

57. Course of Laterisation
MOBILE vs. NON-MOBILE ELEMENTS
IN COMMON MINERALS ASSOCIATED WITH LATERITES
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
NON-MOBILE ELEMENTS (Al2O3 + Fe2O3)
MOBILE
ELEMENTS
(Na2O+K2O+CaO+MgO+SiO2)
Halloysite
Kaolin
Illite
NATURAL OLIVINES
& PYROXENES
Serpentine
CLAYS &
CHLORITE
HYDROXIDES OF Al AND Fe
Clinochlore
Montmorillonite
Hematite
Parent rock
Saprolite with clays
having low Fe & Al
Saprolite & intermediate
zone with clays having high
Fe & Al
Hydroxides of aluminium and
iron (yellow & ochre colour)
Red
laterite
Nontronite

58. Dunite Goethite
Mineral Olivine Goethite
Composition (Mg,Fe)2SiO4 Fe2O3.H2O
Block size, m. 1 x 1 x 1 1 x 1 x 0.32
Particle density 3.2 4.4
Dry Bulk Density 3.2 1.1
Fe content, % 5.5% 50%
Kg of Fe 176 176
Dunite
Goethite
Volume of Goethite =
Dunite: density x % Fe
Goethite: density x % Fe
= =
17.6
55.0
0.32
1.0 m
0.32 m

59. CaO = 0.5%
Na2O = 0.1
K2O = 0.1
MgO = 45%
SiO2 = 41%
MnO = 0.1%
CoO = 0.005%
NiO = 0.4%
Al2O3 = 1.1%
Cr2O3 = 0.5%
Fe2O3 = 10%
Highly mobile;
quickly leached.
(87%)
Less mobile;
supergene
enrichment.
Non-mobile;
residual
concentration.
Acidic
Rain
1m
3m
Ultramafics
(< 1%)
(12%) Limonite

61. WEATHERING
SYSTEM
Temperature
Rainfall
Acidity of rain
Seasonality
ATMOSPHERIC BIOSPHERIC
HYDROSPHERIC LITHOSPHERIC
COMBINATION
Vegetation type
Decay intensity
Microbial activity
Human activity
Water availability
Water absorption
Up/down movement
Porosity/drainage
Water table position
Water table fluctuation
Geomorphology
Rock composition
Mineral grain size
Mineral stabilities
Porosity
Fractures & joints
pH (acidity)
Eh (Redox)
Rate of removal
Time duration
FACTORS THAT INFLUENCE CHEMICAL
WEATHERING

62.  TEMPERATURE
 Each 10 C change increases weathering speed by 2-3 times
 Chemical weathering in tropics is 20-40 times higher than in
temperate regions
 RAINFALL
 Acidity of rain (dissolved CO2, Nitrous oxides)
 Amount of precipitation (higher rainfall = higher leaching)
 Seasonality:Constant humid vs.Wet/dry seasonal
 EFFECT OF CLIMATE
 Hematitic soils develop in hot and dryer climate
 Goethitic/limonitic soils develop in hot and wet climate
 Hot and humid climate leads to complete leaching of SiO2 & MgO
 Seasonal wet/dry climate leads to formation of smectites
 Climate can vary considerably over time [fossil laterites]

63. Rainfall,
0
–
3,000
mm
Temperature,
0
-
30ºC
Tundra
Taiga
(Northern
Forests
Steppes
Semi-desert
&
Desert
Savannas
Savannas
Tropical
Fe/Al
K
I/M
K
I/M
Bedrock with incipient
chemical alteration
Legend:
Fe/Al: Oxides/Hydroxides
K: Kaolinite clays
I/M: Illite/Montmorillonite
SOILS & RELATIVE DEPTH OF WEATHERING

64.  Tropical climate leads to rapid decay of biological
matter
 Microbial activity hastens the decay process
 Vegetation decay forms various organic acids: humic,
carbonic, fulvic, crenic, apocrenic, oxalic and lichenic
acids
 Presence of organic matter creates reducing
conditions (assists the conversion of ferric to ferrous
iron)

65.  WATER ABSORPTION
 WATERTABLE
 Vadose zone: lying above the water table.
This zone is wetted by meteoric water that comes from
above. Zone of non-saturation. Zone of oxidation.
 Phreatic zone: lying below the water table.
This zone is wetted by water held in pore spaces.
Zone of saturation. Zone of reduction.
 FLUCTUATION OFWATERTABLE
 Assists greatly in flushing the laterite of dissolved material
 Controls supergene enrichment of Mn and Co

66.  The position of water table depends on:
 Amount of rainfall
 Ground porosity/permeability
 Topographic characteristics
 Permanently High water table
 Much of rock filled with water
 Less oxygen being supplied
 Permanently Low water table
 Likely less rainfall and little ground water to attack minerals
 Slow removal of dissolved material
 Fluctuating water table
 Varying zones of oxidation and reduction
 Frequent flushing of system to remove dissolved material

67.  PARENT ROCK COMPOSITION
 Rocks high in Fe yield iron laterites (mafic / ultramafic)
 Rocks high in Al yield aluminous bauxites (syenites / trachytes)
 Rocks with some nickel content yield nickeliferous laterites
 Unserpentinised peridotites are more susceptible to weathering than
serpentinised peridotites
 MINERAL GRAIN SIZE
 Coarse-grained rocks are more susceptible to weathering
 FRACTURES / FAULTS / JOINTS
 Provide access to acidic ground waters; assist in removal of dissolved
material
 STABILITYOF MINERALS
 Process of chemical weathering leads to the formation of secondary
minerals that are increasingly more stable

68. Olivine Ortho-pyroxene Clino-pyroxene
SiO2 40 55 – 62 50 – 53
TiO2 0.02 – 0.05 0.02 – 0.05 0.1 – 0.6
Al2O3 0.4 – 0.6 1.7 – 3.2 3 – 4
Cr2O3 0.02 – 0.2 0.6 0.8 – 0.9
Fe2O3 All iron reported as FeO
FeO 8 – 10 5 – 6 2.5 – 4.0
MnO 0.12 – 0.16 0.1 0.1
NiO 0.3 – 0.5 0.06 – 0.1 0.05 – 0.07
CoO 0.01 – 0.02 0.006 0.003
MgO 47 – 51 32 – 35 18 – 22
CaO 0.04 – 0.07 1 – 2 17 – 22

69. Olivine
Augite
Hornblende
Biotites
Ca-Plagioclase
Na-Plagioclase
K-Feldspar
Muscovite
Quartz
Goldich (1938) determined the following sequence of decreasing
weathering susceptibilities for the common rock-forming minerals

70.  In general, crystal structure of mafic silicates controls weathering:
 Olivine, with its independent silicon tetrahedra is the most unstable
 Pyroxenes, with polymerised chains, are more stable
 Amphiboles, with their ring structures, are still more stable
 Clays and micas with sheet-like structure are the most stable
 Reiche (1943) devised aWeathering Potential Index:
Mineral WPI Mineral WPI
Forsterite 66 Biotite 22
Enstatite 55 Orthoclase 12
Anthophyllite 40 Quartz 0
Augite 39 Muscovite -10.7
Hornblende 36 Kaolinite -67
Talc 29 Gibbsite -300

71. Ultimate
stable
residuum
Hematite [Fe2O3]
Goethite [Fe2O3.H2O]
Limonite [Fe2O3.3H2O]
Boehmite [Al2O3.H2O]
Bauxite [Al2O3.2H2O]
Gibbsite [Al2O3.3H2O]
Secondary
minerals
Kaolinite
Smectites
Kaolinite
Primary
minerals
Olivine
Pyroxene
Plagioclase
Alkali Feldspars
Increased
Leaching

72.  The progression of clay minerals generally follows
the line of reduction of leachable components (SiO2,
MgO):
Type of clay % Leachables % Non-leachables
Nontronite 38.0 (SiO2) 50.6 (Fe2O3)
Halloysite 40.8 (SiO2) 34.6 (Al2O3)
Kaolinite 46.5 (SiO2) 39.5 (Al2O3)
Siliceous
nontronite
57.5 (SiO2) 38.2 (Fe2O3)
Montmorillonite 62.3 (CaO, MgO, SiO2) 18.3 (Al2O3)
Clinochlore 68.7 (MgO, SiO2) 18.3 (Al2O3)

73.  Control of water absorption
 High water run-off on steep slopes
 High water absorption on moderate & gentle slopes
 Water logging and saturation in basin areas
 Rate of sub-surface drainage and removal of dissolved
 Rate of erosion
 Control of laterite preservation
 Slopes of <15% are generally required to preserve the laterite
 Ideal landforms for laterite development & preservation
 Rolling to gently sloping morphology
 Elevated area
 Surface runoff is not excessive
 Sub-surface drainage is good

74. Steep Hill
Depression / basin
Gentle Hill
Plateau
River Terrace
Dissected Plateau

75.  pH of normal waters lies between 4 and 9
 Most oxides show some solubilities in natural waters
 Oxides of Ca, Mg, Na and K are completely soluble
 Oxides ofTi,Al, and Ferric iron (Fe+++) are insoluble
 Solubilities of many oxides are pH dependent:
 Ti, Ca, Fe++ iron
 Alumina is not soluble in the normal ground water pH
 Alumina is soluble at pH < 4 and at pH > 10
 With abundant organic matter available, pH may drop to < 4
 Plant roots carry low pH values, commonly 4 but down to 2
 Where abundant basic minerals are being weathered (olivine, pyroxene,
nepheline), pH conditions may climb to beyond 9

76.  Redox Potential of a system is a measure of the ability to bring about reduction
or oxidation reactions
 Reduction: decrease in the positive valency of an element (Fe+++ to Fe++) or an
increase in the negative valency of an element
 Oxidation: increase in the positive valency of an element (Fe++ to Fe+++) or the
decrease in the negative valency of an element
 The neutral value of Redox Potential is zero
 At lower values (-), the R. Potential represents reducing conditions
 At higher values (+), the R. Potential represents oxidising conditions
 Two factors control the Redox Potential during weathering:
 Atmospheric oxygen (creates oxidising conditions)
 Organic matter (creates reducing conditions)

77. 2 4 6 8
0 10 12 14
1.0
- 0.6
- 0.4
- 0.2
0.0
0.2
0.4
0.6
0.8
Fe++
Fe+++
Fe++
Fe+++
O2
H2
H2O
H2O
Natural
Environments
Eh
pH
Reducing
Oxidising
Acidic Alkaline

78.  Laterisation rate based on mineral solubilities:
 1mm/100 years; 1m/100,000 years; 10m/million years
 Laterisation rate based on drainage water compositions
(P. Golightly, 1979)
 1.4mm/100 years; 1.4m/100,000 years; 14m/million years
 Chemical weathering in New Caledonia (Trescases, 1975)
 2.9-4.7mm/100 years
 Chemical weathering in Africa (Tardy, 1969)
 0.5-3.3mm/100 years
 Chemical weathering tends to slow down with time
 Interruptions in chemical weathering
 Fossil laterites

79. Water table
Water table
Regolith
Weathering Front
Thick Regolith due to
soil preservation
Thick Regolith due to
deposition of transported soil
Thin Regolith due to
soil erosion

81.  Ca
 Na
 Mg High mobility; mostly leached out
 K
 Si
 Mn
 Co Medium mobility; supergene
enrichment
 Ni
 Al
 Cr No mobility; residual enrichment
 Fe

82.  Ca is present essentially in clinopyroxenes
 Ca in olivines = maximum 1%
 Ca in Orthopyroxenes = maximum 2%
 Ca in clinopyroxenes = 22% at Sorowako; 18% at Goro
 Ca is extremely soluble in ground water
 Practically all Ca is leached out in the early
stages of laterisation
 Final laterite residuum (goethite/limonite) have
Ca generally < 0.05%

83.  Na and K present in ultramafic rocks in
extremely small quantities (< 0.1% each)
 Na and K are highly soluble in ground waters
and are quickly leached out of original
ferromagnesian minerals
 All Na goes to the rivers/lakes/sea
 K is preferentially fixed in clay minerals
(vermiculite, montmorillonite, chlorites,
micas, illites)
 Relative abundance of Na and K:
Wt.% in
earth’s crust
Wt.% in
Igneous rocks
Wt.% in
sea water
Na 2.8 2.29 1.08
K 2.6 2.22 0.04

84.  Magnesia is present in Olivine, Pyroxene and Serpentine
 Olivine = 57%; Enstatite = 40%; Serpentine = 44%
 Magnesia is released by the breakdown of ferromagnesian
minerals
 Magnesia is highly soluble in ground water
 It is the first major component to be leached out in large
quantities
 Some magnesia may stay in the laterite profile to form
clay minerals and nickel hydrosilicates
 Final products of lateritic weathering (hematite/goethite/
limonite) do not contain any magnesia

85.  Silica is present in Olivine, Pyroxene and Serpentine
 Olivine = 43%; Enstatite = 60%; Serpentine = 43%
 Silica is released by the breakdown of ferro-
magnesian silicates
 In humid environments, laterite is constantly flushed
and little silica gets fixed as smectite/nontronite clays
 In wet-dry environments, flushing of laterite profile is
poor and silica gets fixed as smectite/nontronite clays
in the Intermediate Zone
 In the alkaline environment (where MgO is being
released), silica can precipitate from solution as
amorphous silica (silica veins, boxwork, coatings)

86. 0
5
10
15
20
25
30
35
40
45
5 10 15 20 25 30 35 40 45 50 55
% Fe
%
SiO2,
%
MgO
SiO2
MgO

87.  Iron in ultramafics: Ferrous Ferric
 In olivine (MgO.FeO.SiO2) : Fe++
 In pyroxene (MgO.FeO.2SiO2) : Fe++
 In chromite (FeO.Cr2O3) : Fe++
 In ilmenite (FeO.TiO2) : Fe++
 In magnetite (FeO.Fe2O3) : Fe++ Fe+++
 Fe in mafic minerals causes great instability during weathering
 Breakdown of mafic minerals releases Ferrous ions
 Ferrous ions are quite soluble and mobile
 Ferrous ions get quickly oxidised to ferric ions, as:
 Hematite / Maghemite,Goethite, Limonite
 Iron in primary magnetite and ilmenite oxidises to form:
 Hematite / Maghemite,Goethite, Limonite

88.  Favourable conditions for the formation of
hematite and goethite (Kampf and
Schwertmann, 1983):
Temperature Excess
Moisture
Soil
Carbon
pH Altitude
Hematite High Low Low High Low
Goethite Low
< 15 C
High
> 1000mm
High
> 3%
Low High

89.  Alumina is present in:
 Pyroxenes (as impurity and as solid solution)  2-4%
 Common Spinel (MgO.Al2O3)
 On the breakdown of pyroxenes, alumina is temporarily
fixed in the chlorites (Clinochlore: 5MgO.Al2O3.3SiO2.4H2O)
 After the breakdown of chlorites, alumina is fixed in
gibbsite (Al2O3.3H2O)
 Alumina is very insoluble in ground water in the pH range
commonly found (4 – 9)
 Al+++ and Fe+++ are truly residual elements in laterites

90.  Chromite occurs in ultramafics as
 Accessory chromite: FeO.Cr2O3
 Ionic replacement of Mg and Fe in Olivines and pyroxenes
 Trivalent Cr3+ in chromite is insoluble and very stable
 Divalent Cr2+ in ferromagnesian minerals is soluble and mobile
 Some Cr2+ is oxidised to Cr3+ and thus stabilised
 Some Cr2+ is oxidised to Cr6+ as hexavalent oxide (CrO3) or hexavalent
chromate (CrO4)2-
 Some hexavalent chrome may naturally get reduced to trivalent
chrome
 Remaining hexavalent chrome may be released to the natural
environment where it is extremely toxic (carcinogenic)

91.  Nickel is present in ferromagnesian minerals as ionic
replacement of Mg and Fe
 Olivines: 0.3%
 Orthopyroxenes: 0.1%
 Clinopyroxenes: 0.05%
 Serpentines: inherited from the primary mafic mineral
 After breakdown of mafic minerals, Ni is released
 Ni is soluble in percolating acidic waters
 Ni is insoluble in alkaline waters in the saprolite zone
 Ni is precipitated as hydrous nickel silicate with
serpentine, chlorite or clay structure
 Some nickel is adsorbed or enters the goethite structure

92.  Minor amounts of Mn and Co are present in the mafic
minerals (Olivine and Pyroxene)
 On the breakdown of mafic minerals, Mn and Co are
released
 Mn and Co are slightly soluble in acidic waters at the top of
the laterite profile
 Mn and Co are very insoluble in alkaline waters
 Mn and Co concentrate at the bottom of the Limonite
Zone
 Much of Cobalt is tied to the manganese wad

93. 0
5
10
15
20
25
30
35
40
45
50
-6 -4 -2 0 2 4 6 8 10 12 14
DEPTH IN METRES
PERCENTAGES
Transition
zone
Fe
SiO2
AlO2O3
MgO
LIMONITE SAPROLITE

94. 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-6 -4 -2 0 2 4 6 8 10 12 14
DEPTH IN METRES
PERCENTAGES
Transition
zone
Cr2O3
MnO
Co
Ni
Supergene Ni
enrichment
LIMONITE SAPROLITE

95. Original
Bedrock
Limonite
Zone
Concentration
Factor
Ni 0.28 1.00 3.6
Fe 6.0 50.0 8.3
Co < 0.007 0.131 18.7
SiO2 40.9 2.3 Leached out
MgO 35.3 1.5 Leached out
Al2O3 1.13 8.5 7.5
Cr2O3 0.45 3.44 7.6
MnO 0.13 1.25 9.6
TiO2 0.01 0.086 8.6

97. +1 +2 +3 Spinels +4 +5 +6
Al2O3
CaO
CoO Co2O3
Cr2O3 CrO3
(CrO4)
FeO Fe2O3 Fe3O4
K2O
MgO
MnO Mn2O3 Mn3O4 MnO2
Na2O
NiO
P2O5
SiO2
TiO

98. Primary
igneous
minerals
Olivine
Pyroxene
Magnetite
Chromite
Mafics Spinels
Hydro-
thermal
minerals
Serpentine
Talc
Chlorite
Secondary
Laterite
weathering
minerals
Oxides &
Hydroxides
Silica
Hematite
Goethite
Limonite
Bauxite
Gibbsite
Serpentine
Talc
Chlorite
Nickel
Silicates
Nepouite
Willemsite
Pimellite
Connarite
Falcondite
Nimite
Noumeite
Magnetite
Clays
Kaolinite
Smectite:
(Mont-
morillonite)
(Nontronite)
Illite
Mixed Layer

99. Brucite
H2O
MgO
FeO
SiO2
Fe2O3
H2O
Fo
Fa
En
Fs
Serp.
Talc
Magnesioferrite
Hematite
Magnetite
Goethite
Limonite
Xanthosiderite
Esmeraldaite
OLIV
PYX
Chlor.
Al2O3
Boehmite
Bauxite
Gibbsite

100. MgO
SiO2
FeO
Forsterite
Quartz
Enstatite
Fayalite
Ferrosilite
Olivines
Pyroxenes

101. Sorowako
Unserp.
Poro
Harzburg.
Tiebaghi
Harzburg.
Goro
Olvine
Goro
Olivine
SiO2 40.3 40.8 39.2 39.9 40.9
TiO2 0.02 0.016 0.046
Al2O3 0.41 0.38 0.63
Cr2O3 0.02 0.21 0.08
Fe2O3 All iron reported as FeO
FeO 8.92 7.8 9.0 7.95 10.27
MnO 0.13 0.12 0.157
NiO 0.37 0.5 0.3 0.356 0.304
CoO 0.013 0.010 0.019
MgO 50.8 49.2 51.4 51.4 47.1
CaO 0.07 0.039 0.69
Totals 101.28 98.3 99.9 100.84 100.2

102.  Forsterite crystallises first (higher melting temperature)
 If the olivine is allowed to react with the liquid magma, it
will change its composition towards ferrous olivine
 As the larger ferrous cations replace the smaller Mg
cations, the melting temperature is progressively reduced
 If the original magma has more silica than can be used by
the olivines (> 40%), then the more siliceous mafic
minerals such as pyroxenes will be formed
 Olivines can take up to 0.5% of NiO (0.4% Ni)
 Ni occurs as replacement of Mg atoms by Ni atoms

103.  General Formula: R2Si2O6 or RO.SiO2
 Orthopyroxenes:
 Enstatite: MgSiO3
 Ferrosilite: FeSiO3
 Hypersthene: (Mg,Fe)SiO3
 Clinopyroxenes:
 Diopside: (Ca,Mg)SiO3
 Augite: (Ca, Mg, Fe)SiO3
Wo (Ca)
En
(Mg)
Fs
(Fe)
Orthopyroxenes
Pigeonite
Augite
Diopside
Ferro-
augite

104. Soroako
Unserp
Opx
Goro
Opx
Poro
Harzburg.
Opx
Tiebaghi
Harzburg.
Opx
Soroako
Unserp.
Cpx
Goro
Cpx
SiO2 55.1 55.9 60.1 61.8 53.2 50.5
TiO2 0.05 0.022 0.09 0.55
Al2O3 3.23 1.72 3.47 4.09
Cr2O3 0.58 0.57 0.86 0.916
FeO 5.79 5.3 5.8 5.4 2.52 3.96
MnO 0.13 0.13 0.08 0.105
NiO 0.076 0.073 0.1 0.06 0.05 0.074
CoO 0.006 0.006 <0.006 0.003
MgO 33.5 35.1 34.7 32.7 18.5 22.3
CaO 1.86 1.04 21.7 17.65
Totals 100.7 99.97 100.7 99.96 101.1 101.5

105. MgO SiO2
H2O
Fo En
Talc
Serpentine
Alteration of Forsterite
+800°C: Fo to En
625-800°C: Fo to En to Talc
500-625°C: Fo to Talc
200-500°C: Fo to Serpentine
Hydro
thermal
Magmatic

106. 0
50
100
150
200
250
300
350
0 2 4 6 8 10 12 14 16 18 20
DEPTH, kilometres
Temperature,
Celcius
Volcanic
Areas
Average
Earth
Thick
Continent
Heat Gradients:
Volcanic Areas: 1 ºC / 10m
Average Earth: 1 ºC / 30-35m
Thick Continental crust: 1 ºC / 100m

107.  Olivine Serpentine
Mg2SiO4 H4Mg3Si2O9
2(MgO).SiO2 3(MgO).2SiO2.2H2O
D = 3.2 D = 2.2 – 2.4
In terms of equivalent MgO content:
6(MgO).3SiO2 6(MgO).4SiO2.4H2O
 Process of serpentinisation involves:
 Addition of water
 Addition of silica (or removal of MgO)
 Release of FeO and its oxidation to Fe3O4 (magnetite)
 Lowering of bulk density (increase in volume)

108.  Lizardite: (not the same as serpentinite)
 Most common form
 Massive
 Antigorite:
 Micaceous, foliated, lamellar, columnar form
 Lamellae are stiff and brittle
 Chrysotile:
 Delicately fibrous
 Fibres are flexible and easily separable
 Occurs in veins or matted masses
 Most common constituent of commercial “asbestos”
 Hazardous to human health if fibres are inhaled

109.  Talc
 H2Mg3Si4O12 (4.8% LOI)
 Sepiolite
 H4Mg2Si3O10 (12.1% LOI)
 High-water Sepiolite
 H10Mg4Si6O21 (14.7% LOI)
 Saponite
 H32Mg9Al2Si10O48 (21.3% LOI)
 Iddingsite
 H8MgFe2Si3O14 (15.9% LOI)

110. Chlorite (clinochlore) falls in composition in
between serpentine and amesite:
 Serpentine H4Mg3Si2O9 (13.0%
LOI)
 Clinochlore H8Mg5Al2Si3O18 (13.0% LOI)
 Amesite H4Mg2Al2SiO9 (12.9% LOI)

111. MgO.FeO
SiO2
Al2O3
Prochlorite
Serpentine
Penninite
Amesite
Chlinochlore
Penninite, Chlinochlore and
Amesite have 13% water of
hydration that is not shown
in the ternary plot
Chlorite compositions

112. SPINELS: RO.R2O3 [R=Fe, Mg, Mn, Ni, Zn]
[R2=Al, Fe, Cr, Mn]
 Magnetite: Fe3O4 (FeO.Fe2O3) [Fe=72.3%]
 Chromite: FeCr2O4 (FeO.Cr2O3)
 Common spinel: MgAl2O4 (MgO.Al2O3)
OXIDES:
 Hematite: Fe2O3
[Fe=69.9%]
 Maghemite: Fe2.66 O4 [Fe=69.9%]
 Silica: SiO2

113. SPINELS
MgO
R2O3
FeO
(MgO.Fe2O3) Magnesioferrite
(MgO.Al2O3) Spinel
Chromite (FeO.Cr2O3)
Magnetite (FeO.Fe2O3)
Hercynite (FeO.Al2O3)

114. FeO
MgO
Fe2O3 Cr2O3
Chromite
Magnesiochromite
Magnesioferrite
Magnetite

115.  Hematite – Fe2O3
 Non-magnetic
 Formed through reduction of Ferric Hydroxides
 Gives the laterite its distinctive “red” colour (laterite rouge)
 Maghemite –Fe2O3 — Fe3O4
 Magnetic variety of hematite
 Partial reduction of hematite through forest fires?
 Crystal structure closer to that of magnetite (Fe2.66 O4)
 Iron deficiency in structure amounts to 11.33%
 The spinel structure of maghemite inverts to the hematite structure
on heating

116.  Hydroxides of Iron: H2O+
 Turgite Fe2O3.0.5H2O 5.3%
 Goethite Fe2O3.H2O 10.1%
 Hydrogoethite Fe2O3.1.33H2O 13.1%
 Limonite Fe2O3.1.5H2O 14.5%
 Xanthosiderite Fe2O3.2H2O 18.4%
 Esmeraldaite Fe2O3.4H2O 31.1%
 Hydroxides of Aluminium:
 Boehmite Al2O3.H2O 15.1%
 Bauxite Al2O3.2H2O 26.1%
 Gibbsite Al2O3.3H2O 34.7%
 Hydroxide of Magnesium
 Brucite MgO.H2O 30.9

117. Brucite
H2O
MgO
FeO
SiO2
Fe2O3
H2O
Fo
Fa
En
Fs
Serp.
Talc
Magnesioferrite
Hematite
Magnetite
Goethite
Limonite
Xanthosiderite
Esmeraldaite
OLIV
PYX
Chlor.
Al2O3
Boehmite
Bauxite
Gibbsite

118. Al2O3
H2O
Fe2O3
Hematite
Boehmite
Goethite
Limonite
Xanthosiderite (Lim)
Esmeraldaite (Lim)
Aluminum Sesquioxide Iron Sesquioxide
Bauxite
Gibbsite
1 H2O
2 H2O
Gibbsite : Al2O3.3H2O
Bauxite: Al2O3.2H2O
Boehmite: Al2O3.H2O
Corundum: Al2O3
Esmeraldaite: Fe2O3.4H2O
Xanthosiderite: Fe2O3.2H2O
Limonite: Fe2O3.1.5 H2O
Goethite: Fe2O3.H2O
Hematite: Fe2O3
Corundum
Group name
“Limonites”

119. 3 – 6m 6 – 9m 9 – 12m
SiO2 1.61 1.33 2.71
TiO2 0.08 0.18 0.09
Al2O3 10.24 11.13 11.95
Cr2O3 3.25 3.37 3.15
Fe2O3 71.96 70.23 68.79
MnO2 0.08 0.04 0.08
NiO 0.41 0.36 0.13
CoO
MgO 0.48 0.46 0.47
CaO 0.02 0.01 0.01
LOI ? ? ?
Totals 88.26 87.13 87.41

120.  Asbolane or manganese wad is black and amorphous
 It occurs as thin coatings on joints, fractures and occasionally as
nodules and beads
 The material is rich in manganese and contains appreciable
quantities of Fe2O3, Al2O3, CoO and NiO
 Significant amount of water of hydration may be present (12% in
a sample from New Caledonia)
Soroako
Lim. 3-6m
Soroako
Lim. 6-9m
Soroako
Lim. 9-12m
Soroako
Saprolite
New
Caledonia
Al2O3 9.0 15.0 7.0 3.5 19.2
Fe2O3 18.4 14.3 36.0 14.2 16.0
Mn2O3 31.0 33.6 33.0 32.0 39.3
NiO 1.7 3.4 2.3 16.2 n.a.
CoO 7.1 7.4 5.0 3.2 7.0

121.  Kaolinite Al2Si2O5(OH)4
 Smectite - Montmorillonite (Al,Mg)2Si4O10(OH)2.nH2O
 Smectite - Nontronite Fe2(Si,Al)4O10(OH)2.nH2O
 Smectite – Saponite (Mg,Fe)3(Si,Al)4O10(OH)2.nH2O
 Illite KAl3Si3O10(OH)2

122. SiO2
MgO NiO
Kerolite - Talc
Serpentine Pimelite
Nepouite
7°A basal
spacing
GARNIERITES
Mg3Si4O10(OH)2.nH2O
Mg3Si2O5(OH)4
Ni3Si4O10(OH)2.H2O
Ni3Si2O5(OH)4
10°A basal
spacing

123. (Serpentine & Talc Division)
Serpentine
(Chrys. / Lizard.)
H4Mg3Si2O9 Pecroaite /
Nepouite
H4Ni3Si2O9
Talc H2Mg3Si4O12 Willemseite H2Ni3Si4O12
Kerolite
(Hydrous Talc)
H2Mg3Si4O12.nH2O Pimellite H2Ni3Si4O12.nH2O
Sepiolite (Dana) H4Mg2Si3O10 Connarite H4Ni2Si3O10
Sepiolite (hi-H2O) H10Mg4Si6O21 Falcondite H10Ni4Si6O21
(Chlorite Division)
Clinochlore H8Mg5Al2Si3O18 Nimite H8Ni5Al2Si3O18
Magnesian Hydrosilicates Nickel Hydrosilicates

124. GARNIERITE COMPOSITION FIELDS
NiO
H2O
SiO2 + Others
Nepouite
Nimite
Falcondite
Garnierite
Willemsite

125.  In nickel hydrosilicates, nickel replaces the Mg atoms
 Replacement occurs in serpentine, talc and chlorite
 Garnierite is a group name for nickel hydrosilicates
 Garnierites have the crystal structure of serpentine, talc, or
chlorite
 Garnierites are largely of supergene origin
 Garnierites occur as fillings in open spaces or as coatings in joint
and fracture surfaces
 Garnierites range in colour from green (light and dark), to yellow-
green, to light blue and turquoise blue. Dark green varieties carry
more nickel

126. SiO2 MgO FeO NiO
New Caledonia, sample-1 53.0 18.1 0.1 20.9
New Caledonia, sample-2 49.0 18.9 0.2 21.7
New Caledonia, sample-3 53.2 15.0 0.0 24.5
New Caledonia, sample-4 49.8 13.5 0.2 29.2
New Caledonia, sample-5 37.4 2.7 0.3 49.6
Morro do Cerisco, Brazil 43.7 30.4 5.5 5.5
Morro do Niquel, Brazil 52.9 18.3 0.2 16.8
Riddle, Oregon, USA 47.8 18.6 0.1 19.6
Riddle, Oregon, USA 52.3 16.3 n.a. 20.8

127.  Serpentine Minerals
 Chrysotile
 Amphibole Minerals
 Tremolite-Actinolite
 Crocidolite
 Cummingtonite

128. AMPHIBOLE MINERALS
Fe
Mg
Ca
Na
H2Mg7Si8O24 H2Fe7Si8O24
Calcic amphiboles
Actinolite Ferro
Actinolite
Cummingtonite Grunerite
Sodic amphiboles
Tremolite
H2Ca2Mg5Si8O24
H2Ca2Fe5Si8O24
Glaucophane
H2Na2Mg3Al2Si8O24
Riebeckite (Crocidolite)
H2Na2Fe5Si8O24
H2Ca7Si8O24
H2Na14Si8O24

129. Tigereye: Silica replacing crocidolite amphibole

131. High Density
Bedrock zone
Variable Density
Saprolite zone
Ferruginous
zone
Bulk Density
Depth
Top
Bottom
Intermediate
zone
Ferricrete /
Silcrete

132. Run-of-mine
Wt.% / Ni
Reject
Wt.% / Ni
Recovered
Wt.% / Ni
Ni
upgrading
Sorowako W. Block
-1” ore type
100%
1.09% Ni
65%
0.6% Ni
35%
2.0% Ni 83%
Sorowako E. Block
-1” ore type
100%
1.33% Ni
55%
1.03% Ni
45%
1.7% Ni 28%
Sorowako E. Block
-6” ore type
100%
1.51% Ni
23%
0.89% Ni
77%
1.7% Ni 13%
Sorowako E. Block
-18” ore type
100%
1.59% Ni
14%
0.9% Ni
86%
1.7% Ni 7%
Bulong
High upgrading ore
100%
1.60%
25%
0.94% Ni
75%
1.82% Ni 14%
Bulong
Low upgrading ore
100%
1.58% Ni
14%
0.85%
86%
1.7% Ni 7%
Vermelho
-100# fraction
100%
0.8% Ni
49.6%
0.34%
50.4%
1.25% Ni 56%

133. 0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
0 10 20 30 40 50 60 70 80 90 100
QUANTITY OF REJECT, wt%
UPGRADING
INDEX
Values of Upgrading Index are based on a
constant Head Grade of 1.0%Ni with variable
quantity of rejects (X-axis) and variable grade of
rejects (different curves).
0.1
0.0
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0

134. P.T. INCO
Saprolite zone
Ferruginous zone
Bedrock
Forms of nickel in the laterite profile
Nickel as hydroxide essentially in the
goethite-limonite structure. Some Ni
adsorbed by Mn-Hydroxides.
Nickel as hydro-silicate essentially with
the talc-serpentine-clay lattice structure:
Nickel talc
Nickel serpentine
Nickel smectites
Nickel as silicate essentially in the ferro-
magnesian minerals, as ionic
replacement of Mg and Fe atoms:
Olivine
Pyroxene
Serpentine

136.  Nickel grade; cobalt grade
 Resource tonnage / Life of Mine / scale of operation
 Ore chemistry and mineralogy
 Ore consistency
 Upgradeability of ore
 Process selection
 Availability of cheap power supply
 Selection of fuel
 Availability of raw materials: water, silica flux, aggregate
 Availability of infrastructure
 Location of project
 Mining method
 Environmental considerations
 Negotiations with local and central governments
 Funding of the project
 Selection of engineer and contractor

137.  Political risk
 Bureaucracy
 Regulatory framework (environmental, legal)
 Taxation, royalties
 Slow ramp-up rates
 Energy costs
 Depressed metal prices
 Processing risk
 Construction risk
 Financial elements: interest rates, exchange rates
 Environmental regulations: lower thresholds

138. New Projects:
 Goro Nickel, New Caledonia 54 k
 Onca-Puma, Brazil 25 k
 Ravensthorpe, Australia (QNI) 50 k
 Ramu River, PNG
Expansions:
 Sorowako, Indonesia 22 k
 Doniambo, New Caledonia 15 k
 Murrin-Murrin, Australia 10 k
Under
Construction

139. New Projects:
 Koniambo, New Caledonia 54 k
 Vermellho, Brazil 45 k
 Ambatovy, Madagascar 40 k
 BarroAlto, Brazil 20 k
 Fenix (Skye), Guatemala 20 k
 Sorowako HPAL, Indonesia 20 k
 Pomalaa HPAL, Indonesia 20-45
Expansions:
 Coral Bay, Philippines 15 k
 Moa Bay, Cuba 17 k
 Loma de Niquel,Venezuela 17 k

140. New Projects:
 Bahodopi, Indonesia
 Gag Island, Indonesia
 Weda Bay, Indonesia
Expansions:
 Goro, New Caledonia
 Sulawesi, Indonesia
 Onca-Puma, Brazil
 Cuba

142.  Pyrometallurgical processing
(Ore is melted)
 Production of Ferro-nickel
 Production of Ni-S matte
 Hydrometallurgical processing (Leaching by acid)
 PAL (Pressure acid leaching) – HPAL
 EPAL (Enhanced Pressure Acid Leaching
 AL (Atmospheric Leaching)
 Heap Leaching
 Combined pyro and hydro process (Caron)
(Ore is reduced at high temperature, then leached)

143. Project Owner Country Remarks
Cerro Matoso BHP-B Columbia
Codemin Anglo Brazil
Doniambo SLN/Eramet New Caledonia
Exmibal Ex. Inco Guatemala Mothballed
Falcondo Falconbridge Dominican Rep.
Fenimark FENI (govt.) Macedonia Closed
Hyuga Sumitomo Japan Imported ore
Larymna Larco Greece
Loma de Hiero Anglo Venezuela
Morro do Niquel Anglo Brazil Closed
Oheyama Nippon Yakin Japan Imported ore
Onca-Puma Vale Inco Brazil
PAMCO Nippon Steel Japan Imported ore
Pomalaa ANTAM Indonesia Some imported ore

144. Project Owner Country Remarks
Sorowako PT Inco Indonesia
Doniambo SLN/Eramet New Caledonia

145. Project Owner Country Remarks
Moa Bay Cuba Niquel Cuba First HPAL
Bulong Australia Shut down
Cawse Norilsk Australia
Murrin-Murrin Minara Australia
Coral Bay Sumitomo Philippines
Goro Vale Inco New Caledonia Under construction
Ramu River PNG Under construction
Ravensthorpe BHP-B Australia Under construction

146. Project Owner Country Remarks
Nicaro Union del Niq Cuba
Punta Gorda Union del Niq Cuba
Nonoc Philippines Closed
QNI BHP-Billiton Australia Imported ores
Tocantins Niquel Toc. Brazil

147. Project Owner Country Remarks
Caldag European
Nickel
Turkey First Heap Leach
project
Ravensthorpe BHP-B Australia Part of flow sheet
Murrin-Murrin Minara Australia Expansion of
project
Piaui Vale Brazil Being fast-tracked
for production

148. Ferro-Nickel Process
Upgrading in the mine
Drying of ore
Upgrading after drying
Calcining
Electric Furnace Smelting
Refining Furnace
Ferro-Nickel Product
20 – 50% Ni
Nickel-Matte Process
Upgrading in the mine
Drying of ore
Upgrading after drying
Calcining
Electric Furnace Smelting
Converting
Nickel-Matte Product
78% Ni

149. Important concerns:
 Slag should not attack refractory (S/M ratio)
 Melting temperature should be suitable (S/M;
Fe)
 Olivine should not be introduced to the furnace
 Appropriate reduction of ore prior to smelting
 Ni/Fe ratio in the ore for ferro-nickel operation

150. Ore Preparation: wetting, screening
Pre Heating through flash steam
Pressure Acid Leach in autoclave
Heat recovery from leached pulp
CCD thickening and washing
Neutralisation of pregnant solution
Precipitation of metals by adding H2S/alkali
Solid/liquid separation
Ni/Co products as mixed sulphides, oxides, hydroxides

151. Important concerns:
 Amounts of soluble Mg and Al in ore (acid consumers)
 Acid to ore ratio required for process
 Minimum operating temperature required to leach
 What is the appropriate pressure during leaching
 Retention time in the autoclave
 Rheological behaviour during slurrying
 How to recover metals in the back end of processing
 What product to make

152. Ore Preparation: screening, upgrading
Drying, using oil or coal
Grinding
Reduction, using CO/H2
Ammonia leaching
CCD thickening and washing
Stripping, using steam
Calcining of Ni/Co precipitate
Sintering of calcine
Nickel oxide product

153. Nickel Sulphide Nickel Laterite
Mining Hard rock mining more
expensive. Many sulphides U/G
Soft rock mining cheap.
Only open cast mining
Deposit
uniformity
More uniform in chemistry and
mineralogy
More varied in chemistry
and mineralogy; stratified
Upgrading Highly upgradeable to sulphide
concentrate
Low upgradeability. Final
grade generally <2.0% Ni.
Ore/Con
shipping
Relatively cheap (per lb Ni) due
to high upgradeability
Relatively high (per lb Ni)
due to low upgradeability
Processing cost Modest due to high Ni content.
Sulphur provides latent heat.
High due to low Ni content.
High energy input required.
Ni recovery High due to consistency of ore
chemistry and mineralogy
Modest due to compromise
for prevalent chemistry
Capital cost Modest per lb of Ni High per lb of Ni
Project size/life Can be short to medium Long to pay for high capital

155. 6,600,000 Hectares
PT INCO — Original Concession area

159. -1” +1-6” +6-18” +18”
18” ore
(90% Rec.)
Ore
55%
Ore
20%
Ore
15%
Reject
10%
6” ore
(75% Rec.)
Ore
55%
Ore
20%
Reject
15%
Reject
10%
1” ore
(55% Rec.)
Ore
55%
Reject
20%
Reject
15%
Reject
10%
1” Hi Oliv.
(55% Rec.)
Ore
55%
Reject
20%
Reject
15%
Reject
10%
1” Lo Oliv.
(75% Rec.)
Ore
55%
Ore
20%
Reject
15%
Reject
10%
Screen recoveries given on wet basis

160. Packing
E.L E.L E.L
ESP
THICKENER
Scrubber
500 T
BIN
100 T
BIN
ESP
M.C
Slag to Disposal area (1500°C)
Furnace Matte (1350°C)
Electric Furnace
Silica Flux
Scrap
Converter
Matte Cast
Hot Calcine (700°C)
Wet Ore Stockpile
Dryer Kiln
Reduction Kiln
Recycle
to Dryer
Slurry
Dry Dust
Pugmill
Dust
Market
Fluid Bed
Stack
HSFO
Air
Granulation
HSFO
Air
Liquid Sulphur
Dry Dust
DKP
Dried Ore Storage
Rock
West Block (Reject)
East Block (Crushed)
Hot Gas
Water (Hi pressure)
Granulated
Matte
Oversize
(Recycle to Converter)
M.C
Air
Product Dryer
Simplified Process Plant Flow Sheet

161. WET ORE STOCKPILE

162. For efficient operation smelter feed must meet
the following requirement:
 S/M ratio 1.95 – 2.15 (optimum level of
2.05)
 Iron content 20 – 23% Fe (optimum level of
21.5%)
 Olivine content of <22% in any East Block batch

163. Packing
E.L E.L E.L
ESP
THICKENER
Scrubber
500 T
BIN
100 T
BIN
ESP
M.C
Slag to Disposal area (1500°C)
Furnace Matte (1350°C)
Electric Furnace
Silica Flux
Scrap
Converter
Matte Cast
Hot Calcine (700°C)
Wet Ore Stockpile
Dryer Kiln
Reduction Kiln
Recycle
to Dryer
Slurry
Dry Dust
Pugmill
Dust
Market
Fluid Bed
Stack
HSFO
Air
Granulation
HSFO
Air
Liquid Sulphur
Dry Dust
DKP
Dried Ore Storage
Rock
West Block (Reject)
East Block (Crushed)
Hot Gas
Water (Hi pressure)
Granulated
Matte
Oversize
(Recycle to Converter)
M.C
Air
Product Dryer
Drying Operation
Screening of dried ore at 3/4“ screen
- 3/4“ + 3/4“
West Block type Product.
Saved as Ore
Reject.
Discarded
East Block type Product.
Saved as Ore
Crushed.
Added to Ore

164. DRYER

165. Packing
E.L E.L E.L
ESP
THICKENER
Scrubber
500 T
BIN
100 T
BIN
ESP
M.C
Slag to Disposal area (1500°C)
Furnace Matte (1350°C)
Electric Furnace
Silica Flux
Scrap
Converter
Matte Cast
Hot Calcine (700°C)
Wet Ore Stockpile
Dryer Kiln
Reduction Kiln
Recycle
to Dryer
Slurry
Dry Dust
Pugmill
Dust
Market
Fluid Bed
Stack
HSFO
Air
Granulation
HSFO
Air
Liquid Sulphur
Dry Dust
DKP
Dried Ore Storage
Rock
West Block (Reject)
East Block (Crushed)
Hot Gas
Water (Hi pressure)
Granulated
Matte
Oversize
(Recycle to Converter)
M.C
Air
Product Dryer
Reduction Operation
Diameter, m Length, m Throughput, Wmt / Hr
Kiln 1 5.5 100 145
Kiln 2 5.5 100 145
Kiln 3 5.5 100 145
Kiln 4 6.0 115 190
Kiln 5 6.0 135 215

166. REDUCTION KILN
REDUCTION
KILN FEED

167. 1 2 3 4 5 6
1300
1400
1500
1600
1700
20%
FeO
25%
FeO
30%
FeO
Silica / Magnesia Ratio
T°C
1979
Current
LIQUID
SOLID

168. 18 m
Matte
Refractory bricks on
Sidewalls & hearth
Slag
Matte
Slag
Copper “fingers”
(water cooled)

169. 18 m
Matte
Refractory bricks on
Sidewalls & hearth
Slag
Matte
Slag
Copper “fingers”
(water cooled)
Olivine mush
causing ineffective
heat transfer

170. Packing
E.L E.L E.L
ESP
THICKENER
Scrubber
500 T
BIN
100 T
BIN
ESP
M.C
Slag to Disposal area (1500°C)
Furnace Matte (1350°C)
Electric Furnace
Silica Flux
Scrap
Converter
Matte Cast
Hot Calcine (700°C)
Wet Ore Stockpile
Dryer Kiln
Reduction Kiln
Recycle
to Dryer
Slurry
Dry Dust
Pugmill
Dust
Market
Fluid Bed
Stack
HSFO
Air
Granulation
HSFO
Air
Liquid Sulphur
Dry Dust
DKP
Dried Ore Storage
Rock
West Block (Reject)
East Block (Crushed)
Hot Gas
Water (Hi pressure)
Granulated
Matte
Oversize
(Recycle to Converter)
M.C
Air
Product Dryer
• Converter Matte is cast, granulated with water sprays, dried,
screened, packed into 3-tonne polypropylene cloth bags,
and shipped to the client in Japan
• Average Product analysis: 78% Ni
1-2% Co
20% S
Converting, Granulating, Packing,
Shipping

171. E. Block
Ore
W. Block
Ore
RKF Calcine EF
Slag
EF
Matte
Product
SiO2 34.7 37.1 36.1 40.8 47.7
MgO 20.7 15.4 18.1 18.9 22.2
Fe2O3 27.7 32.0 30.0 29.2 25.9 Fe=61.5 Fe=0.5
FeO All iron reported as Fe2O3
Al2O3 3.12 2.53 2.92 2.77 3.02
Cr2O3 1.42 1.87 1.64 1.68 1.78
MnO 0.53 0.63 0.57 0.57 0.66
NiO 1.80 2.60 2.44 2.57 0.19 Ni=27.5 Ni=78.5
CoO 0.08 0.10 0.09 0.09 0.03 Co=0.76 Co=1.2
CaO 0.32 0.46 0.39 0.45 0.50
LOI ? ? ? 0.0 0.0 S=9.2 S=19.7
Total 90.86 92.69 92.25 97.03 101.98 98.96 99.90

173.  Eksplorasi nikel laterite merupakan salah satu
usaha bisnis yang berisiko tinggi.
 Diperlukan konsep dan strategi yang matang
serta personil yang berpengalaman untuk
menjalankan bisnis tersebut.
 Keberhasilan bisnis diukur dari cara
mengelola tingkat resiko dengan cara/
metode yang efektif dan efesien

174.  Apa definisi eksplorasi dan Strategi eksplorasi
 Kenapa strategi dan managemen eksplorasi itu
penting?
 Aspek apa saja yang mempengaruhi dalam
menyusun strategi eksporasi
 Strategi eksplorasi meliputi apa saja?
 Bagaimana mengelola eksplorasi sebagai bisnis
yang berisiko tinggi menjadi sesuatu yang
menguntungkan
 Bagaimana mengimplementasikan strategi
eksplorasi untuk cebakan nikel laterite.

175.  Secara khusus definisi Eksplorasi Geologi
(Koesoemadinata,_) adalah :
 “Suatu aktifitas untuk mencari tahu keberadaan
suatu objek geologi di suatu daerah atau ruang
yang sebelumnya tidak diketahui keberadaannya.
Objek geologi yang dimaksud terutama komoditi
potensi bahan galian seperti cebakan mineral,
batubara, minyak dan gas bumi ataupun air tanah.
Selain itu objek geologi dapat berupa gejala geologi
yang bermanfaat atau memiliki dampak negatif
seperti: patahan, data batuan untuk keperluan
konstruksi sipil dll.”.

176.  “Suatu keahlian dalam perencanaan dan dan
pengarahan kegiatan eksplorasi yang berskala besar
dalam bentuk tahapan-tahapan yang efektif dan efisien
untuk mencari daerah yang favorable akan terdapatnya
cebakan mineral ekonomis”.

177.  Kegiatan eksplorasi adalah kegiatan usaha ekonomi yg beresiko
tinggi (geologi, teknologi, ekonomi dan politik)
 Paradigma eksplorasi yang tumbuh seiring dengan resiko yang
ada
• Dalam kegiatan eksplorasi sangat diperlukan pentahapan dimana pada akhir
suatu tahap dilakukan pengambilan keputusan dilanjutkan atau tidak.
• Peluang yang lebih besar tergantung pada kerapatan data, teknologi yang lebih
tinggi, personil yang lebih banyak dan waktu yang lebih lama
• Keseluruhan faktor tersebut berbanding lurus dengan biaya yang dibutuhkan
 Paradigma tersebut merupakan dasar dalam menyusun Strategi
eksplorasi untuk
 Menentukan urutan kegiatan eksplorasi,
 Memperbesar peluang keberhasilan
 Memperkecil resiko kegagalan

178. • Peluang atau probabilitas / Success ratio
• Pertaruhan dengan resiko yang sangat tinggi
• Parameter geologi (model dan kriteria geologi)
• keberadaan data yang merupakan situasi sesaat.
• Kegagalan salah satu aktifitasnya.

179.  Penentuan tahapan-tahapan eksplorasi
 Penentuan metode pada setiap tahapan
 Penentuan target atau hasil yang diharapkan
dari setiap tahapan
 Penentuan desain eksplorasi dalam setiap tahapan
 Penentuan personil, peralatan dan biaya dari
setiap tahapan

180. TAHAPAN EKSPLORASI
Catatan :
Dalam penilaian daerah
prospek hanya didasar-
kan kepada
pertimbangan aspek
geologi saja
STUDI KELAYAKAN, AMDAL & PERENCANAAN TAMBANG
TAHAP EKSPLORASI PENDAHULUAN (RECONNAISSANCE)
Lingkup pekerjaan : studi pustaka, pemetaan geologi skala 1:50.000, pengambilan conto, pembuatan sumur uji (jika dipandang perlu)
dan analisa conto
TIDAK PROSPEK
TAHAP EKSPLORASI SEMI DETIL
Lingkup pekerjaan : pemetaan geologi dan topografi skala
1:5.000/ 1:10.000, pengambilan conto, pembuatan sumur uji (jika
diperlukan), pemboran pandu, survey geofisika dan geokimia,
analisa laboratorium.
PROSPEK
DISEBAGIAN WILAYAH
EVALUASI
Evaluasi Geologi Permukaan &
Bawah Permukaan-Semi Detil
TAHAP EKSPLORASI DETAIL
Lingkup pekerjaan : pemetaan geologi dan topografi skala 1:1.000/1:2.000, pengambilan conto, pemboran detil,
survey geofisika dan geokimia, analisa laboratorium, penelitian geologi teknik
Evaluasi Geologi Permukaan & Bawah Permukaan - Detil
Dilanjutkan
Dilanjutkan
DAERAH KETERDAPATAN/KP. EKSPLORASI
JIKA DATA-DATA GEOLOGI CUKUP
MEMADAI (kerapatan datanya)
LOKASI TAMBANG/ KP. EKSPLOITASI
TAHAPAN STUDI LITERATUR DAN SITE VISIT
STOP
PENYELIDIKAN TIDAK
DILANJUTKAN

181.  Membuat strategi eksplorasi dan menjalankan
secara konsisten, efektif dan efesien dengan
mengurangi resiko
 Memahami secara utuh model geologi daerah
eksplorasi
 Improvisasi dan kompetensi geologist berperan
dalam proses evaluasi dan peningkatan tahapan
eksplorasi selanjutnya.
 Pengelola eksplorasi (Manager proyek) harus
memiliki wawasan tentang orientasi bisnis
perusahaan, perkembangan teknologi eksplorasi
dan kebutuhan pasar komoditi

182.  Memahami karakteristik dan model geologi nikel laterite
 Memahami spesifikasi bijih untuk kebutuhan pasar
(market deman) maupun untuk rencana pembuatan
pabrik (pig iron, limonite ore dan high grade saprolite ore)
 Membuat strategi eksplorasi yang efektif dan efisien
untuk nikel laterite (tahapan, metode, target, personil dan
peralatan)
 Melaksanakan strategi eksplorasi secara konsisten dan
melakukan kontrol terhadap kualitas dan kuantitas data
yang dihasilkan/
 Memaksimalkan data evaluasi geologi untuk perencanaan
tahapan berikutnya

183.  Ada 3 jenis spesifikasi bijih nikel laterite yang
diperdagangkan secara umum
 Pig Iron (Ni 1.2 – 1.4; Fe > 45%
 Limonite ore (Ni 1.5 ; Fe 35%
 High Grade Saprolite ore (Ni> 1.9%

184. DATABASE REVIEW
EXPLORATION
TARGETTING
RECONNAISSANCE
TESTPITTING
SAMPLING &
ASSAYING
DRILLING PROGRAM
GEOEVALUATION AND
REPORT ING

185.  To Located the landform characteristic based on :
 Aerial photograph (smaller map scale)
 landsat imagerial (Regional view)/Satellite
 Aster Image
 Access recognition
 Cultivated Boundary
 Open space area recognition.
 Structural geology dan lithology interpretation.

187. Significant Zn anomalies and Minor Cu Pb anomalies
TARGETING PROSPECTING -
ASTER IMAGING ANALYSIS
The green color that
represent Magnetit-
Chromite mineral has
showing good indication
Key objective : Preliminary
observation of lithology (ultramafic,
sediment, limestone, etc), alteration
(clay, silicic, laterite, gossans),
structure geology, lineament,
morphology, drainage and vegetation
anomaly for defining further
exploration target.

188.  Digitizing from old data
 Aanalyzing and evaluation for
previous data collected
 Map Overlay and combining and
extraction for target selection
Exploration
Target
Criteria :
 Slope and landform identification from landsat or
aerial photograph
 Geological Condition
 Drainage system
 Undulating Topography
 Good Laterite Profile (define from previous testpit
recognition)

189.  Preliminary visit to confirm the
lithology and morphology of
the target area.
 To confirm the accessibility of
the target area.

190.  To define the geological condition I.e,
lithology, structure, serpentinization
and iron crust distribution.
 Outcrop observation
 Float mapping
 Structural geology (fault, joint, fold)
 Surface Sampling (assay, thin section
Float Mapping
Outcrop observation
GPS Reading

192.  The pit location was selected ramdomly base on topography interpretation
 Tespit dimension 1.5m x 1.25 m
 To provide large samples for more accurate tonnage factor and ore type fraction.
 To understand the actual laterite profile characteristic
Weighing
Quartering
Enter the
Hole
Transfer Material to
surface
Bottom Pit

193.  First phase core drilling for 400m stagger
 Secod phase core drilling for 200 m regular spacing
 Using Jacro rig with HQ size tripple tube
 Objective to understand ore continuity, thickness,
chemistry distribution for resource estimation
Critical Issues:
- Quality of sample (core recovery)
-- Accuracy (deptth, interbal, etc)

194.  Core logging
 Screening and Fractination
 Weighing
 Reduction sampling
 Numbering and labelling
Screening
Weighing Reduction
Sample
Labeling/
Packing
Core Logging

195.  QAQC Program is mandatory for exploration
drilling projects which will be reported under NI
43-101.
 The QAQC program is to ensure a consistently
high quality work that will maintain public
confidence and assist securities regulators, at
any stage of project from pre-feasibility,
feasibility and operating mine.
 This guidelines is to be implemented for
exploration and the lab. Based on this, MRMR
document will more reliable and in line with
current industry practice

196. Precision = Cluster
Accuracy = closeness to target
Bias = difference from target
Good
Accuracy &
Precision
Good Precision,
Bias
Poor Precision,
good accuracy
Poor Precision
Poor accuracy
Quality Assurance (QA)  Setup system (all those planned or systematic actions
necessary to provide adequate confidence that a product or service will satisfy given
needs.
 Establishment of systems and standards
 Ensure quality
QualityControl (QC)  Implementation (assurance in the quality context is the relief of
concern about the quality of product. Sampling plans and audits, the quality control
devices, are designed to supply part of this assurance
 use of statistical tools and checks (duplicate, standard, blank, check assay and repetition)
 ensure the systems are in statistical control

197.  To control the preparation samples during splitting /reduce samples.
 Using for calculate precision (average difference between samples)
and bias (repeatability between the duplicate pairs)
 Consists of :
-Wet Duplicate
- Splitter Duplicate
- Pulp Duplicate
Drilling
Preparation
(Wet splitting)-
Wet Duplicate
Preparation
(Boyd splitting)-
Splitter Duplicate
Preparation
(CRM splitting)-
Pulp Duplicate
Lab Assaying
Pulp Duplicate
Contribute Error
Wet Dup
20 %
Splitter Dup
15 %
Pulp Dup
10 %
Pulp Dup
3 %

198. y=x
R2
=1
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
Original Sample
Duplicate
sample
Scatter Plot - Ni (%)
y = 0.992x + 0.0091
R2
= 0.9854
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5 3 3.5
Original Ni (%)
Duplicate
Ni
(%)
Ideal
Scatter Plot
-50
-40
-30
-20
-10
0
10
20
30
40
50
0.00 1.00 2.00 3.00 4.00
Average
Rel
Diff
%
Rel Diff Cr
PTI SH's Wet Duplicate Samples - Ni
Cumulative Frequency of the Relative Error
Estimate of Precision
0%
10%
20%
30%
40%
50%
60%
70%
80%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Relative difference Plot Cumulative Precision Plot

199.  Certified references material or in- house standard.
 Value is known
 Allows assessment of accuracy and bias
 Purpose of standards:
▪ Ensure accuracy of results
▪ Ensure required analytical precision – mechanical failure
▪ Ensure there is no bias
Ni (QC SAPO)
1.90
1.95
2.00
2.05
2.10
2.15
2.20
Bias in Ni Sap Ore, but still in
acceptable range of 3SD
Standard Sample Monitoring

200.  Samples with grade less than the limit detection.
 Blank sample measure the contamination cleanliness in sample
preparation
 Also need to be able to compare results with immediately preceding
laboratory analyzed sample (develop QAQC program)
 Blank materials are better in silica sand, but granite and granodiorite
as much better.
Ni (SPL Blank New )
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Blank Sample Monitoringc

201.  Check Assay is precision check to compare analysis data between
primary lab and secondary lab
 To send 3 – 5% samples/month to External lab for checks.
 Repetition is precision check to control the lab instruments (XRF)
and to control backup sample (Pulp Storage)
 To send 30 samples/week to External Lab.
Repetition Samples
y = 0.9847x + 0.009
R2
= 0.9941
0
1
2
3
4
5
0 1 2 3 4 5
Ni % Previous result
Ni
%
Current
Result
Ni Comparison
y = 0.9839x + 0.0132
R2
= 0.9943
0
1
2
3
4
5
6
7
0 1 2 3 4 5 6 7
PTI Lab
Intertek
Lab
Check Assay Repetition Sample

202. DATA COMPILATION
 To collect all the data I.e field data, laboratory, logging and store in
database format
 Integrating the information from the various data.
 Mostly store in digital data
DATAVALIDATION
 Data Clean-Up, to make sure the data are ready to use and do not
contain an error, I.e:
 Coordinat and grid check (drill and test pit)
 Miss type of Assay value and logging data
 Hole and sample number check
 To combine the spread sheet assay data with location where sample was
taken

203. Horisontal Scale : BH_73 – BH_119
Vertical Scale 1 : 4
High Grade Ore

204.  Evaluasi geologi adalah salah tahapan penting dalam kegiatan eksplorasi dimana
hasil evaluasi ini akan menentukan tahapan apakah suatu kegiatan eksplorasi
prospek untuk dilanjutkan/ ditingkatkan atau tidak
 Setiap peningkatan tahapan eksplorasi akan memberikan konsekuensi biaya
yang sangat besar sehingga keputusan prospek atau tidak suatu wilayah
eksplorasi harus dilakukan secara akurat dan komprehensif.
 Tujuan akhir dari suatu kegitan eksplorasi adalah
 Mengetahui berapa besar nilai ekonomi dari endapan bahan galian disuatu daerah
 Diketahui berapa banyak, besar dan kuantitas, kualitas endapan bahan galian
 Besarnya, kuantitas dan kualitas dinyatakan sebagai cadangan bahan tambang.
 Evaluasi geologi meliputi beberapa tahapan
 Kompilasi data geologi dan penysunan database geologi
 Validasi database geologi dan akuisisi data
 Pengolahan data dan perhitungan cadangan
 Pembuatan laporan sumberdaya dan cadangan

205. Titik Bor Easting Northing FR TO Length Ni co fe soi2 CaO Mgo
Geo
Layer
Ore Layer
BH_178 510198,92 9911099,2 0,00 1,00 1,00 0,74 0,06 41,60 7,25 <0.01 0,83 LIM OB
BH_178 510198,92 9911099,2 1,00 2,00 1,00 0,79 0,09 42,10 6,71 <0.01 0,86 LIM OB
BH_178 510198,92 9911099,2 2,00 3,00 1,00 0,95 0,09 43,20 6,95 0,01 1,98 LIM OB
BH_178 510198,92 9911099,2 3,00 4,00 1,00 1,19 0,09 37,70 16,70 0,05 5,46 LIM OB
BH_178 510198,92 9911099,2 4,00 5,00 1,00 1,51 0,04 16,40 38,80 0,32 22,20 SAP OB
BH_178 510198,92 9911099,2 5,00 6,00 1,00 2,12 0,03 11,70 10,90 0,17 27,20 SAP HGO
BH_178 510198,92 9911099,2 6,00 7,00 1,00 2,18 0,03 12,40 38,70 0,17 26,80 SAP HGO
BH_178 510198,92 9911099,2 7,00 8,00 1,00 2,44 0,03 12,80 38,10 0,16 26,80 SAP HGO
BH_178 510198,92 9911099,2 8,00 9,00 1,00 2,38 0,04 13,80 36,70 0,18 25,30 SAP HGO
BH_178 510198,92 9911099,2 9,00 10,00 1,00 1,60 0,02 8,56 41,20 0,31 32,70 SAP BZ
BH_178 510198,92 9911099,2 10,00 11,00 1,00 1,38 0,03 10,30 41,60 0,26 29,60 SAP BZ
BH_178 510198,92 9911099,2 11,00 12,00 1,00 1,33 0,03 12,80 42,40 0,38 24,20 SAP BZ
BH_178 510198,92 9911099,2 12,00 13,00 1,00 1,18 0,03 10,60 42,40 0,23 28,10 SAP BZ

206. Titik Bor Easting Northing FR TO Length Ni co fe soi2 CaO Mgo
Geo
Layer
Ore Layer
BH_183 510201,17 9910851,3 0,00 1,00 1,00 0,64 0,04 39,20 6,97 <0.01 0,59 LIM OB
BH_183 510201,17 9910851,3 1,00 2,00 1,00 0,80 0,10 40,60 5,90 <0.01 0,60 LIM OB
BH_183 510201,17 9910851,3 2,00 3,00 1,00 0,95 0,14 45,60 3,14 <0.01 0,80 LIM OB
BH_183 510201,17 9910851,3 3,00 4,00 1,00 1,36 0,09 45,50 5,98 <0.01 2,15 LIM LGO
BH_183 510201,17 9910851,3 4,00 5,00 1,00 1,48 0,09 46,20 4,80 <0.01 1,79 LIM LGO
BH_183 510201,17 9910851,3 5,00 6,00 1,00 1,60 0,13 46,40 3,56 0,10 1,16 LIM LGO
BH_183 510201,17 9910851,3 6,00 7,00 1,00 1,51 0,16 42,00 9,95 <0.01 3,95 LIM LGO
BH_183 510201,17 9910851,3 7,00 8,00 1,00 1,33 0,12 46,20 5,53 0,01 1,46 LIM LGO
BH_183 510201,17 9910851,3 8,00 9,00 1,00 1,35 0,09 35,30 23,80 0,01 4,42 LIM MGO
BH_183 510201,17 9910851,3 9,00 10,00 1,00 1,70 0,08 39,00 16,30 0,01 3,42 LIM MGO
BH_183 510201,17 9910851,3 10,00 11,00 1,00 1,67 0,10 40,10 11,40 0,04 5,46 LIM MGO
BH_183 510201,17 9910851,3 11,00 12,00 1,00 1,68 0,07 29,80 23,50 2,06 10,60 SAP MGO
BH_183 510201,17 9910851,3 12,00 13,00 1,00 1,42 0,04 17,70 35,90 2,62 21,70 SAP BZ
BH_183 510201,17 9910851,3 13,00 14,00 1,00 0,88 0,03 10,80 40,50 1,14 33,20 SAP BZ
BH_183 510201,17 9910851,3 14,00 15,00 1,00 1,03 0,03 14,10 38,30 1,22 27,30 SAP BZ
BH_183 510201,17 9910851,3 15,00 16,00 1,00 1,21 0,03 9,98 47,40 0,49 26,00 SAP BZ
BH_183 510201,17 9910851,3 16,00 17,00 1,00 1,67 0,02 7,96 44,20 0,33 30,00 SAP BZ
BH_183 510201,17 9910851,3 17,00 18,00 1,00 1,35 0,02 8,92 41,10 0,40 33,00 SAP BZ
BH_183 510201,17 9910851,3 18,00 19,00 1,00 0,97 0,02 9,31 42,50 0,47 31,40 BRK BZ
BH_183 510201,17 9910851,3 19,00 20,00 1,00 0,39 0,02 6,72 41,70 0,17 35,50 BRK BZ
BH_183 510201,17 9910851,3 20,00 21,00 1,00 0,22 0,02 5,77 41,10 0,09 37,50 BRK BZ

207.  Metode perhitungan coventional (Geometrik)
 Section
 Isochore
 Poligonal
▪ Included area
▪ Extended area (regular grid)
▪ Triangle
▪ Bi-sect polygon
 Metode perhitungan Moderen (geostatistik)
 Linear regresion
 Inverse distance
 Kriging

209.  Strategi eksplorasi adalah sangat penting dan
merupakan kunci keberhasilan dalam
kegiatan eksplorasi
 Kegiatan eksplorasi yang dikelola dengan
baik akan memberikan hasil yang optimal,
efektif dan efesien serta mengurangi resiko
yang timbul
 Evaluasi geologi merupakan kunci layak
tidaknya suatu tahapan eksplorasi untuk
dilanjutkan atau tidak.

210. TerimaKasih
Contact Person : Suharto
HP : 08124244871
Email : suharto_mks@yahoo.com