EXPO2005. 1. 20th WORLD MINING CONGRESS & EXPO2005. 7 â 11 NOVEMBER 2005, TEHRAN, IRAN. âMining and Sustainable Developmentâ ...
20th WORLD MINING CONGRESS & EXPO2005 7 – 11 NOVEMBER 2005, TEHRAN, IRAN “Mining and Sustainable Development”
20th WORLD MINING CONGRESS & EXPO2005
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Modelling of sedimentary deposits of Kaolin clays, in continental environment: application to the Charentes deposits, France Jean-Pierre Rolley Mohammad Koneshloo Marc Vinches CMGD, Ecole des Mines d'Alès,France 20th WORLD MINING CONGRESS & EXPO2005
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Presentation Plan • Introduction The world of Kaolin
Geographic and geological setting of the deposit
• Traditional Method Deposit product • The Analysis of Data & Situation • Discussion & Conclusion
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What is a kaolin? kaolin : Rock composed of kaolinites group minerals Kaolinite, Dickite, Nacrite, and Halloysite
A 7 °A: Kaolinite
Alteration Aluminosilicates
A 10 °A:
Clays
Illite
Hydrothermal Process
A 14 °A: A pseudo-Sheets and Fiberous Facies 20th WORLD MINING CONGRESS & EXPO2005
Chlorites Smectites
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Rainin g
Marine sedimentation
Continental sedimentatio n
Hydro20th WORLD MINING CONGRESS & EXPO2005
Therma l
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KAOLINITIQUE BASSIN of CHARENTES In the north of
Aquitain Bassin « terres blanches » means « white soil »
Various properties for application in different industries. 20th WORLD MINING CONGRESS & EXPO2005
Ref: www.ign.fr
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Geological Setting
Geological map of the Charente Basin area. The kaolin quarries are located where the sand overburden does not exceed 30m. 20th WORLD MINING CONGRESS & EXPO2005
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Geological sections showing the distribution of the kaolinite layers
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AGS MINERAUX • •
Deposit
European leader in the production of calcined kaolin Key Numbers 2002 Annual turn-over:43 million Euros Annual production :743 KT Work force :305 Persons
Extraction
Crushing
Calcination
and grinding 20th WORLD MINING CONGRESS & EXPO2005
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Source of data : Drilling
Core Recuperation
Choice of clay parts
Large Grid
Small Grid
Creation of Data Base Definition of parametres to be analysed
Choice of the blocks based on core drilling data
Preparation of samples for analysis Survey of variations on the site Analysis of Samples 20th WORLD MINING CONGRESS & EXPO2005
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To Be OR NOT TO BE, Representativity ? 20th WORLD MINING CONGRESS & EXPO2005
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Estimation • Traditional Methods • Geostatistical Methods • Recently Developed Methods Neural Networks Simulation, Fuzzy logic
•
Combination of these Methods
Geostatistics at a glance: Variogram; Kriging; Weighted Average
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Directional Variograms of Accumulation of Al2O3 MD Deposit
Semivariogramme
30 25
-45
20
-75
15
-15
10
15
5
45
0 0
20
40
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60
75
m 80 14
Sources of Error for an Estimation • • • • •
The Important Factors : Loss of information: X ---X X X ? X X ? ? ? ? Geological Incertitude : x y x y yy Insufficient knowledge to interpret the phenomena Discontinuity , interruption, different phenomena A B C D E f w t w e K L v N O P Q R S T 123 • Noise
MMMMMMM
MMMMMMM
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MMMMM MMM
M
M
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ANALYSIS OF THE QUALITY OF DATA • Lack of information • Problem of regularization • Discontinuity, interruption and peculiar phenomena • Insufficient knowledge to interpret the phenomena • Bimodal Population • Different types of criteria 20th WORLD MINING CONGRESS & EXPO2005
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Continental sedimentation Complexity in form and pattern
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Discontinuity
Distance = 6 m Nom Snd S3.01750
Ptoit
Y
407315
Fac 17,5 18 18,5 19 19,5 20 20,5 21 21,5 22 22,5 23 23,5 24 24,5 25 25,5 26 26,5 27 27,5 28 28,5 29 29,5 30 30,5 31 31,5 32 32,5 33
344337
Pf 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82 82
Z
Nom Snd 119 S5.05298
Al2O3
Ptoit
X
Y
407320
Fac 17,5 18 18,5 19 19,5 20 20,5 21 21,5 22 22,5 23 23,5 24 24,5 25 25,5 26 26,5 27 27,5 28 28,5 29 29,5 30 30,5 31 31,5 32 32,5 33
85 85 11 11 11 11 11 11 13 13 13 13 13 13 13 13 13 13 15 15 15 15 13 13 13 13 13 13 13 13 13 13
344340
Z 119
Pf
Al2O3
11,25 11,25 11,25 11,59 11,59 11,59 11,46 11,46 11,78 11,78 11,78 11,78 11,67 11,67 11,67 11,67 11,4 11,4 11,4 11,4 11,18 11,18 11,18 11,18 10,77 10,77 10,77 10,63 10,63 10,63
36,3 36,3 36,3 36,83 36,83 36,83 36,37 36,37 37,53 37,53 37,53 37,53 36,82 36,82 36,82 36,82 36,8 36,8 36,8 36,8 36,61 36,61 36,61 36,61 34,75 34,75 34,75 35,04 35,04 35,04
Minimum 14.5 m of the clay series
0 ??
X
Discontinuity of the properties : Brutal changes of properties cause some problems for mathematical estimation methods, because they tend to smooth the results
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Bimodal Population of K2O 200 160
160
134
120 89
80
146
113 115 81
54
90 68 66 63
82
76
39
40
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K2O Grade in % 20th WORLD MINING CONGRESS & EXPO2005
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1, 6
1, 5
1, 4
1, 3
1, 2
1, 1
1
0, 9
0, 8
0, 7
0, 6
0, 5
0, 4
0, 3
0, 2
0
0, 1
Number of Regularized samples
[< 0,6] et [> 0,6]; Chez MD
Natural Phenoma are Frameworks of Estimation • The geological situation is complex: The differents geological processes can produce a mix of statistical populations in space and time. • Loss of information can hide the logical relationship between data, thus the actual relation will be interpreted as a random or hasardous relation. • Obviously, the scale of observation (sampling grid) must be adapted to the scale of the essential phenomena. • After the sedimentation process disturbs the original relation between data. 20th WORLD MINING CONGRESS & EXPO2005
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The envisaged solutions • Working in the new space of geometry • Taking into account the genesis of the history of the deposits • Investigate the relation between variables
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γ(h) 20
200
15
150
10 5
Comparison of the calculated variograms in a Cartesian system (Plan 50 m) in the NE part of BR deposit for Al2O3 (top), and on the projected values of the surface of sedimentation on a plane. (parameters of variograms, direction: 60° and tolerance: 15°)
Semi Var
100
Pair
50
0
Pair
In the Cartesian system
0 30
60
90
120
150
180
210
240
h(m)
γ(h) 30
On the surface of sedimentation
25
250 200
20
150
15 100
10 Semi Var Pair
5 0 30
60
50 0
90 120 150 180 210 240 h(m)
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Pair
Non Cartesian system
Genetic difference 50
SW
40 30
NE
20 10
60
58
56
More
Al203(%)
54
52
50
48
46
44
0
42
Relative frequency(%)
60
Relative frequency of Al2O3 grade in hard kaolin of the second series in the north eastern part of BR deposit and the south western part of the deposit which contains a canalized type sediment 20th WORLD MINING CONGRESS & EXPO2005
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Statistical comparison Deposit parameter LOI Al2O3 TiO2 Fe2O3 Na2O K2O CaO MgO SiO2 P2O5
BR Ave 13.6 42.5 1.37 1.38 0.07 0.70 0.15 0.12 53.2 0.06
St Dev 1.8 4.3 0.40 0.87 0.04 0.47 0.06 0.07 3.8 0.03
MD Ave St Dev 12.4 1.5 38.8 4.0 1.45 0.45 1.47 0.78 0.06 0.03 0.81 0.40 0.17 0.04 0.14 0.07 56.8 3.7 0.04 0.03
SG Ave 11.4 36.5 1.50 1.47 0.06 1.17 0.07 0.19 58.6 0.06
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BC St Dev 0.9 2.5 0.14 0.25 0.03 0.28 0.03 0.04 2.4 0.02
Ave 11.9 37.6 1.77 1.48 0.07 0.73 0.07 0.14 57.5 0.06
St Dev 0.8 2.7 0.46 0.60 0.03 0.31 0.04 0.04 3.6 0.02
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Sum of frequency in each class is 100 60 50 40 30 20 10
Sandy Clay
Semi grassy with grains
Semi grassy
Grassy with grain
>= 50
48-50
46-48
44-46
42-44
40-42
38-40
36-38
34-36
32-34
30-32
28-30
>28
0
Grassy
Hard Kaolin
Sum of frequency in each class is 100
30
20
10
Grassy with grain
Grassy
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>= 50
48-50
46-48
44-46
20th WORLD MINING CONGRESS &Semi EXPO2005 Sandy Clay grassy with grains Semi grassy
42-44
40-42
38-40
36-38
34-36
32-34
30-32
28-30
>28
0
Hard Kaolin
Principal Component Analysis (PCA) Deposit of SG & BC
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Principal Component Analysis (PCA) Deposit of BR & MD
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DISCUSSION AND CONCLUSION •The complexity of the geological setting due to the presence of different geological processes which can produce a mixture of statistical populations in space and in the time scales is one of the main difficulties of the utilization of geostatistical estimation tools. •The lack of information can hide the logical relationship between data, and then the actual relationship will be interpreted as a random or hazardous relation. The scale of observation (sampling grid) must be adapted to the scale of the essential phenomena and the precision on grades specified by the customers.
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DISCUSSION AND CONCLUSION
• Post-sedimentation processes have disturbed the general sedimentary relation between data, so the geological phenomena related to this processes must be taken into account for estimation. They can be used as a guide to divide the deposits into the more geologically homogeneous sub-domains. • Sedimentary forms are very important for the calculation of the variograms and as a guide to link data during kriging. 20th WORLD MINING CONGRESS & EXPO2005
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Thank you for your attention
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END
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