Zs. Berta-M. Csıvári

Technical Meeting on Uranium Exploration and Mining Methods

MECSEK-ÖKO Zrt., Pécs, Hungary

Amman, 17-20 November 2008

HISTORY OF THE URANIUM PRODUCTION IN MECSEK

Mecsek Mountain, Village:Kıvágószılıs

LOCATION OF THE SITELOCATION OF THE SITE

One district inshouthern

part of Hungary

Site is situated next tothe drinking waterchatchment area

Pécs

Tailing Pond

#1. Shaft

#2. Shaft

#3. Shaft

#4. Shaft#5. Shaft

0 1000 2000 3000 4000 5000( m )

TPP

T

Miningarea

Main task is: protectionof the drinking water basin

PRODUCTION SUMMARY (1958PRODUCTION SUMMARY (1958--97)97)

Type of ore Mass of ore Grade U Quantity of U Recovered and sold U

U in tailings (wastes)

million t g/t tonne tonne tonneOre exported 1.4 1 524 2 195

Waste rock* 19.3 53 1 029 1 029 Ore processed inthe mill 18.8 1 002 18 916 17 534 1 382

Heap leached ore 7.2 130 942 545 397

Total 46.8 23 082 18 103** 2 808

* including rejects from radiometric sorting** including 22 tonne uranium from water treatment Exploration1953-56

Opening of the mines1955-58

Mining 1958-97 Remedi1997-0883 M EUR

Processing, 1962-97Long-term mon. ~2.5 M EUR

EXPLORATION WORKEXPLORATION WORK

1952. Agreement was signed between the Hungarian and Soviet Governments on starting the geological survey on uranium deposits

1953. Soviet geologist equipped with appropriate instruments arrived in Hungary one of that teams (geophysics T. Csuprova and L. Puharszkij) detected unusual high anomaly at MECSEK (Kövágoszılıs). This event is considered as the discovery the uranium deposit in Hungary

Geiger-Müller counterMeasuring the emanation activityDetermination of U.

Geiger-Müller counter

Foot-gamma and car-borne prospecting,

Digging trenches, shallow exploration shafts, hand-drillingAirborne gamma- prospecting

Emanation measurements on the sitesWater analysis for UComplex geological mineralogical and geochemical evaluation of the data

Deep drillingsGeophysical measurements using (electrical conductivity survey) for detecting e.g. the foults

METHODS OF PROSPECTINGMETHODS OF PROSPECTING

Lenght of the drillings

Quantity of the drillings

LENGHT AND NUMBER OF THE DRILLINGSLENGHT AND NUMBER OF THE DRILLINGS

m N

GEOLOGICAL GEOLOGICAL MAP and MAP and CROSSCROSS--SECTION SECTION OF THE OF THE

WW--MECSEKMECSEK

S

N

S N

Uranium was found in the upperPermian geological set in grayish/greensandstone

The ore is situated in the upper Permian sandstonein greyish-green layers (productive zone)Total estimated solid ore reserves (U~0.12%):

39 Mt (up to –1300 m depth)Mined out solid ore :

20 Mt (28 Mt in form of run-off-mine ore )Reserves left behind: 19Mt

12 Mt (1200-1300 m) 7 Mt (1000-1200 m)

GEOLOGICAL RESERVESGEOLOGICAL RESERVES

URANIUM MINERALISATION IN THE OREURANIUM MINERALISATION IN THE ORE

Uranium oxides in clayey-kvarc

cementing phase BranneriteSecondary minerals (in

ultraviolet light)Main uranium minerals:•Uranium oxides•Coffinite•Brannerite•Secondary minerals

Uranium oxide (1) and coffinite (2) in

carbonateous cementing phase

572000 573000 574000 575000 576000 577000 578000 579000 580000 581000 582000 58300079000

80000

81000

82000

83000

84000

85000

86000

87000

88000

89000

90000

II.

V.

I.

III.

IV.

KÕVÁGÓSZÕLÕS

CSERKÚT

KÕVÁGÓTÖTTÖS

BAKONYA

PÉCSRoad #6

0m 2000m 4000m 6000m 8000m 10000m

MINING PLOT AREAMINING PLOT AREA

UNDERGROUND MINES UNDERGROUND MINES MINE HEADFRAMESMINE HEADFRAMES

7.3 Mt

Only underground mining ( 5 mines, 119-1118 m); Two shallow (119-149m) and two deep shafts(700-1118 m), one with adits;

46.4 m gallery /1000t ore; The ore was found in form of lenses, therefore the run-off-mine ore was diluted with waste rocks; There was no backfilling of workings.

Shaft N4 1971 (-700 m) Shaft N5 1978 (-1118 m)

1.35Mt3.1 Mt

Shaft N1 1957 (-119 m)

SOME PHOTOS ON THE UNEDERGROUND MINING WORKSSOME PHOTOS ON THE UNEDERGROUND MINING WORKS

EXPLORATIOM IN MINE EXPLORATIOM IN MINE (DRILLINGS FROM GELLERIES)(DRILLINGS FROM GELLERIES)

242 m mine exploration drilling /1000t ore;

GEOPHYSICAL EXPLORATIONS GEOPHYSICAL EXPLORATIONS IN THE MINEIN THE MINE

Logging

Documentatioon of the gallery walls

IMPROVEMENT OF THE WORK CONDITIONS IMPROVEMENT OF THE WORK CONDITIONS FOR MINERS OVER 1956FOR MINERS OVER 1956--97 PERIOD97 PERIOD

1 WLM=5 mSv

WLM/a

Radiometric sorting station (with crushing

and sizing)Capacity: ~1.2 Mt/a

Capacity of the mill(for ore): 600 kt/a

35 ha

PROCESSING PLANTPROCESSING PLANT

Run-off-mine ore

Waste rockU<100 g/t

Low-grade ore U=100-230 g/t

Industrial-grade oreU>230 g/t

Radiometric up-grading

Mill-grade oreU~1000g/tγ=67%

RejectU<170 g/tγ=33%

Heap LeachingU~140 g/t (CO2~3% S~0.1%)

U=100-170g/tU<100 g/t

For HL alkaline leaching was selected because of high CO2 and low S content

RCS

To the mill

GGENERALENERAL FLOWFLOW SHEETSHEET OF THEOF THEOREORE PROCESSINGPROCESSING. R. RADIOMETRICADIOMETRIC SORTINGSORTING

OPERATION OF THE RADIOMETRIC SORTING STATION OPERATION OF THE RADIOMETRIC SORTING STATION AND THE EFFICIENCY OF THE R&D WORKSAND THE EFFICIENCY OF THE R&D WORKS

ND 424L 76X50

Detectionefficiency: 5600 cps/gU

Decreasing thebackground and installation more sensitivedetectors

The U in rejectsdecreased, the% of itsincreased

Closingperiod

1958

Performance of the sorting

Leaching (in four stages)

U rec.~95%200 g/l 15 g/l

Recovery of U from pulp

Product:Ca-diuranate

Neutralization of the barren pulp

(pH~7-7.5)

Disposal in tailings ponds(TDS~22 g/l, MgSO4 + NaCl)

CaO~25 kg/t; CaCO3~11.6 kg/t

Mineralization: brannerite;

H2SO4~100 kg/t

Ion exch.: 0.1 l/tHCl~5.3 kg/tNaCl~4.4 kg/t

Mill-grade ore (18.9Mt)(U~0.1%) CO2~ 4-2.6%

Crushing and Milling

CaO

Pyrolusite

Refractory oreCo-current syst.

GGENERALENERAL FLOW SHEETFLOW SHEET OF THE MILLOF THE MILL PROCESSPROCESSAcid leaching

QUANTITY AND THE GRADE QUANTITY AND THE GRADE OF THE ORE PROCESSED (1962OF THE ORE PROCESSED (1962--97)97)

DIRECT COST DISTRIBUTION DIRECT COST DISTRIBUTION BETWEEN THE MAIN MATERIALSBETWEEN THE MAIN MATERIALS

Material Spec. cons.kg/tSulphuric acid 102.5Lime 21.6Hydrochloric acid 1.8Pyroluzite 22Salt (NaCl) 4.2Anion exchanger 0.04Ball 0.99Limestone 18.6Electric energy 31.75 kWh/t

Cost distribution. %

Pad construction for heaps

The pad was sealed with plasticfoil strips(and sticked with bitumen)

At the very beginning 1.2 m wide foil strips later on wider ones were used

Drain from WRWood chips

PAD PREPARATION FOR HEAPS PAD PREPARATION FOR HEAPS (1965)(1965)

View on the heaps

33 ha

~5 Mt

Site N2

ColumnsPad readyfor lining

HEAP HEAP LLECHING SITEECHING SITESS

Recovery :55-70%5 kgNa2CO3/t

Employees And Uranium Output Between 1956-1997.

010002000300040005000600070008000900019

56.

1958

.19

60.

1962

.19

64.

1966

.19

68.

1970

.19

72.

1974

.19

76.

1978

.19

80.

1982

.19

84.

1986

.19

88.

1990

.19

92.

1994

.19

97.

Year

Emplo

yees

0

100

200

300

400

500

600

700

800

Metal

l in To

nne

EmployeesUranium in tons

130 Employees

Employees of the companyCHANGE THE NUMBER OF EMPLOYEESCHANGE THE NUMBER OF EMPLOYEESAND THE U PRODUCTION BY YEARSAND THE U PRODUCTION BY YEARS

2008

Prod. cost >60 $/kg

REMEDIATION OF THE SITE REMEDIATION OF THE SITE (1998(1998--2008) 2008)

Government Decree 2161/1994. (30. XII.) on the future of the uranium mining, decision on shut down the uraniummining Elaboration of the remediation concept for the site (1996)Environmental Impact Study Report and issuing the Environmental Licence by the authorities the MPL for the critical components (1997)Submission to the Government the Investment Plan which was divided into 10 sub-remediation project (1997)

A Beruházási Program létesítményi sorainak költségeloszlás diagramja 13%

8%

4%

11%

40%

6%

1%

1%

3%9%

5%

Földalatti létesítmények felhagyása Külszíni létesítmények és területek rek.Meddıhányók és környezetük rek. Perkolációs dombok és környezetük rek.Zagytározók és környezetük rek. Bányavíz kezelésVillamos energia hálózat rekonstrukciója Víz- és csatornahálózat rekonstrukciójaEgyéb infrastrukturális szolgáltatás Egyéb tevékenységTartalék az 1998-2003. éves összegre

Planned cost of remediation (1997): 18.5 Billion HUF (~80 million US$)~ 4 US$/kgU; Actual cost (2008)~100 US$/kgU

Closing of underground minesReclamation of waste rock pilesReclamation of tailings pondsReconstruction of the electricnetworkOther infrastructural serviceReserve

Reclam. of surficial facilities and areasReclamation of heap leaching sitesWater treatmentReconstr. of water and sewage systemOther activities (staff etc.)

DIRECT COST DISTRIBUTION DIRECT COST DISTRIBUTION BETWEEN THE MAIN MATERIALSBETWEEN THE MAIN MATERIALS

Requirements Requirements establishedestablished byby thethe authoritiesauthorities. . MPL of MPL of thethe radiologicalradiological contaminantscontaminants

Restoration of waste rock piles and tailings ponds

• 222Rn exhalation rate: 0.74 Bq/(m2s)• 222Rn concentration outdoors: background + 20 Bq/m3• Ambient gamma dose rate: background + 200 nGy/h• 226Ra activity concentration of soil

- in the uppermost 15 cm layer: background + 180 Bq/kg- in the following 15 cm layers: background + 550 Bq/kg

MPL- Maximum permitted level

All fuel-contaminated soil was removed (4347 m3) (3255 m3 rocks, treated microbiologically on surface);

Backfilling of shafts mainly with waste rocks found on the site;Shaft towers have been blasted, together with most facility buildings;

All sites are remediated (most part of the waste rocks was hauled to WPN3);

Total cost of remediation: ~11. 7 million:US $~0.25 US $/t of mined out rocks (46.8 Mt)

RREMEDIATIONEMEDIATION OF THE SHAFTS OF THE SHAFTS AND AND

THEIRTHEIR SURROUNDINGSSURROUNDINGS

Schaft No. IV. and ventillation shaft No. IV. before and after the remediation

→

→

Remediation of the ventilation shaft N4 Remediation of the ventilation shaft N4 and transporting shaft N4and transporting shaft N4

0 4,000,000 8,000,000 12,000,000

1999-08-28

2003-08-27

2007-08-26

2011-08-25

2015-08-24

2019-08-23

2023-08-22

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000volume of cavities [m3]

-800

-600

-400

-200

0

200

400

water

leve

l [mAs

l]

Adit level

Legendwater level (mAsl)volume of cavities (m3)

2016-2018

±0

-700

Sandstone/ClaystoneP-T SandstoneSandstone

Tectonic zoneUranium ore

Legend

Anhydirtemarl/

Siltstoneaquitard

Limestone M Sand and clay

Pl Loose sand (aquifer)2

Northern shaftsSouthern shaftAdit

D

D- drinking water aquifer

ChallangeChallange: : weatherweather mineminewaterwater fromfrom deepdeep minesmineshas has toto be be treatedtreated??

FLOODING OF THE MINESFLOODING OF THE MINES

I II IV VMine water treatment

IIIWaste rockpiles

IIII II

Mines

To dischargebasin

U~0.4 mg/l

U<1 mg/lU~4 mg/l

FA

On sitetreat.

UO4x2H2O

Under flooding

MINE WATER TREATMENTMINE WATER TREATMENT

Total mass of waste rocks (on 10 piles): 19.2 MtU~1055 t

WP N3: 12.2 Mt

For backfilling only 0.1 Mtof waste rocks were used

Measures:Relocation, hauling, reconturingCovering with ~1 m thick soil layer

RevegetationSeepage treatment (U removing)

Total cost of remediation: ~2.39 million US $ (incl. 2 million US $ for HL wastes);

~0.09 US $/t ( waste rocks + HL residues)

RREMEDIATIONEMEDIATION OF THE WASTE ROCK PILESOF THE WASTE ROCK PILES

The most contaminatedsoil was found on the ore and acidstorage areas, as well asunder the yellow cake production facilities.

Scraps of mill balls

Total cost of remediation of the mill site:~ 5 million US $

Demolition

Clean-up with replacingof the contaminated soil(0.35 Million m3)

RREMEDIATIONEMEDIATION OF THE MILL SITEOF THE MILL SITE

Multi-layer covering cap (1,5-1,6 m)Surface stabilisation by

horizontal and verticaldrain and geogrid (12,6 ha)

Μεντεστ⌡ κυτσ⌠ρ δρνφαλ ρενδσζερ α φελσζν αλαττι ϖζταρτ⌠κβα κιϕυτ⌠ττ σζεννψεζ⌡δσ ελτ⟨ϖολτ⟨σα χλϕ⟨β⌠λContaminated groundwater pumping out by deep and shallow groundwaterwells and continuous draniage trenches

max. 740 mBq/m2s

4000 mBq/m2s

600-800 mm/a

30-60 mm/a

Radon barrier

min. 200 yearsInfiltration barrierTP I.

- 1962-1980,1990-1997

- 100 ha- 15 768 kt tailings- 71,3 g/t U- 1 125 t UTP II.- 1981-1989- 59.3 ha- 4 599 kt tailings- 55.8 g/t U- 257 t U

RREMEDIATIONEMEDIATION OF THE TAILINGS PONDSOF THE TAILINGS PONDS

~20 Mt

After covering tailings pond I., natural background values are accepted

Long Long termterm changechange of of effectiveeffective dosedosecomponentscomponents inin PellPelléérd, 2000 rd, 2000 –– 2008.2008.

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

márc.00aug.00

jan.01

jún.01

nov.01

ápr.02

szept.02jan.03

jún.03

nov.03

ápr.04

szept.04febr.05

júl.05

dec.05máj.06

okt.06

márc.07aug.07

jan.08

Idı

Effec

tive d

ose,

mSv/y

Külsı gamma Rn-termék Aeroszol alfa Összes dózis

Terrestiral background Hun. average = 0,8 mSv/y

Population dose limit: nat. background +1 mSv/y

TREND!?Trend?

2000 2008

Ambient gamma Aerosol alpha Summa doseRn progeny

Decreasing of the effective doseduring the covering of the TPs

TTHEHE REMEDIATED TAILINGS PONDREMEDIATED TAILINGS POND

577000 577500 578000 578500 579000 579500 580000 58050075000

75500

76000

76500

77000

77500

78000

78500

79000

A-01

B-01

C-01

H/1

U-09/1

U-10/1

U-11/1U-13/1

U-14/1

U-16/1

U-17/1

U-18/1

U-19/1

U-20/1

U-21/1

V-01/1

V-02/1

V-03/1

V-05/1

V-07/1

V-08/1

V-10/1

V-11/1

V-13/1

V-14/1

V-15/1

V-16/1

V-17/1

V-18/1

V-19/1

V-20/1

V-21/1

V-22/1V-23/1

V-24/1

V-25/1

V-26/1

V-27/1

V-28/1

V-29/1

V-30/1

V-32/1

V-33/1

V-35/1

V-36/1

V-37/1

V-38/1

V-39/1

V-41/1

VIII/1

X/1

XIII/1

XVIII/1

XXVII/1

Bicsérd-2/F-5

Pellérd-1/F-5

ZA-1

ZB-1

ZC-1

ZE-1

ZG-1 ZH-1

ZI-1

ZB

ZC

ZD

ZF

ZIZJ R-11

R-12

R-15

R-16

TDS (mg/l) in the shallow groundwater around the tailing ponds in 2003

1000 4000 8000 12000 16000 20000

0 500 1000 1500 2000

577000 577500 578000 578500 579000 579500 580000 58050075000

75500

76000

76500

77000

77500

78000

78500

79000

A-02

B-02

C-02

G

H

U-09

U-10

U-11 U-12 U-13

U-15

U-16

U-17

U-18

U-21

U-22

U-23

V-01

V-03

V-05

V-07

V-09

V-12

V-13

V-14

V-15

V-17

V-21

V-22V-23

V-24

V-25

V-26

V-27V-29

V-34

V-36

V-37

V-38

V-40

VII

XIIIBicsérd-2/F-3

Pellérd-1/F-3

ZA-2

ZB-2

ZC-2

ZD-2

ZE-2

ZF-2

ZG-2

TDS (mg/l) in the deeper groundwater around the tailing ponds in 2003

1000 4000 8000 12000 16000 20000

0 500 1000 1500 2000

5-20 m25-40 m

TPI

TPII

18 g/l 4 g/l

Shallow GW5-20 m

Deeper GW25-40 m

TDS

U~50 µg/l

GGROUNDWATERROUNDWATER CONTAMINATIONCONTAMINATION

Pellérd

Péc s e

r - Ba ch

Wasserbehandlungsbetrieb

I. Schlammteich

II. Schlammteich

SammlerschachtDekontaminierungs BrunneMonitoring BrunneDrainleitungRohrleitungsnetzWasserbehandlungsbetriebTrinkwasser Brunne

GW extraction wells: 15+12 piecesDeep dranage: 2.8 kmVolume of extracted water: ~ 0.43 Mm3+0.3 Mm3

Water treatment: pump and treat with lime milk.Sludge is deposited on WP3 (dry 3-4 kt/y).

Yearly operation cost: 800 000 US $ (~1.9 US $/m3)

TP2

TP1

GGROUNDWATERROUNDWATER RESTORATION SYSTEMRESTORATION SYSTEM

CONTROLLING OF THE COLLECTED DISCHARGECONTROLLING OF THE COLLECTED DISCHARGE

λmax.<2000 µS/cм

Limits: U<2 mg/lTDS<5 g/lRa<1.1 Bq/lV, m3/h ?

Vmax.=f(v, λmax, λ1,λ2)

v, λ1

λ2

Treated mine waterTreated and untreatedgroundwater

Receiverλ~1450 µS/cm

λ~1800 µS/cm

Discharge basin

pH

Volume of the discharged water through the Volume of the discharged water through the integrated system (2007) integrated system (2007)

Non-treated water(e.g. deeper GW,Northern mines)

0.52 Mm3

Treated groundwater0.30 Mm3

Treated mine water0.32 Mm3

Discharge point LimitsTDS: 5 g/lU: 2 mg/l

In the receiver:Sp. el. cond: 2 mS/cm

Ra: 1.1 Bq/l

TDS: 3.44 g/lU: 0.12 mg/lRa: 0.19 Bq/l

Receiver (Pécsi-víz)1.14 Mm3

Thank you for your attention!Thank you for your attention!