1. International Atomic Energy Agency Technical Meeting on
Origin of Sandstone Uranium Deposits: A Global Perspective
SANDSTONE-HOSTED URANIUM DEPOSITS AND
PERSPECTIVES ON ISL IN ARGENTINA.
OUTCOMES OF THE IAEA TECHNICAL COOPERATION
PROJECT ARG 03/012-014.
Luis López National Atomic
lopez @cnea.gov.ar Energy Commission
Vienna, 29 May – 1 June 2012
1
2. OUTLINE
• INTRODUCTION
• SANDSTONE-HOSTED URANIUM DEPOSITS
• BASAL CHANNEL
• ROLL FRONT
• TABULAR
• ISL URANIUM PERSPECTIVES – IAEA TC
• PROSPECTING
• EXPLORATION
• FEASIBILITY / RESEACH & DEVELOPMENT
• FINAL CONSIDERATIONS
2
3. INTRODUCTION
The uranium mining
activities in Argentina
began in the 1950s.
The systematic
exploration led to the
discovery of several
uranium deposits.
Airborne radiometric surveys
(1950 – 1970) 3
5. INTRODUCTION
In 1992, Argentina began to import uranium due to
economic reasons, situation that progressively led
to the closing of national production in 1997.
350 -
300 -
USD constant 2009
250 -
USD / kg U
200 -
150 -
Closing of U
100 - production in
Argentina
50 -
0 -
-
-
-
-
-
-
-
-
-
-
-
l l
1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2010 2012 5
6. INTRODUCTION
Currently, the CNEA, Provincial (Chubut, La Rioja,
Santa Cruz), Senior Producers and Junior Companies
are carrying out several uranium projects that have
different degrees of development.
6
7. URANIUM RESOURCES IN ARGENTINA (CNEA)
Cost Category: USD 260 / kg U
REASONABLY
INFERRED
IDENTIFIED RESOURCES ASSURED
RESOURCES
RESOURCES
8,600 t U 11,000 t U
Total 19,600 t U
Source: NEA – IAEA Red Book, 2011 (in press)
7
8. ARGENTINE NPPs
a
ATUCHA I
357 Mwe
b Slightly Enriched U
N
a
c b
EMBALSE
648 Mwe
Natural U
c
ATUCHA II
(start up 2012 - 2013)
745 Mwe
0 1000 km Natural U
8
9. U DEMAND IN ARGENTINA
OPERATION REMAINING DEMAND
NPP START OPERATION
Atucha I 1974 2012 – 2027 800 t U
Embalse 1984 2012 – 2033 1,400 t U
Atucha II 2012 – 2013 40 years 3,700 t U
(start up 2012 - 2013)
CAREM --- 40 years 600 t U
Total 6,500 t U
Current Consumption: 120 t U per year
9
13. SANDSTONE-HOSTED URANIUM DEPOSITS
IN ARGENTINA
Basal channel:
Cerro Solo (Chubut province)
Los Adobes (Chubut province)
Cerro Condor (Chubut province)
Roll front:
Los Colorados (La Rioja province)
Arroyo Perdido (Chubut province)
Tabular:
Sierra Pintada (Mendoza province)
Don Otto (Salta province)
Acosta (Salta province)
Los Chuhuidos (Neuquen province)
Tectonic/ Lithologic
Mafic dykes/ sills in Proterozoic sandstones
13
14.
200 km 24º S
CERRO SOLO U DEPOSIT
San Jorge Basin
(Cretaceous)
32º S Type: Sandstone-hosted
Subtype: Basal channel (U,Mo, Re)
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
48º S
Igneous and Metamorphic Rocks
Mesozoic-Cenozoic
Quaternary volcanics. intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Benítez et al, 1993; Bianchi & Páez, 2005 14
15. CERRO SOLO U DEPOSIT
Schematic Geology:
Chubut Group - Cerro
Barcino Formation (K) :
tuffs.
U U
U
U
Chubut Group - Los
Adobes Formation (K):
fluvial sediments. U
Fm Cañadón Puelman (J) :
andesites.
Source: Benítez, 1997
15
17. CERRO SOLO U DEPOSIT
Identified Resources (< USD 260 / kg U): 9,200 t U.
Average Grade: 0.20 % U.
17
18.
200 km 24º S
LOS ADOBES U DEPOSIT
&
32º S
CERRO CONDOR U DEPOSIT
San Jorge Basin
40º S (Cretaceous)
Type: Sandstone-hosted
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary
Cretaceous
Triassic
Mesozoic
Paleozoic
Precambrian
Paleozoic Subtype: Basal channel
48º S
Igneous and Metamorphic Rocks
Mesozoic-Cenozoic
Quaternary volcanics. intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
Source: Fuente & Gayone, 1999
78º
56º S
18
19. LOS ADOBES U DEPOSIT
Total Production: 120 t U @ 0.12 %.
System: heap leaching + dilute sulphuric acid solution + IX resins.
19
20. CERRO CONDOR U DEPOSIT
Total Production: 56 t U @ 0.08 %.
System: heap leaching + dilute sulphuric acid solution + IX resins.
20
21.
200 km 24º S
LOS COLORADOS U DEPOSIT
Paganzo Basin
(Carboniferous)
32º S
Type: Sandstone-hosted
Subtype: Roll front
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Mesozoic-Cenozoic
Quaternary volcanics.
Cretaceous-Tertiary
48º Sintrusives
Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Belluco et al, 1999; Caudillo Resources, 2012 21
22. LOS COLORADOS U DEPOSIT
Total Production: 55 t U @ 0.064 %.
System: heap leaching + dilute sulphuric acid solution + IX resins.
22
23.
200 km 24º S
ARROYO PERDIDO U DEPOSIT
San Jorge Basin
(Cretaceous)
32º S
Type: Sandstone-hosted
Subtype: Roll front ?
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
48º S
Igneous and Metamorphic Rocks
Mesozoic-Cenozoic
Quaternary volcanics. intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Benítez & Marveggio, 2005; López, 2010 23
24. ARROYO PERDIDO U DEPOSIT
SW NE
m Gamma
Gamma Gamma
25 SP R SP R SP R
T
u
f
f
75
F
l
125 U
u
v
i
U a
U
l
U U
175
C
y
0 200 m U U c
l
e 24
25.
200 km 24º S
SIERRA PINTADA U DEPOSIT
San Rafael Basin
(Lower Permian)
32º S
Type: Sandstone-hosted
Subtype:Tabular (Strata-bound volc.)
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Mesozoic-Cenozoic
Quaternary volcanics.
Cretaceous-Tertiary
48º Sintrusives
Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
25
Source: Salvarredi, 1999; Navarra, 2001-6; Kleiman, 2012
26. SIERRA PINTADA U DEPOSIT
Total Production: 1,800 t U @ 0.09 – 0.29 % U.
System: heap leaching + dilute sulphuric acid solution +
ion exchange resins.
Identified Resources (< USD 130 / kg U): 10,100 t U.
Average grade: 0.10 % U.
Source: NEA-IAEA Red Book, 2011 (in press) 26
27.
200 km 24º S
DON OTTO U DEPOSIT
Salta Basin
(Cretaceous - Tertiary)
32º S
Type: Sandstone-hosted
Subtype: Tabular (U, V)
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Gorustovich, 2010; López et al 2010 27
28. Don Otto
25º20'
25º20'
M.M. de
M.M. M.
de
Güemesde
M.
Güemes
GÜEMES
DON OTTO
Depósito de uranio U
El Leñadero
DEPOSIT
Localidad
25º40'
Los Berthos El Desecho
Los Berthos
LOS BERTHOS
Fallas
Emmy 00 55 10 Km
10 Km
Sinclinal
N
Bosquejo geológico del Distrito Tonco Amblayo
Bosquejo geológico del Distrito Tonco Amblayo
Depósitos modernos Cover
Quaternary
Depósitos modernos
Grupo Payogastilla
Tertiary Sediments
Grupo Payogastilla
25º30' Subgrupo Santa Bárbara
25º30' Subgrupo Santa Bárbara
Cretaceous
AMBLAYO Subgrupo Balbuena
Tertiary
AMBLAYO
AMBLAYO Subgrupo Balbuena
Basin
Subgrupo Pirgua
Pedro NICOLÁS
P. Subgrupo Pirgua
Nicolás
Pedro
Nicolás
Precambrian
Formación Puncoviscana Basement
Don Otto Formación Puncoviscana
DONOtto
Don OTTO U Deposit
Depósito de uranio
Depósito de uranio
El Leñadero Town
Localidad
25º40' EL Leñadero
El LEÑADERO
El Desecho Localidad
Fallas
Fault
25º40' ELDesecho
El DESECHOEmmy Fallas 0 5 10 Km
Sinclinal
Syncline
Emmy
EMMY
0 5 10 Km
Sinclinal 28
29. DON OTTO U DEPOSIT
Total Production: 202 t U @ 0.1 %.
System: heap leaching + dilute sulphuric acid solution +
ion exchange resins.
29
30.
200 km 24º S
ACOSTA SITE U DEPOSITS
Salta Basin
(Cretaceous - Tertiary)
32º S
Type: Sandstone-hosted
Subtype: Tabular (U, Cu, Zn)
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Ferreira et al, 2012 30
31. ACOSTA SITE U DEPOSITS
Strata-bound U mineralization
hosted by grey micaceous pelites
is associated with high contents
of Cu and Zn.
31
32.
200 km 24º S
LOS CHIHUIDOS U DEPOSITS
Neuquen Basin
(Cretaceous)
32º S
Type: Sandstone-hosted
Subtype: Tabular (U, V, Cu)
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
Source: Rojas, 1999 32
33. LOS CHIHUIDOS U DEPOSITS
Features of U occurrences:
Thickness= 0.10 – 0.20 meters
U= 0.21 %
V= 0.95 – 1.20 %
Cu= 1.00 – 1.90 %
33
34. OUTLINE
• INTRODUCTION
• SANDSTONE-HOSTED URANIUM DEPOSITS
• BASAL CHANNEL
• ROLL FRONT
• TABULAR
ISL URANIUM PERSPECTIVES – IAEA TC
• PROSPECTING
• EXPLORATION
• FEASIBILITY / RESEACH & DEVELOPMENT
• FINAL CONSIDERATIONS
34
35. TC PROJECT ON ISL
"Geology favorability, production feasibility and
environmental impact assessment of uranium
deposits exploitable by the in situ leaching
technology (ISL)"
(ARG 3/012 – 14)
Associated with the IAEA Regional TC Project “Upgrading of
Uranium Exploration, Exploitation and Yellowcake Production
Techniques taking Environmental Problems into Account”
35
36. LOGICAL FRAMEWORK
G
O
The country sustainably produces the uranium to
A cover local demand for the nuclear power plants
L
P
U
R
High uranium potential areas studied,
P within the mining cycle of In Situ Leaching technology
O
S
E
O Geology
U Environmental
favourability Production
T impact Qualified Operative
P and uranium feasibility
assessment staff equipments
U exploration performed
T performed
S
performed
I Project managing, applied geological investigation, getting exploration permits,
N
P drilling and logging, pilot tests, hydrogeological studies, cost analysis,
U environmental and aquifer vulnerability studies, fellowships, scientific visits,
T
S expert missions, purchasing and setting up equipments
36
38. U PROJECTS ON ISL
STAGE INVESTMENT- PROFIT PROJECTS
0 U Prospecting
Generative 1
(Neuquina Basin) D
5 E
Exploration V
Discovery Y U Exploration
2 (San Jorge Basin)
E
Evaluation 10 e L
a O
r P
Pre Feasibility s
15 M
Feasibility / R&D E
Feasibility 3 (Don Otto Deposit) N
20 T
Production
30
38
39. 1
ISL PROSPECTING PROJECT
200 km 24º S
Neuquina Basin
(Cretaceous - Tertiary)
32º S
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
39
40. 1
ISL PROSPECTING PROJECT
The compilation of previous information, field
reconnaissance, the gathering of logging and sampling
data from oil wells, chemical analyses and results
interpretation are some of the tasks being performed.
40
41. 1
U PROSPECTING AREAS
N
oil drilled hole
5 km
41
42. 2
ISL EXPLORATION PROJECT
200 km 24º S
San Jorge Basin
(Cretaceous)
32º S
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
42
43. 2
U ANOMALIES
Based on
airborne
radiometric
surveys and the
field geological
reconnaissance, s
ome exploration
targets with ISL
possibilities were
defined.
43
44. 2
SCHEMATIC CROSS - SECTION
W Cerro Solo U deposit ISL area of interest E
CO2 emission
water flow
Tuffs
Fluvial sediments
2 km
U
Andesites
Granites
44
46. 2 DRILLING SURVEY
N
drilled hole
mineralised level
The drilling survey
performed has 0 500 m
given encouraging
results:
- 3 U mineralized
levels.
- Hypothesis of roll
front deposit type.
46
47. 2 LOGS CROSS - SECTION
SW NE
m Gamma
Gamma Gamma
25 SP R SP R SP R
T
u
f
f
75
F
l
125 U
u
v
i
U a
U
l
U U
175
C
y
0 200 m U U c
l
e 47
48. 3 ISL FEASIBILITY / R & D PROJECT
200 km 24º S
Don Otto U Deposit
(Cretaceous)
32º S
40º S
Sedimentary Rocks
Quaternary Jurassic Devonian
Tertiary Triassic Paleozoic
Precambrian
Cretaceous Mesozoic Paleozoic
Igneous and Metamorphic Rocks
Quaternary volcanics. 48º S
Mesozoic-Cenozoic
intrusives
Cretaceous-Tertiary Paleozoic-Mesozoic
volcanics intrusives
Mesozoic volcanics Precambrian
undifferentiated
Paleozoic volcanics
54º W
66º W
W
78º
56º S
48
49. 3
DON OTTO U
DEPOSIT
- Type: Sandstone Hosted.
- Subtype: Tabular U-V.
49
50. 3
PROJECT PURPOSE
The main purpose is to address studies and pilot
tests to determine the block leaching feasibility to
recover the uranium from the remaining resources
of the deposit.
This project is not based on the uranium
production itself but on developing a technology
that could help for the uranium exploitation of
similar deposits located in the district.
50
51. 3 U RESOURCES
SECTOR LA YESERA SECTOR TAPÓN NORTE SECTOR TAPÓN SUR 1
CH.43 Nivel +50 Nivel +50
CH.40
Quebrada del Tapón
CH.34
CH.45
CH.36
CH.33
Nivel "0" Nivel "0"
CH.26
CH.22
CH.25
CH.27
Nivel -40
Nivel -40
TN-60 I
CH.47
CH.46
Chiflón
TN-80 II
CH.26
CH.25
CH.30
CH.28
CH.19
CH.22
CH.21
CH.20
CH.23
TN-80 III pa
Ram
Nivel -80
Nivel -80
TN-120 III
CH.37
CH.36
TN-120 X TN-120 IX TN-120 VIII TN-120 VII TN-120 VI TN-120 V TN-120 IV TN-120 II
CH.38
CH.39
TN-140 III TN-140 II Nivel -120
TN-140 VII
TN-160 X TN-160 IX TN-160 VIII
TN-180 VII TN-180 VI TN-180 V TN-180 IV TN-180 III TN-180 II
SECTOR CENTRAL SECTOR SUR
1 SECTOR NORTE
Nivel +50
Nivel +50
0-XVI
Nivel "0"
Cortaveta C Cortaveta B Cortaveta A O- III a O- IV a Nivel "0"
CH.17
CS-40-1
Nivel -40
Nivel -40
CH.16
CS-80-1
CH.5
CH.7
CH.2
Nivel -80 Nivel -80
CS-90-1
Ram CS-100 VII CS-100 V CS-110 IV CS-110 III CS-100 II
YACIMIENTO DON OTTO
CH.15
pa
CH.14
CH.10
CH.13
CH.12
CH.11
DPTO. SAN CARLOS - SALTA
Nivel -120
Nivel -120 CORTE VERTICAL DE LABOREOS
ESTIMACION DE RESERVAS
Al 31-08-81 t.c.f. 0,05% U O
3 8
RAR PR Paño c/explotación Recursos
Perspectivas Reservas
IR Mined Out 0 50 100 150m
Perfil Longitudinal del Yacimiento Don Otto.
3º NIVEL MINERALIZADO
Current Identified Resources: 216 t U
51
52. 3 U RESOURCES
TOR LA YESERA SECTOR TAPÓN NORTE
RAR PR
IR Mined Out
Nivel +50
CH.43
CH.40
CH.36
Nivel "0"
Nivel -40
TN-60 I
TN-80 II
TN-80 III
R ampa
Nivel -80
TN-120 III TN-120 II
CH.37
CH.36
TN-120 IX TN-120 VIII TN-120 VII TN-120 VI TN-120 V TN-120 IV
CH.39
CH.38
Nivel -120
TN-140 III TN-140 II
TN-140 VII
TN-160 IX TN-160 VIII
TN-180 VII TN-180 VI TN-180 V TN-180 IV TN-180 III TN-180 II
52 SE
1 SECTOR NORTE
54. 3
STUDIES ON PELITES
633 Counts / Min
Studies by J-L Lescuyer and R. Sol (AREVA) 54
55. 3 STUDIES ON PELITES
Natural U mineral Natural
Ligth Light U mineral
U mineral Ultraviolet
Ultraviolet
Ligth Ligth U mineral
55
56. 3
STUDIES ON SANDSTONES
3124 Counts / Min
Studies by J-L Lescuyer and R. Sol (AREVA) 56
57. 3 STUDIES ON SANDSTONES
Natural Natural
Light Light U mineral
U mineral
Ultraviolet Ultraviolet
Ligth Ligth U mineral
U mineral
57
58. 3
REMAKS ON DETERMINATIONS
- The weak compaction of the sediments allowed the
circulation of fluids enriched in Uranyl (UO2)+2 ions.
- The sedimentary environment allowed the
precipitation of yellow products both in the
preserved porosity (sandstones) and microporosity
(pelites).
Studies by J-L Lescuyer and R. Sol (AREVA) 58
59. 3 DRILLING PROGRAM
North
Mineralized Area
Planned Borehole
Executed Borehole
1 Km
59
64. OUTLINE
• INTRODUCTION
• SANDSTONE-HOSTED URANIUM DEPOSITS
• BASAL CHANNEL
• ROLL FRONT
• TABULAR
• ISL URANIUM PERSPECTIVES – IAEA TC
• PROSPECTING
• EXPLORATION
• FEASIBILITY / RESEACH & DEVELOPMENT
FINAL CONSIDERATIONS
64
65. ARGENTINE URANIUM DEPOSITS
Uranium Resources – t U
< 500 500 – 1.000 1,000-10,000 10,000 – 100,000 > 100,000 Total
G < 0,03 3 9 65 32 6 115
r
a 0.03 – 0.10 13 26 96 31 6 172
d
0.10 – 1.00 33 106 282 89 7 517
e
s 1.00 – 5.00 5 3 13 10 0 31
% > 5.00 0 0 1 0 2 3
U
Grand Total 54 144 457 162 21 838
Source: IAEA, 2009 65
66. URANIUM RESOURCES BY DEPOSITS
CNEA, ARGENTINA
Cost Category: USD 260 / kg U
RESOURCES IDENTIFIED UNDISCOVERED
CERRO SOLO 9,200 t U ---
SIERRA PINTADA 10,200 t U ---
OTHER 200 t U 11,600 t U
19,600 t U0 11,600 t U
Source: NEA – IAEA Red Book, 2011 (in press)
66
67. URANIUM PRODUCTION IN ARGENTINA 1952 - 1997
Granite
10% Other
sandstone
26%
Sierra Pintada
64%
Total: 2,600 t U
Source: NEA-IAEA Red Book, 2011 (in press) 67
68. FINAL CONSIDERATIONS
It can be pointed out
that the existence of
extensive basins with
high uranium potential
and different
mineralization models
configures promising
conditions to develop
new uranium
resources in
Argentina.
68
69. FINAL CONSIDERATIONS
In this context, the
uranium deposits
related to
sandstones, now a
days constitute the
most attractive
exploration targets
in the country.
69
70. FINAL CONSIDERATIONS
ISL technology would
constitute a more
sustainable option for
uranium production.
As an exploration
strategy, new surveys
should be addressed to
Upper Cretaceous -
Tertiary basins,
including
hydrogeological studies.
70
71. FINAL CONSIDERATIONS
The role of the
IAEA Technical
Cooperation is
highly relevant for
improving the
capability of
Argentina to
strategically plan
and efficiently carry
out its uranium
mining projects.
71
72. National Atomic
Energy Commission
THANK YOU!
Luis López
lopez@cnea.gov.ar
72