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Relevant tools for
generating geologic
models at Division Andina
Juan Hermosilla B.
Patricio Cuadra C.
Gonzalo Rojas S.
Cutting relationships between
porphyry and tourmaline breccias,
Ro Blanco area
CODELCOA N D I N A
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Introduction
The Ro Blanco-Los Bronces
copper-molybdenum district is
emplaced in the upper Miocene to
Pliocene porphyry copper belt ofCentral Andes
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Geological Background
Edad Rgimen
Tectnico
Unidades Estratificadas Unidades Intrusivas plutnicas Prfidos y
brechas
Plioceno-Cuaternario
(4-0 Ma)
Relajacin post-
compresin
Morrenas, coluvios y aluvios
no consolidados
Mioceno Superior-
Plioceno Inferior (6-4
Ma)
Compresin Niveles piroclstcos
subareos de la Chimenea
Rioltica
Prfidos dacticos y
andesticos,
brechas de
turmalina y de polvo
de roca, Chimenea
Rioltica
Mioceno Medio a
Superior (14-8 Ma)
Compresin Fm. Farellones, miembro
piroclstico superior
Monzonita, cuarzo-monzonita,
Granodiorita Ro Blanco, tonalita,
diorita, Granodiorita Cascada
Prfidos
andesticos
Mioceno Inferior Alto-
Mioceno Medio
Compresin Fm. Farellones, miembro
lvico intermedio
Sienogranito de Biotita
Mioceno Infer ior Compresin Fm. Farel lones, miembro
piroclstico inferior (fuera del
rea de trabajo)
Granodioritas, dioritas
Eoceno Superior-
Mioceno Inferior
Extensin Fm. Abanico
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The district, is the worlds largest copper
concentration, exceeding 29.000 Mt (at 0.2% cut-off)
Cooke et. al. 2005. Camus, 2002.Eoceno-Oligoceno Belt Mioceno-Plioceno Belt
110 MT Cu
4Mt Mo
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Why Geological Model is important ?
To understand thedistribution of metal content
Provides knowledge about
geological controls to guidethe resources estimation
Development of conceptual
models for the exploration ofnew resources in the district
DDH-4237
DDH-949
DDH-942-A
Modelo Litologa 2006 Modelo Litologa 2008
DDH-4237
DDH-949
DDH-942-A
Modelo Litologa 2006 Modelo Litologa 2008
SondajeDDH4237200m. 2.0%CuT
SondajeDDH949170m. 2.15%CuTy 0.011%Mo
DDH-4237
DDH-949
DDH-942-A
Modelo Litologa 2006 Modelo Litologa 2008
SondajeDDH4237200m. 2.0%CuT
SondajeDDH949170m. 2.15%CuTy 0.011%Mo
DDH-4237
DDH-949
DDH-942-A
Modelo Litologa 2006 Modelo Litologa 2008
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-
- -
-
-
- -
ae 3. . T
a e 9 9
. . T .
-
-
- -
ae 3. . T
a e 9 9
. . T .
-
-
- -
Modelo Litologa 2006
DDH-841
Modelo Litologa 2008
DDH-845
DDH-877
DDH-894
DDH-919
DDH-884
DDH-913
DDH-889
DDH-841
Modelo Litologa 2006
DDH-841
Modelo Litologa 2008
DDH-845
DDH-877
DDH-894
DDH-919
DDH-884
DDH-913
DDH-889
DDH-841
DDH-845
DDH-877
DDH-894
DDH-919
DDH-884
DDH-913
DDH-889
DDH-841
Modelo Litologa 2006 Modelo Litologa 2008
DDH-845
DDH-877
DDH-894
DDH-919
DDH-884
DDH-913
DDH-889
DDH-841
Modelo Litologa 2006 Modelo Litologa 2008
EMSA, 2010
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2004: A major methodological change
in Andina Divisin
Sampling support changed from 10 m to 2 m
Continuous improvement in geological core logging
methodology
different events of intrusion/breccia andalteration/mineralisation of the deposit
Application ofQA/QC procedures throughout the
entire process
Systematic application ofpetrographical studies and
strategically oriented geocronological analysis.
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Why Change the Geological core logging
methodology >>> KNOWLEDGE
State of Art logging methodologies
Geological processes understanding
Porphyry copper geological knowledge
Repeatability and auditability of data
Diverse experience of geologists
Lack of alteration and mineralization concepts
Team turnover
Strengths
Weakn
esses
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Team turnover
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Changes in Geological core logging methodology
PRE 2004 2004
1:500 SCALE1:100 SCALE
INTENSITIES (1-5)
Lithological logging, > 60
rock codes.
Simplification of rock codes
table (27). Detailed breccia and
porphyry recognition.
Generic logging of
alteration and ore
minerals, for each 10 m
intervals.
Oriented to a detailed
understanding of primary
alteration and/or mineralisationcontrols. Single minerals
logging.
Only sulphides relative
ratios.
Total volume, relative ratios
and occurrence of sulphides.
Veinlets not logged.Veinlet logging (El Salvador
scheme.
Total Sericite loggingIdentification of gray-green
sericite (SGV).
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Changes in Geological core logging methodology
2006 CURRENT
1:100 SCALE
VOLUMETRIC (%)
1:200 SCALE
VOLUMETRIC (%)
Emphasis on the detailed
logging oflithological contacts,
breccias and porphyries units.
Oriented to changes in
parameters that control the
alteration and/or mineralisation.
Simplified logging of
porphyries..
Oriented to log the main
alteration/mineralisation events,
through mineral associations.
Logging of Alteration Zones
Alteration associations include
all forms of occurrence of
alteration minerals (selective,
penetrative, patches,
brecciation, halos, etc.).
Differentiates the occurrence
forms according to its impact on
sulphide distribution. Selective
are logged separately of
penetrative texture-destructive
minerals.
Sulphides occurrence logging by
type of ore.
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Innovation in Methodology
>>> Standardization, control and care of geological
information
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Innovative introduction to the
Core Logging System
Considers a period of training in geological core logging,
whose aim is to provide standardization of knowledge and
practices of geological mapping
Guided presentations on:
Regional and District Geology of the deposit
Geological model relevant reports
Methodologies of data Capture and Analysis
Mine Geology Relevant Background
Relevant Background on Geometallurgy
Relevant Background on Resources Estimation
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Geological Core Logging:
Internal working procedures and digital systems
logging
Geological logging procedure of Diamond Drill cores
and Cutting samples
QA/QC applied to Core Logging
Petrocalcographic studies procedures
Representative Lithological Samples
Training on Digital Mapping System
Innovative introduction to the
Core Logging System
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Innovation in Induction to the Core logging
Assignment and Objectives
Designed to establish a direct link between the geologists
dedicated to geological interpretation and data
acquisition team, establishing requirements for each of
the drill holes, according to the objectives of geological
modelling .
Activities :
Review section and plan interpretation
Determine experience and capacities of the geologist
Online check for information of interpreted sections
Comparing information between different geologists of the team
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Innovation in Standardisation of Mapping
Intensive reviews of geologists in training ,according to
the experience degree, with the objective to strengthen
the methodology into the team. Eventually, the
replacement of the log which does not achieve the
required quality must be done.
Activities :
Online review at least during the first three months of work by a
mapping quality team Check of consistency of information
Duplicate mappings
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Innovation in Control Section
Information from detailed core logging must be regularly
transferred to draft sections and/or plans to control the
consistency and reproducibility of the data between nearby
drilling holes.
Activities :
At least, rock types, alteration and ore mineral associations must be considered.
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Nube DispersinLeyes CuTAnalticas/ Estimada
r2 = 0.6532; r= 0.8082,p = 00.0000; y = 0.1486+ 0.7527*x
0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0 5 .5 6 .0
CuTEstimada(%)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
CuT
Analtica(%)
DiferenciaLeyesCuT Analtica/ Estimada
0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5 4 .0 4 .5 5 .0 5 .5 6 .0
CuT Analtica(%)
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
Dif.CuT(%)
Innovation in Statistical Analysis
Statistical analysis of data must be done systematically
allowing categorize the quality of the information
obtained to take prompt actions appropriate techniques
to ensure the success of the process of geological data
capture
Activities :
Comparison between grade visual estimation v/s chemical results in cases
of logs done without chemical analysis
Chequeo Litologa (Quick Log v/s 1:200 logged)
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Special Studies
To support mineralogical concepts and identification
special studies must be done
Activities :
Microscopic detailed studies with emphasis on characterization of
alteration mineral associations, assemblages of sulphide, a detaileddescription of filling and haloes veinlets
XRD in clay minerals
Infrared Spectroscopy (PIMA) in hand samples
XRF,ICP-MS, lithogeochemical analysis
QemScan in sulphide and alteration mineral associations
Microprobe in sericite phyllosilicates
Fluid Inclusin in veins
Geochronological Anaysis
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>>> Standardization, Control and Care of
geological information
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>>> GEOLOGICAL MODELLING
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GEOLOGICAL MODELLING / GENETIC KNOWLEDGEParagenesis Lithologic, Veins and Mineralization Events
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>>> GEOLOGICAL MODELLING CPY-(BO-SSCU); TS>1.0%
DISTRIBUCION DE SULFUROS
PY>>CPY; TS>2.0%
PY>>CPY; TS>1.0%
PY>>CPY; TSCPY; TS>2.0%
CPY>PY; TSPY; TS>2.0%
CPY>>PY; TS>2.0%
CPY>BO; TS>1.5%
CPY>PY; TSBO; TS