Mineral Potential Assessment Techniques and Methods Explained

 
M
e
t
h
o
d
s
 
o
f
 
M
i
n
e
r
a
l
 
P
o
t
e
n
t
i
a
l
 
A
s
s
e
s
s
m
e
n
t
:
A
 
M
i
n
e
r
a
l
 
S
y
s
t
e
m
s
 
A
p
p
r
o
a
c
h
 
 
O
u
t
l
i
n
e
 
Mineral potential assessment
Methods of assessment (mineral potential,
prospectivity, and favourability maps)
Mineral-systems approach
definition, advantages and disadvantages
Lessons learnt and not learnt
 
 
URAM 2014
 
Mineral potential assessment
 
M
i
n
e
r
a
l
 
p
o
t
e
n
t
i
a
l
Likelihood
 that an economic mineral deposits could have
formed in the area
Probabilistic approach to mineral deposits instead of
deterministic
Probabilities are conditional
on geological processes occurring in an area
on geological features indicative of those processes
Probability of sandstone-hosted uranium deposits in an area
process: transport of U
geological features:  leachable source of U; permeable
sandstone; hydrogeological gradient
 
 
URAM 2014
Delineate areas
permissive for a
deposit
Estimate number of
deposits
Estimate tonnage of
metals at different
probabilities
Methods: NURE; 3-
part USGS; Deposit
density etc
 
Methods of assessment (Quantitative)
 
URAM 2014
Delineate areas permissive
for a deposit
Estimate and assign
probabilities
Non-numerical (high,
moderate, low)
Ordinal (numbers
expressing ranking)
Cardinal (numbers
expressing quantities);
can be computed by
probability equations
 
 
Methods of assessment (Qualitative)
 
Mineral potential assessment
 
 
GIS methods of assessment
 
Methods are not quantitative but the method of visualisation
is quantitative
Produce favourability or prospectivity maps by estimating
probabilities
Dominantly data-driven and ‘objective’
Techniques (see Bonham-Carter, 1994):
Boolean logic
Index overlay
Bayesian (Weights of evidence)
Fuzzy logic
 
Mineral potential assessment
 
Which method and why
 
Depends on the purpose/aim/objective
For regional-scale exploration targeting
qualitative (GIS-based)
For local-scale brown-fields exploration
qualitative (GIS-based)
Competing land-use decisions
quantitative
qualitative
For mineral endowment and inventory
quantitative
 
 
Prospectivity
map
Favourability
map
Mineral
potential
map
 
Essential for qualitative and quantitative methods
Delineation of permissive or
favourable areas
 
URAM 2014
Mineral deposit models/types
Features essential for a fertile
mineralising process
Mineral-systems
 
Using
 
Identified in
 
Or
 
Wyborn et al (1994)
Australian Proterozoic mineral system: essential
ingredients and mappable criteria
“All geological factors that control generation and
preservation of mineral deposits …”
Stress on “Processes”
Analogous to Petroleum Systems
Emergence of Relational Databases and GISs
 
M
i
n
e
r
a
l
 
s
y
s
t
e
m
:
 
i
n
i
t
i
a
l
 
c
o
n
c
e
p
t
 
URAM 2014
 
Seven important geological factors
 
1.
Source of fluids and ligands
2.
Source of metals and other components
3.
Migration pathways (inflow and outflow zones)
4.
Thermal gradients
5.
Source of energy to transport fluid and metals
6.
Mechanical and structural focusing mechanism at the
trap site
7.
Chemical and/or physical cause for precipitation at the
trap site
 
URAM 2014
 
Mineral system
 (
Knox-Robinson & Wyborn, 1997
)
 
URAM 2014
source-pathway-trap paradigm
 
Mineral potential assessment method
Setting
 
Source
Metal
Ligand
Energy
Trap:
Mechanical
Chemical
 
Preservation
 
Timing
Features
Of
Mineral System
Identify
mappable
geological
features
 
Assign
probabilities to
mappable features
Map:
prospectivity,
favourability,
mineral potential
 
Pathway
 
Assess
mineral
potential
(by computing
 probabilities)
Mineral System
Probabilistic
 
+
 
combining 2   approaches
 
URAM 2014
 
Assessments at various scales
 
http://www.ga.gov.au/minerals/projects/conclude
d-projects/mineral-potential.html
 
http://www.ga.gov.au/minerals/projects/conclude
d-projects/uranium-systems.html
 
Limitations of mineral-systems approach
 
Preservation considered important but listed factors
do not include features critical for preservation
Age, duration and relative timing of events in a
mineral system do not receive adequate attention
Requires change to focus on ‘giant’ instead of
average-size deposits
Requires rethinking to take in take into account
clustering of deposits
 
URAM 2014
 
URAM 2014
 
4 regions with unconformity-related uranium
Alligator Rivers and Eastern Athabasca
similar
Rum Jungle and
S Alligator Valley
different
Supergiant (Bull Elephant): Olympic Dam
O
l
y
m
p
i
c
 
D
a
m
 
i
s
 
l
a
r
g
e
r
t
h
a
n
 
P
r
o
m
i
n
e
n
t
 
H
i
l
l
:
~
2
0
0
 
t
i
m
e
s
 
f
o
r
 
U
~
4
5
 
t
i
m
e
s
 
f
o
r
 
C
u
~
2
0
 
t
i
m
e
s
 
f
o
r
 
A
u
O
l
y
m
p
i
c
 
D
a
m
(
2
.
2
4
 
M
t
 
U
3
O
8
;
6
8
 
M
t
 
C
u
;
 
2
4
8
0
 
t
 
A
u
)
P
r
o
m
i
n
e
n
t
 
H
i
l
l
 
(
0
.
0
1
 
M
t
 
U
3
O
8
;
1
.
5
 
M
t
 
C
u
;
 
1
1
5
 
t
 
A
u
)
URAM 2014
 
Mineral potential assessment
 
Reliability or robustness of assessment
 
Depends on
Knowledge of mineral systems/deposit styles (
their critical
features
)
Identification of mappable signatures in datasets which
correspond to critical features of mineral systems
Extent and quality of datasets
 
URAM 2014
 
Conclusions
 
Choice of methods depends on the objective
Basics:
Know your mineral system (deposit-type): SCIENCE
Create useful datasets: A MUST
Mineral system approach can be rewarding. For
successful examples visit GA’s website:
http://www.ga.gov.au/minerals/projects/concluded-projects/mineral-potential.html
; and
http://www.ga.gov.au/minerals/projects/concluded-projects/uranium-systems.html
Don’t overdo or oversell it (only detailed exploration such
as drilling can find a deposit)
Slide Note
Embed
Share

Comprehensive overview of mineral potential assessment methods using a mineral systems approach. Explore qualitative and quantitative approaches, GIS methods, and the assessment of mineral likelihood and prospects. Understand the advantages, disadvantages, and applications of different techniques for regional and local-scale exploration.


Uploaded on Aug 25, 2024 | 1 Views


Download Presentation

Please find below an Image/Link to download the presentation.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. Download presentation by click this link. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.

E N D

Presentation Transcript


  1. Methods of Mineral Potential Assessment: A Mineral Systems Approach Ranger

  2. Outline Mineral potential assessment Methods of assessment (mineral potential, prospectivity, and favourability maps) Mineral-systems approach definition, advantages and disadvantages Lessons learnt and not learnt URAM 2014

  3. Mineral potential Likelihood that an economic mineral deposits could have formed in the area Probabilistic approach to mineral deposits instead of deterministic Probabilities are conditional on geological processes occurring in an area on geological features indicative of those processes Probability of sandstone-hosted uranium deposits in an area process: transport of U geological features: leachable source of U; permeable sandstone; hydrogeological gradient Mineral potential assessment

  4. Methods of assessment (Quantitative) Delineate areas permissive for a deposit Estimate number of deposits Estimate tonnage of metals at different probabilities Methods: NURE; 3- part USGS; Deposit density etc probability 90% 50% 10% Uranium (t) xx yy zz URAM 2014

  5. Methods of assessment (Qualitative) Delineate areas permissive for a deposit Estimate and assign probabilities Non-numerical (high, moderate, low) Ordinal (numbers expressing ranking) Cardinal (numbers expressing quantities); can be computed by probability equations URAM 2014

  6. GIS methods of assessment Methods are not quantitative but the method of visualisation is quantitative Produce favourability or prospectivity maps by estimating probabilities Dominantly data-driven and objective Techniques (see Bonham-Carter, 1994): Boolean logic Index overlay Bayesian (Weights of evidence) Fuzzy logic Mineral potential assessment

  7. Which method and why Depends on the purpose/aim/objective Prospectivity map Favourability map For regional-scale exploration targeting qualitative (GIS-based) For local-scale brown-fields exploration qualitative (GIS-based) Competing land-use decisions quantitative qualitative Mineral potential map For mineral endowment and inventory quantitative Mineral potential assessment

  8. Essential for qualitative and quantitative methods Delineation of permissive or favourable areas Using Features essential for a fertile mineralising process Identified in Mineral deposit models/types Or Mineral-systems URAM 2014

  9. Mineral system: initial concept Wyborn et al (1994) Australian Proterozoic mineral system: essential ingredients and mappable criteria All geological factors that control generation and preservation of mineral deposits Stress on Processes Analogous to Petroleum Systems Emergence of Relational Databases and GISs URAM 2014

  10. Seven important geological factors 1. Source of fluids and ligands 2. Source of metals and other components 3. Migration pathways (inflow and outflow zones) 4. Thermal gradients 5. Source of energy to transport fluid and metals 6. Mechanical and structural focusing mechanism at the trap site 7. Chemical and/or physical cause for precipitation at the trap site URAM 2014

  11. Mineral system (Knox-Robinson & Wyborn, 1997) source-pathway-trap paradigm URAM 2014

  12. Mineral potential assessment method Features Of Mineral System Mineral System combining 2 approaches Probabilistic + Setting Source Metal Ligand Energy Assess mineral potential (by computing probabilities) Identify mappable geological features Assign Pathway probabilities to mappable features Trap: Mechanical Chemical Timing Map: prospectivity, favourability, mineral potential Preservation

  13. Assessments at various scales http://www.ga.gov.au/minerals/projects/conclude d-projects/mineral-potential.html http://www.ga.gov.au/minerals/projects/conclude d-projects/uranium-systems.html URAM 2014

  14. Limitations of mineral-systems approach Preservation considered important but listed factors do not include features critical for preservation Age, duration and relative timing of events in a mineral system do not receive adequate attention Requires change to focus on giant instead of average-size deposits Requires rethinking to take in take into account clustering of deposits URAM 2014

  15. 4 regions with unconformity-related uranium Rum Jungle and S Alligator Valley different Alligator Rivers and Eastern Athabasca similar URAM 2014

  16. Supergiant (Bull Elephant): Olympic Dam Prominent Hill (0.01 Mt U3O8; 1.5 Mt Cu; 115 t Au) Olympic Dam (2.24 Mt U3O8; 68 Mt Cu; 2480 t Au) Olympic Dam is larger than Prominent Hill: ~200 times for U ~45 times for Cu ~20 times for Au 0 25 50 100 Kilometers URAM 2014

  17. Reliability or robustness of assessment Depends on Knowledge of mineral systems/deposit styles (their critical features) Identification of mappable signatures in datasets which correspond to critical features of mineral systems Extent and quality of datasets Mineral potential assessment

  18. Conclusions Choice of methods depends on the objective Basics: Know your mineral system (deposit-type): SCIENCE Create useful datasets: A MUST Mineral system approach can be rewarding. For successful examples visit GA s website: http://www.ga.gov.au/minerals/projects/concluded-projects/mineral-potential.html; and http://www.ga.gov.au/minerals/projects/concluded-projects/uranium-systems.html Don t overdo or oversell it (only detailed exploration such as drilling can find a deposit) URAM 2014

Related


More Related Content

giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#