Recovery of Uranium From Carbonaceous Ores€¦ · · 2014-11-07Recovery of Uranium From Carbonaceous Ores 1 By : Grenvil Dunn Nelson Mora ... Process Role(s) ... •Variable weathering

Orway Mineral Consultants (WA) Pty Ltd

Recovery of Uranium From Carbonaceous Ores

1

By : Grenvil Dunn Nelson Mora Yong Teo


Overview

African Project

Australian Project

2


INTRODUCTION

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Various Examples of Organic Matter

Coal type (eg Peat, lignite, anthracite)

Coal Constituents /macerals

Fulvic, humic acid

Woody material herbacious matter

Carbonaceous materials

Tar

Bituminous materials

4


Roles of Organic Matter in Uranium Deposits

5

Process Role(s) of Organic Matter

Mobilisation Decomposition of organic material raises CO2 which

forms acid to leach uranium

Transportation Uranium cation held by ion exchange to fulvic or

humic acid can be transported with organic matter

Concentration Organic materials with functional group such as humic

acid can bind uranium and other metals by ion

exchange or chelation

Reduction Organic matter may reduce uranium directly or

through the reduction (biogenic or chemical) of sulfate

to sulfide and subsequently reduces uranium.

Preservation Reduced uranium intimately mixed with organic matter

are protected from oxidation particularly if the organic

matter becomes refractory through burial

Leventhal, J.S., Roles of Organic Matter in Ore Deposits


Uranium Deposits with Organic Gangue

Henry Basin, Utah

Cluff Lake, Saskatchewan

Lodeve, France

Springbok Flats, South Africa

Mulga Rocks, Western Australia

Letlhakane, Botswana

6


Letlhakane Uranium Project

A-Cap Resources

7 Cairns, D., et. al., Development of the Letlhakane Uranium Project, presented at Alta 2012 Conference by ACAP Resouces


Letlhakane Meandering Channel Facies

Cairns, D., et. al., Development of the Letlhakane Uranium Project, presented at Alta 2012 Conference by ACAP Resouces


9

• Detrital heavy mineral accumulations containing

orthobrannerite, uraninite, uraniferous zircon, monazite

• Uranium ionically bonded to long chain organic molecules in

carbonaceous mudstone (humate ore)

1. Primary Mineralisation

Reduced Oxidized

Humate U

Re-mobilised U Primary Mineralisation

Arkose

Letlhakane Mineralisation Styles




2. Oxide Mineralisation

•Variable weathering of primary mineralisation to depths of up

to 40 m.

•Distribution, grade & continuity of mineralisation mirrors

primary occurrences

•Uranium remains largely in-situ

•Dominant species include coffinite and uranophane occurring

as replacement of primary mineralogy

10

Oxide Mineralisation




3. Secondary Mineralisation

•Hosted by calcrete, calcareous mudstones and fractured,

non-calcarous oxidised mudstone

•Developed above the watertable (15 m) via remobilisation of

uranium from the oxide into the evaporative environment

•Dominance of hexavalent uranium minerals, e.g., carnotite,

francvillite

Backscatter Imag

11 Cairns, D., et. al., Development of the Letlhakane Uranium Project, presented at Alta 2012 Conference by ACAP Resouces


Letlhakane Ore Type Composition

12

Analysis Unit Kraken

Primary

Gorgon

Primary

Oxide Shallow

Mudstone

Calcrete

Al % 9.22 10.01 8.38 13.3 8.46

Fe % 0.68 1.15 2.72 0.99 1.17

Mg % 0.11 0.12 0.10 0.42 0.85

S % 0.13 0.68 0.2 0.05 0.26

Si % 25.8 23.3 - 25.4 20.9

U ppm 202 198 182 136 286

V ppm 329 522 234 138 214

Total C % 5.48 11.0 2.54 0.77 3.30

C Org % 4.34 9.59 2.43 0.38 0.82

CO3_C % 1.14 1.41 0.11 0.39 2.48


Letlhakane Preliminary Preg Robbing Evaluation

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-25.0

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

0 20 40 60 80 100

Ura

niu

m R

ec

ove

ry (

%)

Leach Time (Hours)

Aqueous Uranium Deportment – Weak Acid Leach

U Ext (Calcfrom LiquorAssay) %

Conditions

Temperature : Ambient

U Conc. in Initial Lixiviant : 269ppm U

SG : 19% Solids

Eh : ~500mV (Ag/AgCl)

Lixiviant Concentration : ~5g/L H2SO4

Acid Consumption : 13 -14 kg/t

P80 : 75μm



Testwork Equipment Column Testwork


Letlhakane Impact of Lixiviant Acid Concentration

15

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60 70 80 90 100

Ura

niu

m E

xtr

ac

tio

n (

%)

Leach Time (Day)

Kraken Primary – 2m Column Leach Test

T1: 48 g/L H2SO4

T2: 99 g/L H2SO4

T3: 145g/L H2SO4

Conditions

Agglomeration Acid : 10kg/t

P100 : 8mm


Letlhakane Impact of Varying Acid Concentration

16

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120

Ura

niu

m E

xtr

actio

n (

%)

Leach Time (Days)

Gorgon Primary Ore (Ore Sorter Accept Fraction) - 2m Column Leach Test

GA-6 : 25kg/t Agglomeration acid, 100g/L H2SO4 Lixiviant

GA-2 : 10kg/t Agglomeration acid, 50g/L H2SO4 Lixiviant

Conditions

P100 : 8mm

Irrigation Rate : 10L/m2/h


Letlhakane Impact of Solute Concentration

17

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

Ura

niu

m E

xtr

actio

n (

%)

Leach Time (Days)

Gorgon Primary Ore – 2m Column Leach Test

P24: Lixiviant makeup in water

P25: Lixiviant makeup in mature solution

Conditions

Agglomeration Acid :10kg/t

Lixiviant Concentration : 50g/L H2SO4

P100 : 19mm


Letlhakane Impact of Solute Concentration

18

0

5

10

15

20

25

30

35

0 20 40 60 80 100

Acid

Co

nsu

mp

tio

n (

kg

/t)

Leach Time (Days)

Gorgon Primary Ore – 2m Column Leach

P24: Lixiviant makeup in water

P25: Lixiviant makeup in mature solution

Conditions

Agglomeration Acid :10kg/t

Lixiviant Concentration : 50g/L H2SO4

P100 : 19mm


Letlhakane Ripios From Column Leach

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Letlhakane Proposed Flowsheet

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Rabbit Lake Flowsheet

21 Uranium Extraction Technology Technical Reports Series No. 359, 1993, p307

Comminution

Leaching

CCD

SX

Impurity

Precipitation

Uranium

Precipitation

Uranium

product

Residue

Neutralisation

Raffinate

Neutralisation

Tailings

Management

Facility

U/F

Raffinate

Loaded Strip

O/F


Letlhakane Proposed Flowsheet

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Process Equipment Heap Leach Stacking

Moore, P., Mining Magazine, April 2008


Process Equipment Heap Leach Pad


Process Equipment Heap Leach Ponds


MULGA ROCK

26

http://en.wikipedia.org/wiki/File:Acacia_aneura_habit.jpg


Mulga Rock Project Information

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250 km north east of Kalgoorlie-Boulder

(Regional city)

Covers a Uranium province including the

following deposits:

Emperor: 24.1 Mt at 500 ppm U3O8*

Shogun: 3.7 Mt at 590 ppm U3O8*

Princess: 1.9 Mt at 600 ppm U3O8*

Ambassador: 27.6 Mt at 470 ppm U3O8*

* U3O8 Resource estimate reported by EAMA in Company Update

Presentation. October 2014

http://www.eama.com.au/investors/presentations/


Mulga Rock Mineralisation

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Uranium is hosted within weathered Carbonaceous sandstone, Silt

and Sandy lignites

Fewster et al. 2010


Mulga Rock Mineralisation

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Uranium mineralisation:

Ionic free associated with carbonaceous material and lignite

Some coffinite and uraninite minerals have been reported

Pownceby et al. 2011

a) Uranium distribution map b) Uranium and carbon distribution map


Mulga Rock Appearance

Dark in Colour

Friable when handle

Pownceby et al. 2011

Fewster et al. 2010

Lignite Ore (Ambassador, 2009)

Mineralized Sand (Ambassador, 2009)

Lignite hosted uranium samples

Fewster et al. 2010


Mulga Rock Mineralogy

Shogun and Ambassador deposits (Douglas et al, 1993)

Mineral type Shogun Deposit Ambassador Deposit

Important minerals:

Organic U, Ti, V, Cr, REE U, Ti, V, Fe-Ti, REE

Sulfide / Sulfate Pyrite, galena, sphalerite,

covellite, chalcocite,

polydymite, anglesite,

gypsum, barite, U-S,

CoNiCoMoU-S, REE-Ca-S

Pyrite, galena, sphalerite,

FeNiCo-S, FeZnCd-S,

FeTi-S, ZnNiCoFe-S,

CeSmNd-S, CaCeSmNd-S,

UFeZnCoNi-S, U-S,

UFeZnNi-S, FeTiVSe-S,

CaCdCeFeNiZn-SO4

Other minerals types:

Silicates and oxides

Quartz type minerals Quartz type minerals

Heavy minerals Heavy minerals


Scoping Study testwork (Lawson et al. Ansto - 2011):

Organic carbon: 21%

S as sulfide: 3%

Loss of ignition: 39%

Mulga Rock Elemental Assay

Mineralized Lignite (Douglas et al. 1993)

Element Mean (ppm) Element Mean (ppm)

U 473 Y 102

Th 23 As 12

Co 219 Sc 54

Cu 483 W 12

Pb 88 Sb 1

Zn 1157 Au 0.022

Ce 325 Cr 131

La 123 Zr 525


Mulga Rock Scoping Leach Testwork

Conditions:

Pulverized Sample

Low slurry density (Dilute)

ORP: >500 mV (Ag/Ag/Cl)

Outcomes:

pH 1.5 and 40°C: 88% U

extraction

pH 1.0 and 60°C: 92% U

extraction

DIAGNOSTIC LEACH (Lawson et al. Ansto - 2011)


Mulga Rock Scoping Leach Testwork

“STANDARD” LEACH (Lawson et al. Ansto - 2011)

Conditions:

P80: 150µm

40% solids


pH 1.5 and 40°C

Outcomes:

64% U extraction

23 kg/t pyrolusite consumption


Mulga Rock Options

Lawson et al. Ansto - 2011

Processing Option Summary of Test

Conditions

Uranium

Extraction

(%)

Pyrolusite

Consumption

(kg/t)

“Standard Leach” P80: 150µm, 40% solids


pH 1.5 and 40°C, 24 h

64 23

“Standard Leach”

+ Resin

P80: 150µm, 40% solids


pH 1.5 and 40°C, 24 h

Resin in Leach

81 24

Roast + Carbonate leach Roasting: 6h in air at 650°C

Followed by:

Leach at 95°C 24 hours

30 g/L Na2CO3, 10g/L NaHCO3

Air sparging

33 Not applicable

Pyrolysis + Acid leach Pyrolysis: 6h under N2 at 550°C

Followed by: “Standard Leach”

9 70


Optimised conditions P80: 150µm, 40% solids

ORP: ~400 mV (Ag/Ag/Cl)

pH 1.0 and >40°C

Resin in Pulp

>90 Information Not

Available

Lawson et al. Ansto - 2011

Processing Option Summary of Test

Conditions

Uranium

Extraction

(%)

Pyrolusite

Consumption

(kg/t)


Lower pH



pH 1.0 and 40°C, 24 h

73 12


Lower ORP



pH 1.0 and 40°C, 24 h

70 0


Lower pH, Lower ORP

+ Resin



pH 1.0 and 40°C, 24 h

Resin in Leach

82 0

EAMA, 2013

Mulga Rock Options


Mulga Rock Process Flowsheet

Young, M. EAMA - 2014

Resin in pulp process due to carbonaceous nature of the ore

“Resin in pulp” preferred over “Resin in leach” allowing more aggressive

leaching conditions

ROMOre

PreparationMilling

Uranium Leach

Uranium RIP

Uranium

Precipitation

Drying /

Packaging

Cu/Zn/Ni/Co

Recovery

Tailings

Storage Facility


Parameters Letlhakane Mulga Rocks

Uranium

Mineralogy

•Primary mineralisation –

orthobrannerite, uraninite, uraniferous

zircon, monazite

•Oxide - coffinite and uranophane

•Secondary mineralisation – carnotite,

francvillite

•Coffinite and uraninite

minerals

Uranium

Association with

Organics

•Primary mineralisation uranium

ionically bonded to long chain organic

molecules in carbonaceous mudstone

(humate ore)

•Ionic Free associated with

carbonaceus material and

lignite

Uranium Ore

Grade (ppm)

•Approximately 200 ppm U •Approximately 470 ppm U

% Organic

Carbon

•0.5% to 10% •21%

Comparison Table Letlhakane Vs Mulga Rocks


Parameters Letlhakane Mulga Rocks

Comminution •P100 of 19mm •P80 of 150 micron

Leach Conditions • 2 Stage Heap Leach

• Strong acid (300g/L H2SO4) followed

by weaker acid leach (50-100g/L

H2SO4)

• 20-25˚C

•Tank leach and resin in pulp

•40% solids in slurry

•400mV (Ag/AgCl) ORP

•pH 1

•>40˚C

Comparison Table Letlhakane Vs Mulga Rocks


References

40

Young, M. Focus and Momentum. Presented at the Australian Uranium Conference 16-17 July 2014 by

Energy and Minerals Australia.

Young, M. Focus and Momentum. EAMA company presentation October 2014.

Energy and Minerals Australia. 2014 Annual Report. 2014



Lawson, J., Baker, M., Collier, D. and Ring, B. Extraction of Uranium from the Mulga Rock deposits in

Western Australia. Presented at the AusIMM International Uranium Conference 8-9 June 2011 by Ansto

Minerals.

Fewster, M. and Moreau, X. What’s new at Mulga Rock? Presented at the AusIMM International Uranium

Conference 16-17 June 2011 by Energy and Minerals Australia.

Pownceby M.I. and Johnson C. Geometallurgy of Australian uranium deposits. Ore Geology Reviews, 56, p

25-44. 2014

Pownceby, M.I., Aral, H., Hackl, R. Geometallurgy and processing of Australia’s uranium deposits.

Proceedings ALTA 2011 Uranium, Perth, WA, Australia, 26-27 May 2011. Alta Metallurgical Services. 2011

Fulwood, K.E. and Barwick, R.E. Mulga Rock uranium deposit, Officer basin. In: Geology of the Mineral

Deposits of Australia and Papua New Guinea, Ed. F.E. Hughes, pp 1621 – 1623. 1990

Douglas, G.B., Butt, C.R.M. and Gray, D.J., Mulga Rock uranium and multielement deposits, Officer basin,

WA. Regolith Expression of Australian Ore Systems. CRC LEME. 2003

Douglas, G.B., Butt, C.R.M. and Gray, D.J., Geochemistry, mineralogy and hydrogeochemistry of the

Ambassador multi-element lignite deposit in Western Australia. CSIRO. CRC LEME. 1993.


References

41

Cairns, D., et. al., Development of the Letlhakane Uranium Project, presented at Alta 2012 Conference by

ACAP Resources, 2012

Dunn, G.D and Teo, Y., The Critical Role of Gangue Element Chemistry in Heap and Agitated Tank Leaching

of Uranium Ores, presented at Alta 2012 Conference by Orway Mineral Consultants, 2012

Uranium Extraction Technology Technical Reports Series No. 359, International Atomic Energy Agency,

Vienna, 1993, p307

Leventhal, J.S., Roles of Organic Matter in Ore Deposits, U.S. Geological Survey, Denver, Colorado 80225

Rabbit Lake Tailings North Pit Expansion Project Process Description, Comeco, June 2011

Moore, P., Mining Magazine, April 2008

Dunn, G.M., Uranium Processing, IAEA Presentation, 2012


THANK YOU


Testwork Equipment Tank Leach Pilot Testwork

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Recovery of Uranium From Carbonaceous Ores€¦ · · 2014-11-07Recovery of Uranium From Carbonaceous Ores 1 By : Grenvil Dunn Nelson Mora ... Process Role(s) ... •Variable weathering